be retrieved from reflection data and a background model. Initially, the focusing function was defined such that it focuses inside the medium of interest as a point in time and in space (e.g. Wapenaar et al., 2014). The focusing property is used to retrieve the up- and downgoing Green’s functions associated to a virtual point source or receiver inside the medium. Subsequently, the retrieved Green’s functions are used to compute an image. Meles et al. (2017) introduced a new focusing function that focuses as a plane wave inside the medium. The new focusing function allows to retrieve medium responses associated to

virtual plane wave sources or receivers inside the medium. Hence, imaging based on areal-sources as suggested by Rietveld et al. (1992) becomes possible including the benefits of the Marchenko method. In the following we compare Marchenko imaging using point and plane wave focusing.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-15","","","","","","" "uuid:ec82b4a8-3f09-45c2-9506-1453e3a8d6fe","http://resolver.tudelft.nl/uuid:ec82b4a8-3f09-45c2-9506-1453e3a8d6fe","Fast nonrecursive 1D inversion by filtering acoustic-reflection data","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Treitel, Sven (Tridekon)","","2018","We derive a fast acoustic inversion method for a piecewise homogeneous horizontally layered medium. The method obtains medium parameters from the reflection response. The method can be implemented to obtain the parameters on either side of a reflector at an arbitrary depth. Three processing steps lead to the inversion result. First, we solve a modified Marchenko type equation to obtain a focusing wavefield. We then apply wavefield continuation across a reflecting boundary to the focusing wavefield and retrieve the reflection coefficient of a reflector as a function of horizontal slowness. Finally, we use the reflection coefficient to obtain the velocities and the ratio of the densities above and below the reflector. Because the two-way traveltime difference of the primary reflection and the one above it becomes known during the process, the thickness of the layer above the reflector is also found. The method can be applied multiple times in different zones, or recursively in a target zone without having to solve more Marchenko type equations. The numerical example illustrates that the method works well on modeled data without the need for a priori model information.","inversion; processing; acoustic","en","conference paper","SEG","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-04-19","","","","","","" "uuid:8511a3bc-e21c-4993-8438-af7e39c77388","http://resolver.tudelft.nl/uuid:8511a3bc-e21c-4993-8438-af7e39c77388","Marchenko redatuming for multiple prediction and removal in situations with a complex overburden","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2018","Internal multiples can create severe artefacts in seismic imaging, especially when our zone of interest is overlain by a complex overburden. These artefacts can mask structures, which has a strong effect on the interpretation of the image. Therefore, multiple prediction and removal is of significant importance for correct imaging and interpretation in settings with a complex overburden.

We propose an adaptive double-focusing method to predict and subtract the internal multiples that were generated in the overburden. This method is a form of the Marchenko method, that can retrieve the directionally-decomposed Green's functions between virtual sources and virtual receivers anywhere inside the subsurface. The retrieved Green's functions contain all orders of multiple scattering. The method only requires the single-sided reflection response and a smooth velocity model as input. Instead of conventional imaging methods, that assume that the wavefield only consists of single-scattered waves (and thus create imaging artefacts when multiple scattering is present), we now use the multiple-scattered Marchenko wavefields for correct redatuming and imaging.

We apply our method to 2D and 3D field data that were recorded in settings where imaging and interpretation is hindered by a complex overburden. First, we create virtual sources and virtual receivers directly above our zone of interest. Next, we use the retrieved Marchenko wavefields to predict and subtract the internal multiples that were generated in the overburden. Masked structures become visible after multiple removal, which significantly improves the geological interpretability. Therefore, we conclude that the adaptive double-focusing method (Marchenko redatuming) is capable of correctly predicting and removing internal multiples generated in the overburden.","","en","conference paper","","","","","","Abstract S24A-03 presented at 2018 Fall Meeting, AGU, Washington, D.C., 10-14 Dec. Session: [S24A] Frontiers in Theoretical and Computational Seismology I","","2019-06-11","","","","","","" "uuid:201a0468-4228-4f75-a579-a29f62b825f2","http://resolver.tudelft.nl/uuid:201a0468-4228-4f75-a579-a29f62b825f2","Q‐factor Estimation and Redatuming in a Lossy Medium Using the Marchenko Equation","Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2018","Marchenko Imaging is a new technology in geophysics, which enables us to retrieve Green's functions at any point in the subsurface having only reflection data. One of the assumptions of the Marchenko method is that the medium is lossless. One way to circumvent this assumption is to find a compensation parameter for the lossy reflection series so that the lossless Marchenko scheme can be applied. The main goals of this work are to: [1] use the Marchenko equation to estimate the attenuation in the subsurface, [2] find a compensation

parameter for the lossy reflection series so that the lossless Marchenko scheme can be applied. We propose a novel approach which makes it possible to calculate an effective temporal Q‐factor of the medium between a virtual source in the subsurface and receivers at the surface. This method is based on the minimization of the artefacts produced by the lossless Marchenko scheme. Artefacts have a very specific behavior: if the input data to the Marchenko equation are over‐ or under‐ compensated, the resulting artefacts will have an opposite polarity. Thus, they can be recognized. This approach is supported by a synthetic example for a 1D acoustic medium without a free surface.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-14","","","","","","" "uuid:013a0e81-3a84-4013-975c-4a2624fb4b0e","http://resolver.tudelft.nl/uuid:013a0e81-3a84-4013-975c-4a2624fb4b0e","Virtual seismology: from hydrocarbon reservoir imaging to induced earthquake monitoring","Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); Staring, M. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2018","Recent developments in exploration seismology have enabled the creation of virtual sources and/or virtual receivers in the subsurface from reflection measurements at the earth's surface. Unlike in seismic interferometry, no physical instrument (receiver or source) is needed at the position of the virtual source or receiver. Moreover, no detailed knowledge of the subsurface parameters and structures is required: a smooth velocity model suffices. Yet, the responses to the virtual sources, observed by the virtual receivers, fully account for multiple scattering. This new methodology, which we call virtual seismology, has led to a breakthrough in hydrocarbon reservoir imaging, as is demonstrated in a companion paper (Staring et al., Marchenko redatuming for multiple prediction and removal in situations with a complex overburden). The aim of the present paper is to discuss applications of virtual seismology beyond exploration seismology, in particular induced earthquake monitoring, and to highlight the connections between these applications. The ability to retrieve the entire wave field between (virtual or real) sources and receivers anywhere in the subsurface, without needing a detailed subsurface model, has large potential for monitoring induced seismicity, characterizing the source properties (such as the moment tensor of extended sources along a fault plane), and forecasting the response to potential future induced earthquakes. This will be demonstrated with numerical models and preliminary real-data results.","","en","conference paper","","","","","","Abstract S53A-03 presented at 2018 Fall Meeting, AGU, Washington, D.C., 10-14 Dec. Session: S53A On the Symbiosis Between Fundamental and Exploration Geophysics I","","2019-06-14","","","","","","" "uuid:69b76fb7-85ff-46df-9865-2375ebda01de","http://resolver.tudelft.nl/uuid:69b76fb7-85ff-46df-9865-2375ebda01de","Artefact-Free Imaging by a Revised Marchenko Scheme","Zhang, L. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging)","","2018","A revised Marchenko scheme that avoids the need to compute the Green’s function is presented for artefact-free image of the subsurface with single-sided reflection response as input. The initial downgoing Green’s function which can be modelled from a macro model is needed for solving the revised Marchenko equations instead of its inverse. The retrieved upgoing focusing function can be correlated with the modelled initial downgoing Green’s function to image the medium without artefacts. The numerical example shows the effectiveness of the revised scheme in a 2D layered case.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-14","","","","","","" "uuid:459fdf96-c15d-45a3-aa93-89c03b17e985","http://resolver.tudelft.nl/uuid:459fdf96-c15d-45a3-aa93-89c03b17e985","Implementation of the marchenko method","Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","The Marchenko method makes it possible to compute subsurface-to-surface Green's functions from reflection measurements at the surface. Applications of the Marchenko method have already been discussed in many papers, but its implementation aspects have not yet been discussed in detail. Solving the Marchenko equation is an inverse problem. The Marchenko method computes a solution of the Marchenko equation by an (adaptive) iterative scheme or by a direct inversion. We have evaluated the iterative implementation based on a Neumann series, which is considered to be the conventional scheme. At each iteration of this scheme, a convolution in time and an integration in space are performed between a so-called focusing (update) function and the reflection response. In addition, by applying a time window, one obtains an update, which becomes the input for the next iteration. In each iteration, upgoing and downgoing focusing functions are updated with these terms. After convergence of the scheme, the resulting upgoing and downgoing focusing functions are used to compute the upgoing and downgoing Green's functions with a virtual-source position in the subsurface and receivers at the surface. We have evaluated this algorithm in detail and developed an implementation that reproduces our examples. The software fits into the Seismic Unix software suite of the Colorado School of Mines.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:048b6e7c-398b-42ee-8d9b-53c693cc3023","http://resolver.tudelft.nl/uuid:048b6e7c-398b-42ee-8d9b-53c693cc3023","A new approach to separate seismic time-lapse time shifts in the reservoir and overburden","Liu, Y. (Norwegian University of Science and Technology); Landrø, Martin (Norwegian University of Science and Technology); Arntsen, Børge (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","For a robust way of estimating time shifts near horizontal boreholes, we have developed a method for separating the reflection responses above and below a horizontal borehole. Together with the surface reflection data, the method uses the direct arrivals from borehole data in the Marchenko method. The first step is to retrieve the focusing functions and the updown wavefields at the borehole level using an iterative Marchenko scheme. The second step is to solve two linear equations using a least-squares minimizing method for the two desired reflection responses. Then, the time shifts that are directly linked to the changes on either side of the borehole are calculated using a standard crosscorrelation technique. The method is applied with good results to synthetic 2D pressure data from the North Sea. One example uses purely artificial velocity changes (negative above the borehole and positive below), and the other example uses more realistic changes based on well logs. In the 2D case with an adequate survey coverage at the surface, the method is completely data driven. In the 3D case inwhich there is a limited number of horizontal wells, a kinematic correct velocity model is needed, but only for the volume between the surface and the borehole. Possible error factors related to the Marchenko scheme, such as an inaccurate source wavelet, imperfect surface multiples removal, and medium with loss are not included in this study.","","en","journal article","","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","","" "uuid:ee0b3190-beb4-4de6-bdc8-2a25c569dbbb","http://resolver.tudelft.nl/uuid:ee0b3190-beb4-4de6-bdc8-2a25c569dbbb","A lossless earth Green's function representation between any two subsurface points from surface reflection GPR data","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","We present a three-dimensional scheme that can be used to compute the electromagnetic impulse response between any two subsurface points from surface reflection data measured at a single surface of a lossless medium. The scheme first computes a virtual vertical radar profile using the Marchenko scheme from which focusing wavefields are computed. With the aid of the Green's functions of the virtual vertical radar profiles these focusing wavefields are then used to compute the Green's function between any two points in the subsurface. One point is a virtual receiver and the other point is a virtual source. Virtual radar images can be created as well as the whole time evolution of the radar wave field throughout the subsurface generated by any subsurface virtual source. We show with a numerical example that the method works well in a one-dimensional configuration.","3D GPR; autofocusing; interferometry; virtual receiver; virtual source","en","conference paper","Institute of Electrical and Electronics Engineers Inc.","9781509054848","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:0ec47f8d-06ec-4d2a-8cb6-2532fb2cd38c","http://resolver.tudelft.nl/uuid:0ec47f8d-06ec-4d2a-8cb6-2532fb2cd38c","A Marchenko equation for acoustic inverse source problems","van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Johnson, Jami L. (University of Auckland); van Wijk, K. (University of Auckland); Singh, S. (University of Edinburgh); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","From acoustics to medical imaging and seismology, one strives to make inferences about the structure of complex media from acoustic wave observations. This study proposes a solution that is derived from the multidimensional Marchenko equation, to learn about the acoustic source distribution inside a volume, given a set of observations outside the volume. Traditionally, this problem has been solved by backpropagation of the recorded signals. However, to achieve accurate results through backpropagation, a detailed model of the medium should be known and observations should be collected along a boundary that completely encloses the volume of excitation. In practice, these requirements are often not fulfilled and artifacts can emerge, especially in the presence of strong contrasts in the medium. On the contrary, the proposed methodology can be applied with a single observation boundary only, without the need of a detailed model. In order to achieve this, additional multi-offset ultrasound reflection data must be acquired at the observation boundary. The methodology is illustrated with one-dimensional synthetics of a photoacoustic imaging experiment. A distribution of simultaneously acting sources is recovered in the presence of sharp density perturbations both below and above the embedded sources, which result in significant scattering that complicates the use of conventional methods.","","en","journal article","","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:644e9cc5-1e9a-43ec-b7cf-7f96fc3557bf","http://resolver.tudelft.nl/uuid:644e9cc5-1e9a-43ec-b7cf-7f96fc3557bf","A single-sided representation for the homogeneous Green's function of a unified scalar wave equation","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","","","en","journal article","","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:fd8655a1-35e5-4fa0-803b-361e98b8d5af","http://resolver.tudelft.nl/uuid:fd8655a1-35e5-4fa0-803b-361e98b8d5af","Cross-correlation beamforming","Ruigrok, E.N. (Utrecht University; Royal Netherlands Meteorological Institute); Gibbons, Steven; Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","An areal distribution of sensors can be used for estimating the direction of incoming waves through beamforming. Beamforming may be implemented as a phase-shifting and stacking of data recorded on the different sensors (i.e., conventional beamforming). Alternatively, beamforming can be applied to cross-correlations between the waveforms on the different sensors. We derive a kernel for beamforming cross-correlated data and call it cross-correlation beamforming (CCBF). We point out that CCBF has slightly better resolution and aliasing characteristics than conventional beamforming. When auto-correlations are added to CCBF, the array response functions are the same as for conventional beamforming. We show numerically that CCBF is more resilient to non-coherent noise. Furthermore, we illustrate that with CCBF individual receiver-pairs can be removed to improve mapping to the slowness domain. An additional flexibility of CCBF is that cross-correlations can be time-windowed prior to beamforming, e.g., to remove the directionality of a scattered wavefield. The observations on synthetic data are confirmed with field data from the SPITS array (Svalbard). Both when beamforming an earthquake arrival and when beamforming ambient noise, CCBF focuses more of the energy to a central beam. Overall, the main advantage of CCBF is noise suppression and its flexibility to remove station pairs that deteriorate the signal-related beampower.","Beamforming; Cross-correlation; Waveform characterization","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:19810c33-dcb1-48de-9eec-87376d1fa01c","http://resolver.tudelft.nl/uuid:19810c33-dcb1-48de-9eec-87376d1fa01c","Full-field multidimensional deconvolution to retrieve body-wave reflections from sparse passive sources","Hartstra, I.E. (TU Delft Applied Geophysics and Petrophysics); Almagro Vidal, C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","Our objective is to complement lithospheric seismic tomography with an interferometric method to retrieve high-resolution reflectivity images from local earthquake recordings. The disadvantage of using local earthquakes for the retrieval of reflected body-waves is their usual sparse distribution. We propose an alternative formulation of passive seismic interferometry by multidimensional deconvolution (MDD) which uses the multiples in the full recordings to compensate for missing illumination angles. This method only requires particle-velocity recordings at the surface from passive transient sources and retrieves body-wave reflection responses without free-surface multiples. We conduct an acoustic modelling experiment to compare this formulation to a previous MDD method and Green’s function retrieval by crosscorrelation for different source distributions. We find that in the case of noise-contaminated recordings obtained under severely limited and irregular illumination conditions, the alternative MDD method introduced here still retrieves the complete reflection response without free-surface multiples where the other interferometric methods break down.","Interferometry; Body waves; Coda waves","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:5bf1b74f-1582-40e0-bdc3-9ec696cdb67d","http://resolver.tudelft.nl/uuid:5bf1b74f-1582-40e0-bdc3-9ec696cdb67d","Deep ocean sound speed characteristics passively derived from the ambient acoustic noise field","Evers, L.G. (TU Delft Applied Geophysics and Petrophysics; Royal Netherlands Meteorological Institute); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); Heaney, KD (Ocean Acoustical Services and Instrumentation Systems); Snellen, M. (TU Delft Aircraft Noise and Climate Effects)","","2017","The propagation of acoustic waves in the ocean strongly depends on the temperature. Lowfrequency acoustic waves can penetrate the ocean down to depths where few in situ measurements are available. It is therefore attractive to obtain a measure of the deep ocean temperature from acoustic waves. The latter is especially true if the ambient acoustic noise field can be used instead of deterministic transient signals. In this study the acoustic velocity, and hence the temperature, is derived in an interferometric approach from hydrophone array recordings. The arrays were separated by over 125 km, near Ascension Island in the Atlantic Ocean, at a depth of 850 m. Furthermore, the dispersive characteristics of the deep ocean sound channel are resolved based on the retrieved lag times for different modes. In addition, it is shown how the resolution of the interferometric approach can be increased by cross correlating array beams rather than recordings from single-sensor pairs. The observed acoustic lag times between the arrays corresponds well to modelled values, based on full-wave modelling through best-known oceanic models.","Atlantic Ocean; Interferometry; Acoustic properties; Wave propagation","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:61610d9a-db9e-44ef-aa18-a4b178fb620c","http://resolver.tudelft.nl/uuid:61610d9a-db9e-44ef-aa18-a4b178fb620c","Up-Down Wavefields Reconstruction in Boreholes Using Single-Component Data","Liu, Y. (Norwegian University of Science and Technology); Arntsen, B (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","A standard procedure in processing vertical seismic profile (VSP) data is the separation of up-and downgoing wavefields. We show that the up-down wavefields in boreholes can be reconstructed using only singlecomponent borehole data, given that a full set of surface reflection data is also available. No medium parameters are required. The method is wave-equation based for a general inhomogeneous lossless medium with moderately curved interfaces. It relies on a focusing wavefield from the Marchenko method, which gives the recipe for finding this wavefield that satisfies certain focusing conditions in a reference medium. The up-down wavefields are then reconstructed at borehole positions using this focusing wavefields and the surface reflection response. We show that the method is applicable to boreholes with any general orientation. The requirement is that the source positions in the surface data are regularized to be the same as those in the borehole data, and that source deconvolution and surface multiple removal are applied for the surface data. Numerical results from a field in the North Sea are shown, and three different borehole geometries (horizontal, deviated and vertical) are tested. The result shows that the reconstructed up-down wavefields agree well with those by conventional separation methods.","","en","conference paper","EAGE","","","","","","","2018-06-01","","","Applied Geophysics and Petrophysics","","","" "uuid:8517ffa7-2f28-48f6-bb96-fe93885541fe","http://resolver.tudelft.nl/uuid:8517ffa7-2f28-48f6-bb96-fe93885541fe","Velocity analysis using surface-seismic primaries-only data obtained without removing multiples","Dokter, E. (University of Edinburgh); Meles, G.A. (TU Delft Applied Geophysics and Petrophysics; University of Edinburgh); Curtis, A (University of Edinburgh); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","A number of seismic processing methods, including velocity analysis (Sheriff and Geldart, 1999), make the assumption that recorded waves are primaries - that they have scattered only once (the Born approximation). Multiples then represent a source of coherent noise and must be suppressed to avoid artefacts. There are different approaches to mitigate free surface multiples (see Dragoset et al. (2010) for an overview), but internal multiples still pose a problem and usually cannot be removed without high computational cost or knowledge of the medium. Recently, Marchenko redatuming has been developed to image a medium in the presence of internal multiples (Wapenaar et al., 2014). Using Marchenko redatuming in combination with convolutional interferometry, Meles et al. (2016) have developed a method which allows the construction of a primaries-only data set from existing seismic reflection data and an initial velocity model. The method was proposed for the acoustic case and appears to be robust with respect to even huge inaccuracies in the employed velocity model. In this paper we investigate the impact of such primaries-only data on a simple velocity analysis workflow, as opposed to using the full data set with multiples. We use semblance analysis (Sheriff and Geldart, 1999) and compare the results obtained with three different data sets: the full reflection data with multiples, primaries data calculated with prior knowledge of the subsurface, and primaries data calculated with an entirely incorrect constant velocity model. We then use the velocity models that we construct to perform reverse time migration (RTM) of each of the data sets. We find that the velocities found are robust with respect to errors in the initial model used for Marchenko redatuming, and the method produces good results if non-hyperbolic moveout effects are avoided.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:7226c2a4-f516-4b3c-aaed-1d2ea7da0ab2","http://resolver.tudelft.nl/uuid:7226c2a4-f516-4b3c-aaed-1d2ea7da0ab2","On the role of multiples in Marchenko imaging","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2017","","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:a6b425da-d877-43c1-ac28-8c1b3cd54f09","http://resolver.tudelft.nl/uuid:a6b425da-d877-43c1-ac28-8c1b3cd54f09","Accounting for free-surface multiples in Marchenko imaging","Singh, S.; Snieder, R; van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","Imagine placing a receiver at any location in the earth and recording the response at that location to sources on the surface. In such a world, we could place receivers around our reservoir to better image the reservoir and understand its properties. Realistically, this is not a feasible approach for understanding the subsurface. We have developed an alternative and realizable approach to obtain the response of a buried virtual receiver for sources at the surface. Our method is capable of retrieving the Green’s function for a virtual point in the subsurface to the acquisition surface. In our case, a physical receiver is not required at the subsurface point; instead, we require the reflection measurements for sources and receivers at the surface of the earth and a macromodel of the velocity (no small-scale details of the model are necessary). We can interpret the retrieved Green’s function as the response to sources at the surface for a virtual receiver in the subsurface. We obtain this Green’s function by solving the Marchenko equation, an integral equation pertinent to inverse scattering problems. Our derivation of the Marchenko equation for the Green’s function retrieval takes into account the free-surface reflections present in the reflection response (previous work considered a response without free-surface multiples). We decompose the Marchenko equation into up- and downgoing fields and solve for these fields iteratively. The retrieved Green’s function not only includes primaries and internal multiples as do previous methods, but it also includes freesurface multiples. We use these up- and downgoing fields to obtain a 2D image of our area of interest, in this case, below a synclinal structure.","","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","","" "uuid:6f56a5a1-f320-4b0e-8ae7-d4eada60ca08","http://resolver.tudelft.nl/uuid:6f56a5a1-f320-4b0e-8ae7-d4eada60ca08","Theory for Marchenko imaging of marine seismic data with free surface multiple elimination","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","The theory of data-driven true amplitude migration is presented for multicomponent marine seismic data. The Marchenko scheme is adapted to account for the ghost, free surface and internal multiple effects and works without the need to know the source wavelet. A true amplitude image is formed from the obtained focusing functions without ghost effects and artefacts from free surface and internal multiples. The resulting reflectivity at image times can be input for a final step of full waveform inversion. The numerical example shows the effectiveness of the method in a simple 1D problem.","","en","conference paper","EAGE","","","","","","","2018-01-01","","","Applied Geophysics and Petrophysics","","","" "uuid:8b5b6fd7-8a4a-468c-91dd-77f6a3627a2e","http://resolver.tudelft.nl/uuid:8b5b6fd7-8a4a-468c-91dd-77f6a3627a2e","Snapshot wavefield decomposition for heterogeneous velocity media","Holicki, M.E. (TU Delft Applied Geophysics and Petrophysics); Drijkoningen, G.G. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","We propose a novel directional decomposition operator for wavefield snapshots in heterogeneous-velocity media. The proposed operator demonstrates the link between the amplitude of pressure and particlevelocity plane waves in the wavenumber domain. The proposed operator requires two spatial Fourier transforms (one forward and one backward) per spatial dimension and time slice. To illustrate the operator we demonstrate its applicability to heterogeneous velocity models using a simple velocity-box model and a more heterogeneous velocity model, based on real data, from close to the Annerveen gas field, The Netherlands.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:c3eb7eb2-27cf-43ae-8d99-0ae92fd057b0","http://resolver.tudelft.nl/uuid:c3eb7eb2-27cf-43ae-8d99-0ae92fd057b0","Why multiples do not contribute to deconvolution imaging","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2017","The question whether multiples are signal or noise is subject of ongoing debate. In this paper we consider correlation and deconvolution imaging methods and analyse to what extent multiples contribute to the image in these methods. Our starting point is the assumption that at a specific depth level the full downgoing and upgoing fields (both including all multiples) are available. First we show that by cross correlating the full downgoing and upgoing wave fields, primaries and multiples contribute to the image. This image is not true-amplitude and is contaminated by cross-talk artefacts. Next we show that by deconvolving the full upgoing field by the full downgoing field, multiples do not contribute to the image. We use minimum-phase arguments to explain this somewhat counterintuitive conclusion. The deconvolution image is true-amplitude and not contaminated by cross-talk artefacts. The conclusion that multiples do not contribute to the image applies to the type of deconvolution imaging analysed in this paper, but should not be extrapolated to other imaging methods. On the contrary, much research is dedicated to using multiples for imaging, for example in full wavefield migration, resonant migration and Marchenko imaging.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:b1b4381d-7219-40b9-84e7-6d7fb8a6120a","http://resolver.tudelft.nl/uuid:b1b4381d-7219-40b9-84e7-6d7fb8a6120a","Sparse Inversion for Solving the Coupled Marchenko Equations Including Free-surface Multiples","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Grobbe, N. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","We compare the coupled Marchenko equations without free-surface multiples to the coupled Marchenko equations including free-surface multiples. When using the conventional method of iterative substitution to solve these equations, a difference in convergence behaviour is observed, suggesting that there is a fundamental difference in the underlying dynamics. Both an intuitive explanation, based on an interferometric interpretation, as well as a mathematical explanation, confirm this difference, and suggest that iterative substitution might not be the most suitable method for solving the system of equations including free-surface multiples. Therefore, an alternative method is required. We propose a sparse inversion, aimed at solving an under-determined system of equations. Results show that the sparse inversion is indeed capable of correctly solving the coupled Marchenko equations including free-surface multiples, even when the iterative scheme fails. Using sparsity promotion and additional constraints, it is expected to perform better than iterative substitution when working with incomplete data or in the presence of noise. Also, simultaneous estimation of the source wavelet is a potential possibility.","","en","conference paper","EAGE","","","","","","","2017-12-31","","","Applied Geophysics and Petrophysics","","","" "uuid:f12f14ab-7ad4-425c-8335-38daea5dce1d","http://resolver.tudelft.nl/uuid:f12f14ab-7ad4-425c-8335-38daea5dce1d","Time-lapse data prediction by Marchenko-based reservoir transplantation","Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","In a time-lapse experiment, changes in a reservoir cause changes in the reflection response. We discuss a method which predicts these changes from the baseline survey and a model of the changed reservoir. This method, which takes all multiple

scattering into account, is significantly more efficient than modeling the response of the entire medium containing the changed reservoir. This can be particularly attractive for applications in time-lapse full wave form inversion, which requires

repeated modelling of the reflection response.","","en","conference paper","SEG","","","","","","","","","","","","","" "uuid:81609a44-8217-47db-b672-2302af612d40","http://resolver.tudelft.nl/uuid:81609a44-8217-47db-b672-2302af612d40","Adaptive double-focusing method for source-receiver Marchenko redatuming on field data","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Pereira, R (CGG); Douma, H; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","We present an adaptive double-focusing method for applying source-receiver Marchenko redatuming to field data. Receiver redatuming is achieved by a first focusing step, where the coupled Marchenko equations are iteratively solved for the oneway Green’s functions. Next, source redatuming is typically performed by a multi-dimensional deconvolution of these Green’s functions. Instead, we propose a second focusing step for source Marchenko redatuming, using the upgoing Green’s function and the downgoing focusing function to obtain a redatumed reflection response in the physical medium. This method makes adaptive processing more straight-forward, making it less sensitive to imperfections in the data and the acquisition geometry and more suitable for the application to field data. In addition, it is cheaper and can be parallelized by pair of focal points.","","en","conference paper","SEG","","","","","","","","","","","","","" "uuid:95b79ea8-bb03-41d3-8dea-96bdabc8bd41","http://resolver.tudelft.nl/uuid:95b79ea8-bb03-41d3-8dea-96bdabc8bd41","Deconvolution and correlation-based interferometric redatuming by wavefield inversion","Barrera Pacheco, D.F.; Schleicher, J.; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","Seismic interferometry is a method to retrieve Green’s functions for sources (or receivers) where there are only receivers (or sources, respectively). This can be done by correlationor deconvolution-based methods. In this work we present a

new approach to reposition the seismic array from the earth’s surface to an arbitrary datum at depth using the one-way reciprocity theorems of convolution and correlation type. The redatuming process is done in three steps: (a) retrieving the downward Green’s function for sources at the earth’s surface

and receivers at the datum, (b) retrieving the corresponding upward Green’s function, and (c) retrieving the reflected upward wavefield for sources and receivers at the datum. Input for steps (a) and (b) are the surface data and wavefields simulated in a velocity model of the datum overburden. Step (c)

uses the responses of steps (a) and (b) as input data in the convolution-based interferometric equation. The method accounts for inhomogeneities in the overburden medium, thus reducing anticausal events and artefacts as compared to a purely correlation-based procedure.","","en","conference paper","SEG","","","","","","","","","","","","","" "uuid:65a6e1bc-fd87-4944-82d3-6551b2d973a2","http://resolver.tudelft.nl/uuid:65a6e1bc-fd87-4944-82d3-6551b2d973a2","Obtaining local reflectivity at two-way travel time by filtering acoustic reflection data","Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Zhang, L. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","A modified implementation of Marchenko redatuming leads to a filter that removes internal multiples from reflection data. It produces local reflectivity at two-way travel time. The method creates new primary reflections resulting from emitted events that eliminate internal multiples. We call these non-physical

primaries and their presence is a disadvantage. The advantage is that the filter is model free. We give the 3D filter and demonstrate with 1D arguments that starting the focusing wavefield with a unit impulse at zero time, while focusing below the bottom reflector, is the choice that leads to a model free implementation. The starting impulse generates the reflection data. Every later emitted pulse eliminates an internal multiple somewhere in the model and helps removing the transmission

amplitude effects in a physical primary. We show that

the amplitude of the non-physical primaries are a product of

three reflections, making them generally smaller than those of

the physical primaries. A 2D modeled shotgather at different

stages of filtering the data shows that the filter works well.","","en","conference paper","SEG","","","","","","","","","","","","","" "uuid:6990bd1b-f669-4dc0-ae21-5cf98c0261f4","http://resolver.tudelft.nl/uuid:6990bd1b-f669-4dc0-ae21-5cf98c0261f4","Decomposition of the Green's function using the Marchenko equation","Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","Mihai Popovici, A. (editor); Fomel, S. (editor)","2017","The Marchenko equation can be used to retrieve the Green’s function at depth as a full function or decomposed into its upand downgoing parts. We show that the equation can be rewritten to create a decomposition scheme that can decompose a full wavefield, that was recorded at depth, into its up- and downgoing parts. We show that this can be done without a smooth velocity model that the Marchenko scheme requires and without any knowledge of the medium properties that traditional decomposition methods require. Instead we only need a the reflection response and a wavefield that has been recorded at the

surface due to a source at depth or (by using source-receiver reciprocity) that was measured down in a borehole due to a source at the surface. We also validate our results by comparing them to directly modeled up- and downgoing wavefields.","","en","conference paper","SEG","","","","","","","","","","","","","" "uuid:15993158-7871-409b-bb47-c941ef170a41","http://resolver.tudelft.nl/uuid:15993158-7871-409b-bb47-c941ef170a41","Reflecting boundary conditions for interferometry by multidimensional deconvolution: invited paper","Weemstra, C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); van Dalen, K.N. (TU Delft Applied Mechanics)","","2017","Seismic interferometry (SI) takes advantage of existing (ambient) wavefield recordings by turning receivers into so-called “virtual-sources.” The medium’s response to these virtual sources can be harnessed to image that medium. Applications of SI include surface-wave imaging of the Earth’s shallow subsurface and medical imaging. Most interferometric applications, however, suffer from the fact that the retrieved virtual-source responses deviate from the true medium responses. The accrued artifacts are often predominantly due to a non-isotropic illumination of the medium of interest, and prohibit accurate interferometric imaging. Recently, it has been shown that illumination-related artifacts can be removed by means of a so-called multidimensional deconvolution (MDD) process. However, The current MDD formulation, and hence method, relies on separation of waves traveling inward and outward through the boundary of the medium of interest. As a consequence, it is predominantly useful when receivers are illuminated from one side only. This puts constraints on the applicability of the current MDD formulation to omnidirectional wavefields. We present a modification of the formulation of the theory underlying SI by MDD. This modification eliminates the requirement to separate inward-and outward propagating wavefields and, consequently, holds promise for the application of MDD to non-isotropic, omnidirectional wavefields","","en","journal article","","","","","","","","2018-05-01","","","","","","" "uuid:ec71f4f1-35ac-49e6-a1d9-889e36a2f831","http://resolver.tudelft.nl/uuid:ec71f4f1-35ac-49e6-a1d9-889e36a2f831","Application of seismic interferometry by multidimensional deconvolution to ambient seismic noise recorded in Malargüe, Argentina","Weemstra, C. (TU Delft Applied Geophysics and Petrophysics; Utrecht University); Draganov, D.S. (TU Delft Applied Geophysics and Petrophysics); Ruigrok, E.N. (Royal Netherlands Meteorological Institute; Utrecht University); Hunziker, J.W. (University of Lausanne); Gomez, Martin (Comision Nacional de Energia Atomica); Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2017","Obtaining new seismic responses from existing recordings is generally referred to as seismic interferometry (SI). Conventionally, the SI responses are retrieved by simple crosscorrelation of recordings made by separate receivers: one of the receivers acts as a ‘virtual source’ whose response is retrieved at the other receivers.When SI is applied to recordings of ambient seismic noise, mostly surface waves are retrieved. The newly retrieved surface wave responses can be used to extract receiver-receiver phase velocities. These phase velocities often serve as input parameters for tomographic inverse problems. Another application of SI exploits the tempo- ral stability of the multiply scattered arrivals of the newly retrieved surface wave responses. Temporal variations in the stability and/or arrival time of these multiply scattered arrivals can often be linked to temporally varying parameters such as hydrocarbon production and precip- itation. For all applications, however, the accuracy of the retrieved responses is paramount. Correct response retrieval relies on a uniform illumination of the receivers: irregularities in the illumination pattern degrade the accuracy of the newly retrieved responses. In practice, the illumination pattern is often far from uniform. In that case, simple crosscorrelation of separate receiver recordings only yields an estimate of the actual, correct virtual-source response. Re- formulating the theory underlying SI by crosscorrelation as a multidimensional deconvolution (MDD) process, allows this estimate to be improved. SI by MDD corrects for the non-uniform illumination pattern by means of a so-called point-spread function (PSF), which captures the irregularities in the illumination pattern. Deconvolution by this PSF removes the imprint of the irregularities on the responses obtained through simple crosscorrelation. We apply SI by MDD to surface wave data recorded by theMalargue seismic array in western Argentina. The aperture of the array is approximately 60 km and it is located on a plateau just east of the Andean mountain range. The array has a T-shape: the receivers along one of the two lines act as virtual sources whose responses are recorded by the receivers along the other (perpendicular) line.We select time windows dominated by surface wave noise travelling in a favourable direction, that is, traversing the line of virtual sources before arriving at the receivers at which we aim to retrieve the virtual-source responses. These time windows are selected through a frequency-dependent slowness analysis along the two receiver lines. From the selected time windows, estimates of virtual-source responses are retrieved by means of crosscorrelations. Similarly, crosscorrelations between the positions of the virtual sources are computed to build the PSF. We use the PSF to deconvolve the effect of illumination irregularities and the source function from the virtual-source responses retrieved by crosscorrelation. The combined effect of time-window selection and MDD results in more accurate and temporally stable surface wave responses.","Broad-band seismometers; Seismic monitoring and test-ban treaty verification; Surfacewaves and free oscillations; Interfacewaves; Seismic attenuation; Seismic tomography","en","journal article","","","","","","","","","","","","","","" "uuid:2cc566bf-9d49-43b6-8abb-bdb6e2d4bcbd","http://resolver.tudelft.nl/uuid:2cc566bf-9d49-43b6-8abb-bdb6e2d4bcbd","Applying source-receiver Marchenko redatuming to field data, using an adaptive double-focusing method","Staring, M. (TU Delft Applied Geophysics and Petrophysics); Pereira, Roberto (CGG, Rio de Janeiro); Douma, Huub; van der Neut, J.R. (TU Delft ImPhys/Acoustical Wavefield Imaging); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","In this paper, we focus on the field data application of source-receiver Marchenko redatuming. Conventionally, a source-receiver redatumed reflection response is obtained by first applying the Marchenko method for receiver-redatuming and then performing a multi-dimensional deconvolution (MDD) for sourceredatuming (Wapenaar et al. (2014)). The obtained reflection response is free from any interactions with the overburden. However, the MDD solves an ill-posed inverse problem (van der Neut et al. (2011a)), which makes it sensitive to imperfections in the data and the acquisition geometry. This is a problem for the field data application, since neither the data nor the acquisition geometry are ever perfect. In addition, MDD is computationally expensive.","","en","conference paper","","","","","","","","","","","","","","" "uuid:0b3a6327-387d-4d8a-97d3-92d0c0340f9f","http://resolver.tudelft.nl/uuid:0b3a6327-387d-4d8a-97d3-92d0c0340f9f","Homogeneous Green’s function retrieval using the Marchenko method","Brackenhoff, J.A. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2017","In wave theory, a Green’s function is defined as the response of a medium to an impulsive point source. The homogeneous Green’s function is the combination of the Green’s function and its time-reversal. Homogeneous Green’s functions can be retrieved if the medium is enclosed by a boundary where the full wavefield is recorded. In recent years, the Marchenko method has gained popularity, because unlike many conventional methods it does not require an enclosing boundary. Instead a single-sided boundary is all that is required. The method is sensitive to attenuation, which makes it difficult to apply to field data. We will show that by using corrections on the attenuated data, we can retrieve the Green’s functions in the subsurface. These results can be visualized in order to see how the wavefield propagates through the subsurface.

by separate receivers: a first receiver acts as a 'virtual source' whose response is retrieved at the other receivers. When surface waves are retrieved, the newly retrieved responses can be used to extract receiver-receiver phase velocities. These phase velocities often serve as input parameters for tomographic inverse problems. Another application of SI exploits the temporal stability of the multiply scattered arrivals (the coda). For all applications, however, the accuracy of the retrieved responses is paramount. In practice, this accuracy is often degraded by irregularities in the illumination pattern: correct response retrieval relies on a uniform illumination of the receivers. Reformulating the theory underlying seismic interferometry by crosscorrelation as a multidimensional deconvolution (MDD) process, allows for correction of these non-uniform illumination patterns by means of a so-called point-spread function (PSF). We apply SI by MDD to surface-wave data recorded by the Malargüe seismic array in western Argentina. The aperture of the array is approximately 60 km and it is located on a plateau just east of the Andean mountain range. The array has a T-shape, which makes it very well suited for the application of SI by MDD. We select time windows dominated by surface-wave noise traveling in a favorable direction, that is, traversing the line of virtual sources before arriving at the receivers at which we aim to retrieve the virtual-source responses. These time windows are selected based upon the slownesses along the two receiver lines. From the selected time windows, virtual-source responses are retrieved by computation of ensemble-averaged crosscorrelations. Similarly, ensemble-averaged crosscorrelations between the positions of the virtual sources are computed: the PSF. We use the PSF to deconvolve the effect of illumination irregularities and the source function from the virtual-source responses retrieved by crosscorrelation. The combined effect of time-window selection and MDD results in more accurate and temporally stable surface-wave responses.","","en","abstract","","","","","","","Campus only","","","","","","","" "uuid:4df9ab66-7358-4539-b392-b43c09013030","http://resolver.tudelft.nl/uuid:4df9ab66-7358-4539-b392-b43c09013030","Estimating the location of a tunnel using interferometric times of Rayleigh-wave scattering","Kaslilar, A.; Harmankaya, U.; Wapenaar, C.P.A.; Draganov, D.S.","","2015","Inspired by a technique called seismic interferometry, we estimate the location of a scatterer using scattered waves. We isolate the scattered wavefield and evaluate the result of correlating scattered waves at different receiver locations. The cross-correlation eliminates the travel path between a source and a scatterer, making the estimation of the scatterers’ locations dependent only on properties between the receivers and the scatterer. We illustrate the potential of this method by locating a tunnel from seismic 23 field data, recorded along a line with multiple source and receiver locations. As near-surface scatterers are potential weak zones and may pose risk for the environment, to mitigate geo- and environmental hazards, this method can be an efficient alternative in detection of such structures.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:64f2fc04-f957-410d-bc10-a7b285ef4f06","http://resolver.tudelft.nl/uuid:64f2fc04-f957-410d-bc10-a7b285ef4f06","Creating virtual receivers from drill-bit noise","Liu, Y.; Draganov, D.S.; Wapenaar, C.P.A.; Arntsen, B.","","2015","In the field of seismic interferometry using noise, surface waves and body waves between receivers have been retrieved by crosscorrelating recordings of uncorrelated noise sources to extract useful subsurface information. When the positions of the noise sources are known, inter-source interferometry can be applied to retrieve the wavefileds between sources, thus turning sources into virtual receivers. Previous applications of this form of interferometry assume impulsive point sources or transient sources with similar signatures. We investigate the requirements of applying inter-source seismic interferometry using drill-bit noise to retrieve the reflection responses at those positions. We show that an accurate estimate of the source function is essential for such application. The preprocessing involves using standard seismicwhile-drilling procedures, such as pilot crosscorrelation and pilot deconvolution to remove the drill-bit signatures in the data, and then applying crosscorrelation interferometry. Provided that pilot signals are reliable, drill-bit data can be redatumed from surface to the depth of boreholes using this inter-source interferometry approach without any velocity information of the medium. We show that a well-positioned image below the borehole can be obtained with just a simple velocity model using these reflection responses. We also discuss some of the practical hurdles that restrict its application offshore.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:4f470bea-639d-49be-af8d-fa3556691801","http://resolver.tudelft.nl/uuid:4f470bea-639d-49be-af8d-fa3556691801","Reflection imaging of the Moho and the aseismic Nazca slab in the Malargüe region with global-phase seismic interferometry; abstract","Nishitsuji, Y.; Draganov, D.S.; Ruigrok, E.; Gomez, M.; Wapenaar, C.P.A.","","2015","","","en","conference paper","AGU","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","","","" "uuid:d70af4b3-b5b7-40e6-b1bc-0a7b08880bac","http://resolver.tudelft.nl/uuid:d70af4b3-b5b7-40e6-b1bc-0a7b08880bac","Seismic reflection imaging, accounting for primary and multiple reflections","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Broggini, F.; Slob, E.C.; Snieder, R.","","2015","","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","","","" "uuid:5c46a3e3-4341-4689-8500-0d2408cda5df","http://resolver.tudelft.nl/uuid:5c46a3e3-4341-4689-8500-0d2408cda5df","Reflecting boundary conditions for interferometry by multidimensional deconvolution","Weemstra, C.; Wapenaar, C.P.A.; Van Dalen, K.N.","","2015","In this work we investigate a modification of the formulation of the theory underlying seismic interferometry (SI) by multidimensional deconvolution (MDD). The current formulation, and hence method, relies on separation of waves traveling inward and outward of a volume bounded by receivers. As a consequence, it is predominantly useful when receivers are illuminated from one side only. This puts constraints on the applicability of SI by MDD to omnidirectional wave fields. The proposed modification eliminates the requirement to separate inward-and outward propagating wave field and, consequently, improves the applicability of MDD to omnidirectional wave fields. We therefore envisage the modified MDD formulation to hold significant promise in the application to ambient-noise surface wave data.","illumination; deconvolution; passive; surface wave","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:26d929d6-05b8-4583-b13b-6a2fa0ef35fb","http://resolver.tudelft.nl/uuid:26d929d6-05b8-4583-b13b-6a2fa0ef35fb","Imaging and monitoring of subsurface structures using reflection retrieves from seismic interferometry","Draganov, D.S.; Wapenaar, C.P.A.","","2015","","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:ef15255e-c92c-4615-bd63-b9525f7e25db","http://resolver.tudelft.nl/uuid:ef15255e-c92c-4615-bd63-b9525f7e25db","Marchenko imaging: Imaging with primaries, internal multiples, and free-surface multiples","Singh, S.; Snieder, R.; Behura, J.; van der Neut, J.R.; Wapenaar, C.P.A.; Slob, E.C.","","2015","Recent work on retrieving the Green’s function with the Marchenko equation shows how these functions for a virtual source in the subsurface can be obtained from reflection data. The response to the virtual source is the Green’s function from the location of the virtual source to the surface. The Green’s function is retrieved using only the reflection response of the medium and an estimate of the first arrival at the surface from the virtual source. Current techniques, however, only include primaries and internal multiples. Therefore, all surface-related multiples must be removed from the reflection response prior to Green’s function retrieval. We have extended the Marchenko equation to retrieve the Green’s function that includes primaries, internal multiples, and free-surface multiples. In other words, we have retrieved the Green’s function in the presence of a free surface. The information needed for the retrieval is the same as the current techniques, with the only difference being that the reflection response now also includes free-surface multiples. The inclusion of these multiples makes it possible to include them in the imaging operator, and it obviates the need for surface-related multiple elimination. This type of imaging with Green’s functions is called Marchenko imaging.","multiples; scattering; imaging; reflectivity; reciprocity","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:54461b72-390d-4755-ad4d-51a80c1bd352","http://resolver.tudelft.nl/uuid:54461b72-390d-4755-ad4d-51a80c1bd352","Geophysical noise interferometry: Repairing the broken mirror","Wapenaar, C.P.A.; Van der Neut, J.R.; Draganov, D.S.","","2015","Under conditional circumstances, the correlation of noise at two receivers is approximately proportional to the Green’s function between these receivers. Hence, the correlation process turns one of the receivers into a virtual source, of which the response is observed by the other receiver. This principle, also known as ambient-noise interferometry, is used by researchers in geophysics, ultrasonics and underwater acoustics to infer information about an unknown object from passive noise measurements. In geophysics, ambient-noise interferometry is used for tomographic velocity inversion when surface waves are dominant, or for high-resolution reflection imaging when a significant amount of body waves is present in the noise field. The virtual-source response obtained with geophysical noise interferometry is accurate when the medium is lossless and the noise field is equipartitioned. In practice these assumptions are often violated: the medium of interest is often illuminated from one side only, the sources may be irregularly distributed and losses may be significant. For those cases, it is as if the virtual source is viewed in a broken (time-reversal) mirror, which causes blurring of the source. This blurring is quantified by the so-called point-spread function, which, like the correlation function, can be derived from the observed data (that is, without the need to know the actual sources and the medium). The broken mirror can be repaired by deconvolving the correlation function for the point-spread function. As a result, the virtual source is refocused and hence the virtual-source response becomes more reliable.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:835a8461-b853-46e4-9a70-7d8e19a95485","http://resolver.tudelft.nl/uuid:835a8461-b853-46e4-9a70-7d8e19a95485","An illustration of adaptive Marchenko imaging","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Slob, E.C.; Vasconcelos, I.","","2015","In Marchenko imaging, wavefields are retrieved at specified focal points in the subsurface through an iterative scheme derived from the multidimensional Marchenko equation. The method requires seismic-reflection data at the earth’s surface (after free-surface multiple elimination) and an estimate of the direct wavefield from the surface to each focal point, which can be computed, for instance, in a macrovelocity model. In the first iteration, the direct wavefield is crosscorrelated with the reflection data. This operation is identical to inverse-wavefield extrapolation as is applied commonly in various imaging schemes, for instance, in reverse time migration (RTM). At each succeeding iteration, the result of the previous iteration is truncated in time and crosscorrelated with the reflection data again. To obtain a seismic image, a multidimensional deconvolution-based imaging condition can be applied to the retrieved wavefields. By this approach, both primary reflections and internal multiples contribute to the construction of the image. Alternatively, a crosscorrelation-based imaging condition can be used in which only the primary reflections are imaged and the contributions of internal multiples are subtracted. The latter strategy offers more flexibility because the subtraction of redatumed internal multiples can be implemented adaptively. Through this approach, the artifacts from internal multiples can be removed effectively from a conventional RTM image.","","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f5b72d69-b9ee-4e27-be15-3751a68ca753","http://resolver.tudelft.nl/uuid:f5b72d69-b9ee-4e27-be15-3751a68ca753","Inversion of the multidimensional marchenko equation","Van der Neut, J.R.; Thorbecke, J.W.; Wapenaar, C.P.A.; Slob, E.C.","","2015","Focusing functions are defined as wavefields that focus at a specified location in a heterogeneous subsurface. These functions can be directly related to Green's functions and hence they can be used for seismic imaging of complete wavefields, including not only primary reflections but all orders of internal multiples. Recently, it has been shown that focusing functions can be retrieved from single-sided reflection data and an initial operator (which can be computed in a smooth background velocity model of the subsurface) by iterative substitution of the multidimensional Marchenko equation. In this work, we show that the Marchenko equation can also be inverted directly for the focusing functions. Although this approach is computationally more expensive than iterative substitution, additional constraints can easily be imposed. Such a flexibility might be beneficial in specific cases, for instance when the recorded data are incomplete or when additional measurements (e.g. from downhole receivers) are available.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:d3a88b74-a158-4df2-ae3a-9bb8bc5b6cf6","http://resolver.tudelft.nl/uuid:d3a88b74-a158-4df2-ae3a-9bb8bc5b6cf6","Estimating the location of scatterers using correlation of scattered rayleigh waves","Harmankaya, U.; Kaslilar, A.; Van Wijk, K.; Wapenaar, C.P.A.; Draganov, D.S.","","2015","Inspired by a technique called seismic interferometry, we estimate the location of scatterers in a scaled model, where many near-surface scatterers are present. We isolate the scattered wavefield and evaluate correlation of scattered waves at different receiver locations. The cross-correlation eliminates the travel path between a source and a scatterer, making the estimation of the scatterers’ locations dependent only on properties between the receivers and the scatterer. We illustrate the potential of this method by locating scatterers with ultrasonic laboratory measurements of scattered Rayleigh waves recorded on two parallel and orthogonal lines of receivers. As near-surface scatterers are potential weak zones and may pose risk for the environment, to mitigate geo and environmental hazards, this method can be an efficient alternative that can be used in detection of such structures.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6d234427-0934-4f86-8f18-c17a4045293d","http://resolver.tudelft.nl/uuid:6d234427-0934-4f86-8f18-c17a4045293d","Elastodynamic Marchenko focusing, green's function retrieval and imaging","Wapenaar, C.P.A.; Slob, E.C.","","2015","Building on acoustic autofocusing in 1D media, we previously proposed acoustic Marchenko imaging for 1D and 3D media. Recently, the first steps have been set towards extending the single-sided Marchenko method to the elastodynamic situation. Here we discuss the extension of single-sided Marchenko focusing, Green's function retrieval and imaging to the elastodynamic situation. With numerical examples in a horizontally layered medium we show that, at least in principle, a true amplitude image can be obtained, free of artefacts related to multiple reflections and wave conversions. The method can be extended to 3D situations, in a similar way as we extended the acoustic 1D method to the 3D situation.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f2a1c814-5fa3-49a9-8257-7244c2d46f68","http://resolver.tudelft.nl/uuid:f2a1c814-5fa3-49a9-8257-7244c2d46f68","Retrieving surface waves from ambient seismic noise using seismic interferometry by multidimensional deconvolution","Van Dalen, K.N.; Mikesell, T.D.; Ruigrok, E.N.; Wapenaar, C.P.A.","","2015","Retrieving virtual source surface waves from ambient seismic noise by cross correlation assumes, among others, that the noise field is equipartitioned and the medium is lossless. Violation of these assumptions reduces the accuracy of the retrieved waves. A point-spread function computed from the same ambient noise quantifies the associated virtual source's spatial and temporal smearing. Multidimensional deconvolution (MDD) of the retrieved surface waves by this function has been shown to improve the virtual source's focusing and the accuracy of the retrieved waves using synthetic data. We tested MDD on data recorded during the Batholiths experiment, a passive deployment of broadband seismic sensors in British Columbia, Canada. The array consisted of two approximately linear station lines. Using 4 months of recordings, we retrieved fundamental-mode Rayleigh waves (0.05–0.27 Hz). We only used noise time windows dominated by waves that traverse the northern line before reaching the southern (2.5% of all data). Compared to the conventional cross-correlation result based on this subset, the MDD waveforms are better localized and have significantly higher signal-to-noise ratio. Furthermore, MDD corrects the phase, and the spatial deconvolution fills in a spectral (f, k domain) gap between the single-frequency and double-frequency microseism bands. Frequency whitening of the noise also fills the gap in the cross-correlation result, but the signal-to-noise ratio of the MDD result remains higher. Comparison of the extracted phase velocities shows some differences between the methods, also when all data are included in the conventional cross correlation.","","en","journal article","American Geophysical Union","","","","","","","2015-08-06","Civil Engineering and Geosciences","Structural Engineering","","","","" "uuid:c27b50de-0d8a-4a8c-923d-a64633ec9568","http://resolver.tudelft.nl/uuid:c27b50de-0d8a-4a8c-923d-a64633ec9568","On Green’s function retrieval by iterative substitution of the coupled Marchenko equations","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2015","Iterative substitution of the coupled Marchenko equations is a novel methodology to retrieve the Green's functions from a source or receiver array at an acquisition surface to an arbitrary location in an acoustic medium. The methodology requires as input the single-sided reflection response at the acquisition surface and an initial focusing function, being the time-reversed direct wavefield from the acquisition surface to a specified location in the subsurface. We express the iterative scheme that is applied by this methodology explicitly as the successive actions of various linear operators, acting on an initial focusing function. These operators involve multidimensional crosscorrelations with the reflection data and truncations in time. We offer physical interpretations of the multidimensional crosscorrelations by subtracting traveltimes along common ray paths at the stationary points of the underlying integrals. This provides a clear understanding of how individual events are retrieved by the scheme. Our interpretation also exposes some of the scheme's limitations in terms of what can be retrieved in case of a finite recording aperture. Green's function retrieval is only successful if the relevant stationary points are sampled. As a consequence, internal multiples can only be retrieved at a subsurface location with a particular ray parameter if this location is illuminated by the direct wavefield with this specific ray parameter. Several assumptions are required to solve the Marchenko equations. We show that these assumptions are not always satisfied in arbitrary heterogeneous media, which can result in incomplete Green's function retrieval and the emergence of artefacts. Despite these limitations, accurate Green's functions can often be retrieved by the iterative scheme, which is highly relevant for seismic imaging and inversion of internal multiple reflections.","controlled source seismology; wave scattering and diffraction","en","journal article","Oxford University Press","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6debab43-6c38-48ce-acb7-55cbae48f654","http://resolver.tudelft.nl/uuid:6debab43-6c38-48ce-acb7-55cbae48f654","A method to retrieve an improved high resolution reflection response from HiCLIMB array recordings of local earthquake scattering coda (PPT)","Hartstra, I.E. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2015","We discuss a method to interferometrically retrieve the body wave reflection response from local high-frequency scattering coda wave fields with the purpose to obtain an input dataset suitable for the application of advanced exploration-type imaging methods","scattering coda; interferometry; scattering mean free path; reflection response; impedance contrasts; advanced exploration-type imaging; coda attenuation factor; HiCLIMB array","en","conference paper","","","","","","","","","","","","","","" "uuid:f7957d42-8910-49eb-8ba5-5bd98374ea00","http://resolver.tudelft.nl/uuid:f7957d42-8910-49eb-8ba5-5bd98374ea00","The life cycle of a Sudden Stratospheric Warming from infrasonic ambient noise observations","Smets, P.; Evers, L.G.; Wapenaar, C.P.A.","","2014","","","en","journal article","EGU","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6d0ac8a1-3880-4df6-bfb4-d4b96563284a","http://resolver.tudelft.nl/uuid:6d0ac8a1-3880-4df6-bfb4-d4b96563284a","Creating virtual vertical radar profiles from surface reflection ground penetrating radar data","Slob, E.C.; Hunziker, J.W.; Thorbecke, J.W.; Wapenaar, C.P.A.","","2014","","virtual source; virtual receiver; interferometry; autofocusing; 3D GPR","en","conference paper","UCL , COST","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5c923f77-d6d2-470d-bda6-08d1dff30b80","http://resolver.tudelft.nl/uuid:5c923f77-d6d2-470d-bda6-08d1dff30b80","Single-sided Marchenko focusing of compressional and shear waves","Wapenaar, C.P.A.","","2014","In time-reversal acoustics, waves recorded at the boundary of a strongly scattering medium are sent back into the medium to focus at the original source position. This requires that the medium can be accessed from all sides. We discuss a focusing method for media that can be accessed from one side only.We show how complex focusing functions, emitted from the top surface into the medium, cause independent foci for compressional and shear waves. The focused fields are isotropic and act as independent virtual sources for these wave types inside the medium.We foresee important applications in nondestructive testing of construction materials and seismological monitoring of processes inside the Earth.","","en","journal article","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:049d25c0-1012-4ec4-8df1-9b8bfdaffe66","http://resolver.tudelft.nl/uuid:049d25c0-1012-4ec4-8df1-9b8bfdaffe66","Single-sided Marchenko focusing of compressional and shear waves","Wapenaar, C.P.A.","","2014","In time-reversal acoustics, waves recorded at the boundary of a strongly scattering medium are sent back into the medium to focus at the original source position. This requires that the medium can be accessed from all sides. We discuss a focusing method for media that can be accessed from one side only. We show how complex focusing functions, emitted from the top surface into the medium, cause independent foci for compressional and shear waves. The focused fields are isotropic and act as independent virtual sources for these wave types inside the medium. We foresee important applications in nondestructive testing of construction materials and seismological monitoring of processes inside the Earth.","","en","journal article","American Physical Society","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:a26e5c46-b6a2-4692-96bc-43656b9a2ad4","http://resolver.tudelft.nl/uuid:a26e5c46-b6a2-4692-96bc-43656b9a2ad4","Combining inter-source seismic interferometry and source-receiver interferometry for deep local imaging","Liu, Y.; Arntsen, B.; Wapenaar, C.P.A.; Van der Neut, J.R.","","2014","The virtual source method has been applied successfully to retrieve the impulse response between pairs of receivers in the subsurface. This method is further improved by an updown separation prior to the crosscorrelation to suppress the reflections from the overburden and the free surface. In a reversed situation where the sources are in the subsurface and receivers are on the surface, in principle, one can apply the same logic to retrieve the virtual response between pairs of sources by source-receiver reciprocity, turning the physical borehole sources into virtual receivers. However, since the up-down separation is not applicable on the source side, the simple crosscorrelation of the total fields results in spurious events due to the incomplete receiver coverage around the sources. We show with a numerical example that for this configuration of borehole sources and surface receivers, one can replace such an updown separation at the source side by that of the direct and reflected waves as a first order approximation. This procedure produces the virtual receiver data that is adequate for local imaging below the source depth and is completely independent of the accuracy of the overburden velocity model. We implement this inter-source type of interferometry by multidimensional deconvolution (MDD). Further, if the conventional surface survey data is available, we test the methodology from source-receiver interferometry (SRI) for this reverse configuration with borehole sources to retrieve the virtual receiver data with reflections coming from above, using also only the separation of the direct and reflected waves. By migrating the two sets of virtual receiver data, one can create a local image around the borehole sources in a deep area with better focusing and localization without a sophisticated velocity model.","","en","conference paper","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:36fc8b48-3f70-4187-8993-0072d90ada9f","http://resolver.tudelft.nl/uuid:36fc8b48-3f70-4187-8993-0072d90ada9f","A method to suppress spurious multiples in virtual-source gathers retrieved using seismic interferometry with reflection data","Boullenger, B.; Wapenaar, C.P.A.; Draganov, D.S.","","2014","Seismic interferometry applied to surface reflection data (with source and receivers at the surface) allows to retrieve virtual-source gathers at the position of receivers, where no source was shot. As a result of the crosscorrelation of all primary and multiple reflections, the virtual-source gathers contain retrieved physical reflections as well as non-physical (ghost) reflections also called spurious multiples. We show that a significant part of the ghost reflections can be suppressed by using surface-related multiple elimination on the active data advantageously. The method that we propose consists in retrieving the strong ghost reflections mainly from the crosscorrelation of primaries only and in subtracting this result from the virtual-source gather retrieved from all the data. The resulting new virtual-source gathers provide a better estimate of the reflection response since it is now less polluted by undesired non-physical events that may bring ambiguity in the interpretation. This is better to make a more effective use of the virtual-source gathers, for example for imaging.","correlation; estimation; reflection; reconstruction; adaptive subtraction","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:7b0b9d5d-7895-4d46-9b03-d618bd9734fa","http://resolver.tudelft.nl/uuid:7b0b9d5d-7895-4d46-9b03-d618bd9734fa","Internal multiple suppression by adaptive Marchenko redatuming","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Vasconcelos, I.","","2014","Recently, a novel iterative scheme was proposed to retrieve Green's functions in an unknown medium from its single-sided reflection response and an estimate of the propagation velocity. In Marchenko imaging, these Green's functions are used for seismic imaging with complete wavefields, including internal multiple reflections. In this way, common artifacts from these internal reflections are avoided and illumination of the subsurface can potentially be improved. However, Marchenko imaging requires accurate input data, with correct amplitudes, a deconvolved source signature, without free-surface multiples and source / receiver ghosts. Hence, a significant amount of preprocessing is required, which should be done accurately. To relax these requirements, we propose a scheme to remove artifacts due to internal multiples from inverse-extrapolated wavefields, by adaptively subtracting an estimate of these artifacts that is constructed with the Marchenko equation.","autofocusing; internal multiples","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:097d4a01-a0ae-4741-8bbf-023b10226dfb","http://resolver.tudelft.nl/uuid:097d4a01-a0ae-4741-8bbf-023b10226dfb","On the focusing conditions in time-reversed acoustics, seismic interferometry, and Marchenko imaging","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Vasconcelos, I.; Van Manen, D.J.; Ravasi, M.","","2014","Despite the close links between the fields of time-reversed acoustics, seismic interferometry and Marchenko imaging, a number of subtle differences exist. This paper reviews the various focusing conditions of these methods, the causality/acausality aspects of the corresponding focusing wavefields, and the requirements with respect to omnidirectional/single-sided acquisition.","imaging; internal multiples","en","conference paper","SEG","","","","","","","","Applied Sciences","ImPhys/Imaging Physics","","","","" "uuid:a3762abc-0fae-4b0b-bea6-aa571f2db3e2","http://resolver.tudelft.nl/uuid:a3762abc-0fae-4b0b-bea6-aa571f2db3e2","Autofocusing imaging: Imaging with primaries, internal multiples and free-surface multiples","Singh, S.; Snieder, R.; Behura, J.; van der Neut, J.R.; Wapenaar, C.P.A.; Slob, E.C.","","2014","Recent work on autofocusing with the Marchenko equation has shown how the Green's function for a virtual source in the subsurface can be obtained from reflection data. The response to the virtual source is the Green's function from the location of the virtual source to the surface. The Green's function is retrieved using only the reflection response of the medium and an estimate of the first arrival at the surface from the virtual source. Current techniques, however, only include primaries and internal multiples. Therefore, all surface-related multiples must be removed from the reflection response prior to Green's function retrieval. Here, we extend the Marchenko equation to retrieve the Green's function that includes primaries, internal multiples, and free-surface multiples. In other words, we retrieve the Green's function in the presence of a free surface. We use the associated Green's function for imaging the subsurface. The information needed for the retrieval are the reflection response at the surface and an estimate of the first arrival at the surface from the virtual source. The reflection response, in this case, includes the free-surface multiples; this makes it possible to include these multiples in the imaging operator and it obviates the need for surface-related multiple elimination.","imaging; multiples; scattering; autofocusing; internal multiples","en","conference paper","SEG","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:0717bd46-5ec4-4535-8dda-fd74cfd874ee","http://resolver.tudelft.nl/uuid:0717bd46-5ec4-4535-8dda-fd74cfd874ee","Infrasonic interferometry applied to microbaroms observed at the Large Aperture Infrasound Array in the Netherlands","Fricke, J.T.; Evers, L.G.; Smets, P.S.M.; Wapenaar, C.P.A.; Simons, D.G.","","2014","We present the results of infrasonic interferometry applied to microbaroms, obtained from ambient noise. For this purpose the “Large Aperture Infrasound Array” (LAIA) was used, which has been installed in the Netherlands. Preprocessing appeared to be an essential step in enhancing the microbarom signals from ambient noise that strongly influences the results of the interferometry. Both the state of the atmosphere and the noise characteristics are taken into account to assess the strength of the cross correlation. The delay time of the microbaroms between two stations is determined through cross correlating the recordings. By calculating the cross correlations between all 55 station pairs of LAIA, we are able to find the delay time of microbaroms up to a interstation distance of 40.6 km. Using the strength of the cross correlations, we are able to show that the coherence of the microbaroms along the direction of arrival is higher than orthogonal to it. A comparison of the atmospheric state, with a cross correlation, over a period of 10 days, reveals that the infrasound propagation over the array is correlated with the tropospheric temperature and wind. Based on the cross correlations between the three closest stations, we are able to passively estimate the effective sound speed and the wind speed as a function of time.","infrasonic interferometry; microbaroms; troposphere","en","journal article","American Geophysical Union","","","","","","","2015-02-19","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:84266f03-b9e6-4fe6-9e74-a727c641d9f5","http://resolver.tudelft.nl/uuid:84266f03-b9e6-4fe6-9e74-a727c641d9f5","Marchenko imaging","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","","","en","lecture notes","","","","","","","","","","","","","","" "uuid:ca8cdd02-139a-423c-94f2-540330603ccf","http://resolver.tudelft.nl/uuid:ca8cdd02-139a-423c-94f2-540330603ccf","Shear wave seismic interferometry for lithospheric imaging: Application to southern Mexico","Frank, J.G.; Ruigrok, E.N.; Wapenaar, C.P.A.","","2014","Seismic interferometry allows for the creation of new seismic traces by cross correlating existing ones. With sufficient sampling of remote-source positions, it is possible to create a virtual source record by transforming a receiver location into a virtual source. The imaging technique developed here directly retrieves reflectivity information from the subsurface. Other techniques, namely receiver-function and tomography, rely on mode-converted energy and perturbations in a velocity field, respectively, to make inferences regarding structure. We select shear phases as an imaging source because of their lower propagation velocity, sensitivity to melt, and ability to treat vertical shear and horizontal shear wavefields independently. Teleseismic shear phases approximate a plane wave due to the extent of wavefront spread compared to a finite receiver array located on the free surface. The teleseismic shear phase transmission responses are used as input to the seismic interferometry technique. We create virtual shear source records by converting each receiver in the array into a virtual source. By cross correlating the received signals, the complex source character of distant earthquakes is imprinted on the virtual source records as the average autocorrelation of individual source-time functions. We demonstrate a technique that largely removes this imprint by filtering in the common-offset domain. A field data set was selected from the Meso-America Subduction Experiment. Despite the suboptimal remote-source sampling, an image of the lithosphere was produced that confirms features of the subduction zone that were previously found with the receiver-function technique.","lithosphere; seismic interferometry; imaging; shear waves","en","journal article","American Geophysical Union","","","","","","","2015-01-17","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6b6317a1-9e4f-4d6b-bb2c-9e2d803e6625","http://resolver.tudelft.nl/uuid:6b6317a1-9e4f-4d6b-bb2c-9e2d803e6625","Autofocus imaging: Image reconstruction based on inverse scattering theory","Behura, J.; Wapenaar, C.P.A.; Snieder, R.","","2014","Conventional imaging algorithms assume single scattering and therefore cannot image multiply scattered waves correctly. The multiply scattered events in the data are imaged at incorrect locations resulting in spurious subsurface structures and erroneous interpretation. This drawback of current migration/imaging algorithms is especially problematic for regions where illumination is poor (e.g., subsalt), in which the spurious events can mask true structure. Here we discuss an imaging technique that not only images primaries but also internal multiples accurately. Using only surface reflection data and direct-arrivals, we generate the up- and down-going wavefields at every image point in the subsurface. An imaging condition is applied to these up- and downgoing wavefields directly to generate the image. Because the above algorithm is based on inverse-scattering theory, the reconstructed wavefields are accurate and contain multiply scattered energy in addition to the primary event. As corroborated by our synthetic examples, imaging of these multiply scattered energy helps eliminate spurious reflectors in the image. Other advantages of this imaging algorithm over existing imaging algorithms include more accurate amplitudes, target-oriented imaging, and a highly parallelizable algorithm.","","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:640f712d-dd99-4a5c-a65f-6e2fdcc50ba9","http://resolver.tudelft.nl/uuid:640f712d-dd99-4a5c-a65f-6e2fdcc50ba9","Wavefield decomposition of field data, using a shallow horizontal downhole sensor array and a free-surface constraint","Grobbe, N.; van der Neut, J.R.; Almagro Vidal, C.; Drijkoningen, G.G.; Wapenaar, C.P.A.","","2014","Separation of recorded wavefields into downgoing and upgoing constituents is a technique that is used in many geophysical methods. The conventional, multi-component (MC) wavefield decomposition scheme makes use of different recorded wavefield components. In recent years, land acquisition designs have emerged that make use of shallow horizontal downhole sensor arrays. Inspired by marine acquisitiondesigns that make use of recordings at multiple depth levels for wavefield decomposition, we have recently developed a multi-depth level (MDL) wavefield decomposition scheme for land acquisition. Exploiting the underlying theory of this scheme, we now consider conventional, multi-component (MC) decomposition as an inverse problem, which we try to constrain in a better way. We have overdetermined the inverse problem by adding an MDL equation that exploits the Dirichlet free-surface boundary condition. To investigate the successfulness of this approach, we have applied both MC and combined MC-MDL decomposition to a real land dataset acquired in Annerveen, the Netherlands. Comparison of the results of overdetermined MC-MDL decomposition with the results of MC wavefield decomposition, clearly shows improvements in the obtained one-way wavefields, especially for the downgoing fields.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:50734e45-3a08-4986-b8ba-5c711daa76bf","http://resolver.tudelft.nl/uuid:50734e45-3a08-4986-b8ba-5c711daa76bf","Locating cavities using ghost scattered waves in a scale-model experiment","Harmankaya, U.; Kaslilar, A.; Verstraeten, B.; Creten, S.; Glorieux, C.; Wapenaar, C.P.A.; Draganov, D.S.","","2014","The investigation and detection of near-surface structures (cavities, caves, tunnels, mineshafts, buried objects, archeological ruins, water reservoir, etc.) is important to mitigate geo- and environmental hazards. We use a method inspired by seismic interferometry to estimate the location of a cavity in a scaled ultrasonic experiment, representative for geophysical field problems. We use only one source at the surface and retrieve ghost scattered waves by evaluating the correlation of scattered waves at different receiver locations. As an exploitation of the ghost arrival information, the ghost travel times are determined and combined to estimate the location of a cavity with good accuracy.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f9b8ba0d-c83d-4b1c-9450-ca1cc2ae8bcb","http://resolver.tudelft.nl/uuid:f9b8ba0d-c83d-4b1c-9450-ca1cc2ae8bcb","Turning subsurface noise sources into virtual receivers by multi-dimensional deconvolution","Liu, Y.; Wapenaar, C.P.A.; Arntsen, B.","","2014","The retrieval of the Green's functions between receiver pairs by multi-dimensional deconvolution can be extended to extract the impulse response between source pairs through source-receiver reciprocity. However in general, the procedure requires the separation of the outgoing and incoming wavefields at the sources, which reduces to the separation of the direct waves and the reflected waves in the absence of free-surface and inter-layer multiples. We show that in theory, for non-transient noise sources where the separation may not be obvious in the data domain, the separation can be achieved by time-windowing in an intermediate crosscorrelation step, which can be readily included in the MDD scheme. We illustrate the method with a synthetic model.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8c2fce50-b63b-4eac-99ad-70265c9f275e","http://resolver.tudelft.nl/uuid:8c2fce50-b63b-4eac-99ad-70265c9f275e","An interferometric interpretation of Marchenko redatuming","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2014","Recently, an iterative scheme was introduced to retrieve up- and downgoing Green’s functions at an arbitrary location F in the subsurface. The scheme uses the reflection data as acquired at the surface as input, together with an estimate of the direct arrival from the surface to location F, which is referred to as the initial focusing function. We interpret the overall action of the scheme as the successive actions of various linear filters, acting on the initial focusing function. These filters involve multidimensional crosscorrelations with the reflection response, time reversals and truncations in time. Inspired by literature on seismic interferometry, we interpret multidimensional crosscorrelation in terms of the subtraction of traveltimes along stationary raypaths. The scheme has been designed for layered media with smooth interfaces. Our interferometric interpretation reveals some of the scheme’s limitations when it is applied to more complex configurations. It can be concluded that (downgoing or upgoing) internal multiples that arrive at F with a particular angle can be retrieved only if the initial focusing function (i.e., the direct wave) has visited F with this angle. Consequently, shadow zones that cannot be imaged with primary reflections can theoretically also not be imaged with internal multiples, when the current iterative scheme is used for their retrieval. Finally, we observe that the current scheme does not yet optimally perform in media with point scatterers, since an underlying assumption (generally referred to as the ansatz) is not perfectly obeyed in this case. It is envisioned that this can be improved if truncations in time that are implemented after each iteration are replaced by more advanced filtering methods.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:e1657f41-faa4-4d63-a407-a34dc49cdbd0","http://resolver.tudelft.nl/uuid:e1657f41-faa4-4d63-a407-a34dc49cdbd0","Marchenko imaging below an overburden with random scatterers","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Vasconcelos, I.; Slob, E.C.","","2014","Marchenko imaging is a new way to deal with internal multiple scattering in migration. It has been designed for layered media with smooth interfaces. Here we analyze the performance of the Marchenko scheme for a medium with many point scatterers. Although the conditions for Marchenko imaging are violated, we observe from a numerical experiment that the signal-to-noise ratio of the obtained image is significantly higher than with standard imaging.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:6954f84f-20e2-4a93-919b-41a26298ae02","http://resolver.tudelft.nl/uuid:6954f84f-20e2-4a93-919b-41a26298ae02","Overview of marine controlled-source electromagnetic interferometry by multidimensional deconvolution","Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.","","2014","Interferometry by multidimensional deconvolution for marine Controlled-Source Electromagnetics can suppress the direct field and the airwave in order to increase the detectability of the reservoir. For monitoring, interferometry by multidimensional deconvolution can increase the source repeatability. We give an overview over the method and discuss a possible path of research for the future.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:4dab07ba-394d-456a-9bda-2632a45e5ed4","http://resolver.tudelft.nl/uuid:4dab07ba-394d-456a-9bda-2632a45e5ed4","On the Marchenko equation for multicomponent single-sided reflection data","Wapenaar, C.P.A.; Slob, E.C.","","2014","Recent work on the Marchenko equation has shown that the scalar 3-D Green’s function for a virtual source in the subsurface can be retrieved from the single-sided reflection response at the surface and an estimate of the direct arrival. Here, we discuss the first steps towards extending this result to multicomponent data. After introducing a unified multicomponent 3-D Green’s function representation, we analyse its 1-D version for elastodynamic waves in more detail. It follows that the main additional requirement is that the multicomponent direct arrival, needed to initiate the iterative solution of the Marchenko equation, includes the forward-scattered field. Under this and other conditions, the multicomponent Green’s function can be retrieved from single-sided reflection data, and this is demonstrated with a 1-D numerical example.","interferometry; controlled source seismology; wave scattering and diffraction","en","journal article","Oxford University Press","","","","","","","","Applied Sciences","ImPhys/Imaging Physics","","","","" "uuid:8e8655c9-4b23-4f9e-9339-37c372be931b","http://resolver.tudelft.nl/uuid:8e8655c9-4b23-4f9e-9339-37c372be931b","An interferometric interpretation of Marchenko redatuming","Van der Neut, J.R.; Vasconcelos, I.; Wapenaar, C.P.A.","","2014","","","en","lecture notes","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:1f984a23-467a-499c-90a1-68e98b728ad8","http://resolver.tudelft.nl/uuid:1f984a23-467a-499c-90a1-68e98b728ad8","Data-driven wavefield focusing and imaging with multidimensional deconvolution: Numerical examples for reflection data with internal multiples","Broggini, F.; Snieder, R.; Wapenaar, C.P.A.","","2014","Standard imaging techniques rely on the single scattering assumption. This requires that the recorded data do not include internal multiples, i.e., waves that have bounced multiple times between reflectors before reaching the receivers at the acquisition surface. When multiple reflections are present in the data, standard imaging algorithms incorrectly image them as ghost reflectors. These artifacts can mislead interpreters in locating potential hydrocarbon reservoirs. Recently, we introduced a new approach for retrieving the Green’s function recorded at the acquisition surface due to a virtual source located at depth. We refer to this approach as data-driven wavefield focusing. Additionally, after applying source-receiver reciprocity, this approach allowed us to decompose the Green’s function at a virtual receiver at depth in its downgoing and upgoing components. These wavefields were then used to create a ghost-free image of the medium with either crosscorrelation or multidimensional deconvolution, presenting an advantage over standard prestack migration. We tested the robustness of our approach when an erroneous background velocity model is used to estimate the first-arriving waves, which are a required input for the data-driven wavefield focusing process. We tested the new method with a numerical example based on a modification of the Amoco model.","multiples; migration; reciprocity; crosscorrelation","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:61ad5e42-e10d-470c-a500-382090e1bff5","http://resolver.tudelft.nl/uuid:61ad5e42-e10d-470c-a500-382090e1bff5","Marchenko imaging","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","Traditionally, the Marchenko equation forms a basis for 1D inverse scattering problems. A 3D extension of the Marchenko equation enables the retrieval of the Green’s response to a virtual source in the subsurface from reflection measurements at the earth’s surface. This constitutes an important step beyond seismic interferometry. Whereas seismic interferometry requires a receiver at the position of the virtual source, for the Marchenko scheme it suffices to have sources and receivers at the surface only. The underlying assumptions are that the medium is lossless and that an estimate of the direct arrivals of the Green’s function is available. The Green’s function retrieved with the 3D Marchenko scheme contains accurate internal multiples of the inhomogeneous subsurface. Using source-receiver reciprocity, the retrieved Green’s function can be interpreted as the response to sources at the surface, observed by a virtual receiver in the subsurface. By decomposing the 3D Marchenko equation, the response at the virtual receiver can be decomposed into a downgoing field and an upgoing field. By deconvolving the retrieved upgoing field with the downgoing field, a reflection response is obtained, with virtual sources and virtual receivers in the subsurface. This redatumed reflection response is free of spurious events related to internal multiples in the overburden. The redatumed reflection response forms the basis for obtaining an image of a target zone. An important feature is that spurious reflections in the target zone are suppressed, without the need to resolve first the reflection properties of the overburden.","multiples; migration; reciprocity","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c9d6af44-5c03-4d03-b5b7-a9895cc37864","http://resolver.tudelft.nl/uuid:c9d6af44-5c03-4d03-b5b7-a9895cc37864","Green's function retrieval from reflection data, in absence of a receiver at the virtual source position","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Slob, E.C.; Snieder, R.","","2014","The methodology of Green’s function retrieval by cross-correlation has led to many interesting applications for passive and controlled-source acoustic measurements. In all applications, a virtual source is created at the position of a receiver. Here a method is discussed for Green’s function retrieval from controlled-source reflection data, which circumvents the requirement of having an actual receiver at the position of the virtual source. The method requires, apart from the reflection data, an estimate of the direct arrival of the Green’s function. A single-sided three-dimensional (3D) Marchenko equation underlies the method. This equation relates the reflection response, measured at one side of the medium, to the scattering coda of a so-called focusing function. By iteratively solving the 3D Marchenko equation, this scattering coda is retrieved from the reflection response. Once the scattering coda has been resolved, the Green’s function (including all multiple scattering) can be constructed from the reflection response and the focusing function. The proposed methodology has interesting applications in acoustic imaging, properly accounting for internal multiple scattering.","","en","journal article","Acoustical Society of America","","","","","","","2014-11-01","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:493d1089-c862-4cea-96b2-e4345cb41fe5","http://resolver.tudelft.nl/uuid:493d1089-c862-4cea-96b2-e4345cb41fe5","Inter-source seismic interferometry by multidimensional deconvolution (MDD) for borehole sources","Liu, Y.; Wapenaar, C.P.A.; Romdhane, A.","","2014","Seismic interferometry (SI) is usually implemented by crosscorrelation (CC) to retrieve the impulse response between pairs of receiver positions. An alternative approach by multidimensional deconvolution (MDD) has been developed and shown in various studies the potential to suppress artifacts due to irregular source distribution and intrinsic loss. Following previous theories on SI by MDD, we extend it to retrieve the impulse response between pairs of source positions by invoking source and receiver reciprocity. We verify the theory using a simple two-layered model and show that the retrieved response by MDD is more accurate than that by CC, and furthermore, it is free of free-surface multiples. We discuss the necessary pre-processing required for this method. This inter-source SI approach creates a virtual acquisition geometry with both borehole sources and receivers without the need to deploy receivers in the borehole, which might be of interest to applications such as seismic while drilling (SWD).","","en","conference paper","Chinese Petroleum Society / Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:43c97470-96cc-474a-a1ea-f61685040f49","http://resolver.tudelft.nl/uuid:43c97470-96cc-474a-a1ea-f61685040f49","Data-driven inversion of GPR surface reflection data for lossless layered media","Slob, E.C.; Wapenaar, C.P.A.","","2014","Two wavefields can be retrieved from the measured reflection response at the surface. One is the Green’s function at a chosen virtual receiver depth level in a layered model generated by a source at the surface. The other wavefield consists of the upgoing and downgoing parts of a wavefield that focuses at the virtual receiver depth level. From the upgoing part of the focusing wavefield an image can be computed at one-way vertical travel time and with correct amplitudes of the local reflection coefficients as a function of incidence angle. These reflection coefficient values can be used to invert for electric permittivity and magnetic permeability. From these values and the known image times the layer thickness values can be obtained for each layer. This method renders the full waveform inversion problem for horizontally layered media a linear problem.","antenna; propagation; measurement","en","conference paper","European Association on Antennas and Propagation","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:33dea679-41a9-45b7-953f-987cdd26babd","http://resolver.tudelft.nl/uuid:33dea679-41a9-45b7-953f-987cdd26babd","Seismic reflector imaging using internal multiples with Marchenko-type equations","Slob, E.C.; Wapenaar, C.P.A.; Broggini, F.; Snieder, R.","","2014","We present an imaging method that creates a map of reflection coefficients in correct one-way time with no contamination from internal multiples using purely a filtering approach. The filter is computed from the measured reflection response and does not require a background model. We demonstrate that the filter is a focusing wavefield that focuses inside a layered medium and removes all internal multiples between the surface and the focus depth. The reflection response and the focusing wavefield can then be used for retrieving virtual vertical seismic profile data, thereby redatuming the source to the focus depth. Deconvolving the upgoing by the downgoing vertical seismic profile data redatums the receiver to the focus depth and gives the desired image. We then show that, for oblique angles of incidence in horizontally layered media, the image of the same quality as for 1D waves can be constructed. This step can be followed by a linear operation to determine velocity and density as a function of depth. Numerical simulations show the method can handle finite frequency bandwidth data and the effect of tunneling through thin layers.","imaging; reverse time migration; velocity analysis","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:8e10d71b-962d-47c1-8a88-a00a02331765","http://resolver.tudelft.nl/uuid:8e10d71b-962d-47c1-8a88-a00a02331765","Marchenko redatuming below a complex overburden","Van der Neut, J.R.; Wapenaar, C.P.A.; Thorbecke, J.W.; Vasconcelos, I.","","2014","Complex overburdens can severely distort transmitted wavefields, posing serious challenges for seismic imaging. In Marchenko redatuming, we use an iterative scheme to estimate so-called focusing functions, which can be used to redatum seismic wavefields to a specified level below the major complexities in the subsurface. Unlike in conventional redatuming methods, internal scattering in the overburden is accounted for by this methodology. Through Marchenko redatuming, internal multiple reflections are effectively utilized and common artefacts that are caused by these multiples are suppressed. The redatumed data can be interpreted as if it were acquired at the redatuming level and as if the medium above this level were non-reflecting. We provide an interpretation of the iterative scheme that is used for Marchenko redatuming and we evaluate its performance in a medium with a strongly heterogeneous overburden.","","en","conference paper","KAUST","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f1750374-9a25-4f81-a5d5-e99279aec31e","http://resolver.tudelft.nl/uuid:f1750374-9a25-4f81-a5d5-e99279aec31e","Data-driven Green's function retrieval and application to imaging with multidimensional deconvolution","Broggini, F.; Wapenaar, C.P.A.; Van der Neut, J.R.; Snieder, R.","","2014","An iterative method is presented that allows one to retrieve the Green's function originating from a virtual source located inside a medium using reflection data measured only at the acquisition surface. In addition to the reflection response, an estimate of the travel times corresponding to the direct arrivals is required. However, no detailed information about the heterogeneities in the medium is needed. The iterative scheme generalizes the Marchenko equation for inverse scattering to the seismic reflection problem. To give insight in the mechanism of the iterative method, its steps for a simple layered medium are analyzed using physical arguments based on the stationary phase method. The retrieved Green's wavefield is shown to correctly contain the multiples due to the inhomogeneities present in the medium. Additionally, a variant of the iterative scheme enables decomposition of the retrieved wavefield into its downgoing and upgoing components. These wavefields then enable creation of a ghost-free image of the medium with either cross correlation or multidimensional deconvolution, presenting an advantage over standard prestack migration.","autofocusing; Marchenko; scattering; interferometry; Green's function","en","journal article","American Geophysical Union","","","","","","","2014-07-17","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:192ce582-153c-4bd9-961a-b0a864b6ce22","http://resolver.tudelft.nl/uuid:192ce582-153c-4bd9-961a-b0a864b6ce22","Estimating the location of a tunnel using correlation and inversion of Rayleigh wave scattering","Kasililar, A.; Harmankaya, U.; Wapenaar, C.P.A.; Draganov, D.S.","","2013","The investigation of near-surface scatterers, such as cavities, tunnels, abandoned mine shafts, and buried objects, is important to mitigate geohazards and environmental hazards. By inversion of travel times of cross-correlated scattered waves, due to the incident Rayleigh waves, we estimate the location of a near-surface tunnel from seismic field data. The cross correlation eliminates the travel path between a source and a scatterer, thus eliminating the need to know the position of the source, making the estimation of the scatterers' locations dependent only on properties between the receivers and the scatterer. First time using a numerically verified method on seismic field data, we show the potential of the method for estimating the location of a buried scatterer.","locating scatterers; ghost-scattered waves; seismic interferometry; Rayleigh waves; inversion; active source","en","journal article","American Geophysical Union","","","","","","","2014-06-10","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c7f6428c-0846-4d25-84ea-4090725836d3","http://resolver.tudelft.nl/uuid:c7f6428c-0846-4d25-84ea-4090725836d3","Estimating the location of a tunnel using correlation and inversion of Rayleigh wave scattering","Kaslilar, A.; Harmankaya, U.; Wapenaar, C.P.A.; Draganov, D.S.","","2013","The investigation of near-surface scatterers, such as cavities, tunnels, abandoned mine shafts, and buried objects, is important to mitigate geohazards and environmental hazards. By inversion of travel times of cross-correlated scattered waves, due to the incident Rayleigh waves, we estimate the location of a near-surface tunnel from seismic field data. The cross correlation eliminates the travel path between a source and a scatterer, thus eliminating the need to know the position of the source, making the estimation of the scatterers’ locations dependent only on properties between the receivers and the scatterer. First time using a numerically verified method on seismic field data, we show the potential of the method for estimating the location of a buried scatterer.","","en","journal article","American Geophysical Union","","","","","","","2014-06-10","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:ed7d7c16-4570-4c65-a898-aeda07de6b8c","http://resolver.tudelft.nl/uuid:ed7d7c16-4570-4c65-a898-aeda07de6b8c","Surface wave retrieval in layered media using seismic interferometry by multidimensional deconvolution","Van Dalen, K.N.; Wapenaar, C.P.A.; Halliday, D.F.","","2013","Virtual-source surface wave responses can be retrieved using the crosscorrelation (CC) of wavefields observed at two receivers. Higher mode surface waves cannot be properly retrieved when there is a lack of subsurface sources that excite these wavefields, as is often the case. In this paper, we present a multidimensional-deconvolution (MDD) scheme that is based on an approximate convolution theorem. The scheme introduces an additional processing step in which the CC result is deconvolved by a so-called point-spread tensor. The involved point-spread functions capture the imprint of the lack of subsurface sources and possible anelastic effects, and quantify the associated spatial and temporal smearing of the virtualsource components that leads to the poor surfacewave retrieval. The functions can be calculated from the same wavefields as used in the CC method. For a 2-D example that is representative of the envisaged applications, we show that the deconvolution partially corrects for the smearing. The retrieved virtual-source response only has some amplitude error in the ideal situation of having the depth of the required vertical array equal to the depth penetration of the surface waves. The error is due to ignored cross-mode terms in the approximate convolution theorem. Shorter arrays are also possible. In the limit case of only a single surface receiver, the retrieved virtual-source response is still more accurate than the CC result. The MDD scheme is valid for horizontally layered media that are laterally invariant, and includes exclusively multicomponent point-force responses (rather than their spatial derivatives) and multicomponent observations. The improved retrieval of multimode surface waves can facilitate dispersion analyses in shallow-subsurface inversion problems and monitoring, and surface wave removal algorithms.","interferometry; surface waves and free oscillations; interface waves","en","journal article","Oxford University Press","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","","" "uuid:5ac5be23-4fc0-4b2d-9ec5-1b799e8944f1","http://resolver.tudelft.nl/uuid:5ac5be23-4fc0-4b2d-9ec5-1b799e8944f1","Green's function retrieval with Marchenko equations: A sensitivity analysis","Thorbecke, J.W.; Van der Neut, J.R.; Wapenaar, C.P.A.","","2013","Recent research showed that the Marchenko equation can be used to construct the Green’s function for a virtual source position in the subsurface. The method requires the reflection response at the surface and an estimate of the direct arrival of the wavefield, traveling from the virtual source location to the acquisition surface. In this paper, we investigate the sensitivity of this method. We demonstrate its robustness with respect to significant amplitude and phase errors in the direct arrival. The erroneous operators introduce low amplitude artefacts. The main reflections and internal multiples are still presents and disturbing ghost events are not introduced. In case the reflection data is modeled in a medium with losses, ghost events seem to be visible in the upgoing wavefield, but not in the downgoing wavefield.","imaging; migration; multiples; decomposition; reconstruction","en","conference paper","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:1f1bee17-2f4e-4b7c-916d-c951f25339f6","http://resolver.tudelft.nl/uuid:1f1bee17-2f4e-4b7c-916d-c951f25339f6","Coupled Marchenko equations for electromagnetic Green’s function retrieval and imaging","Slob, E.C.; Wapenaar, C.P.A.","","2013","Recently a new theory has been developed to retrieve a wavefield generated by a source on the surface and recorded at a point in the subsurface without the need for a receiver at that subsurface location. The scheme is presented for three-dimensional wavefields. It decomposes the electromagnetic field in up- and downgoing electric fields and in TE- and TM-modes. Each mode can be treated separately to construct the Green’s function. We derive two coupled Marchenko equations from which the up- and downgoing Green’s functions can be obtained. These two directional Green’s functions have applications in true-amplitude subsurface imaging without effects from internal multiple reflections.","GPR; imaging; reconstruction","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:586e95fb-bfba-4ca5-9077-99de795a6415","http://resolver.tudelft.nl/uuid:586e95fb-bfba-4ca5-9077-99de795a6415","Interferometric reservoir monitoring with a single passive source","Almagro Vidal, C.; Van der Neut, J.; Wapenaar, C.P.A.","","2013","Changes in the subsurface can be imaged by subtracting seismic reflection data at two different states, one serving as the initial survey or base, and the second as the monitor survey. Conventionally, the reflection data are acquired by placing active seismic sources at the acquisition surface. Alternatively, these data can be acquired from passive sources in the subsurface, using seismic interferometry. Unfortunately, the reflection responses as retrieved by seismic interferometry inherit an imprint of the passive source distribution. Therefore, monitoring with seismic interferometry requires high passive source repeatability, which is often not achievable in practice. We propose an alternative, by using active seismic data for the base survey and a single passive source for the monitor survey. By constraining the radiation pattern of the (active) base survey according to the characteristics of the (passive) monitor survey, we succeed to extract time-lapse response in the image domain. The proposed method is illustrated with numerically modeled data.","earthquake; imaging; monitoring; passive; seismic","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:020d09ea-f839-4a5a-8e7f-2a18f151e92e","http://resolver.tudelft.nl/uuid:020d09ea-f839-4a5a-8e7f-2a18f151e92e","Interferometric redatuming of autofocused primaries and internal multiples","Van der Neut, J.; Slob, E.C.; Wapenaar, C.P.A.; Throbecke, J.W.; Snieder, R.; Broggini, F.","","2013","Recently, an iterative scheme has been introduced to retrieve the down- and upgoing Green's functions at an arbitrary level ?F inside an acoustic medium as if there were a source at the surface. This scheme requires as input the reflection response acquired at the surface and the direct arrival of the transmission response from the surface to level ?F. The source locations of these Green's functions can be effectively redatumed to level ?F by interferometric redatuming, which requires solving a multidimensional deconvolution problem, essentially being a Fredholm integral equation of the first kind. We show how this problem can be simplified by rewriting it as a Fredholm integral equation of the second kind that can be expanded as a Neumann series. Redatumed data can be used for multiplefree true-amplitude imaging at or in the vicinity of ?F. For imaging the closest reflector to ?F only, the Neumann series can be truncated at the first term without losing accuracy.","datuming; illumination; multiples; seismic","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:09ea03c7-f34c-4407-804d-a37531037f2a","http://resolver.tudelft.nl/uuid:09ea03c7-f34c-4407-804d-a37531037f2a","Data-driven Green's function retrieval and imaging with multidimensional deconvolution: Numerical examples for reflection data with internal multiples","Broggini, F.; Snieder, R.; Wapenaar, C.P.A.","","2013","Standard imaging techniques rely on the single scattering assumption. This requires that the recorded data do not include internal multiples, i.e. waves bouncing multiple times between layers before reaching the receivers at the acquisition surface. When multiple reflections are present in the data, standard imaging algorithms incorrectly image them as ghost reflectors. These artifacts can mislead the interpreters in locating potential hydrocarbon reservoirs. Recently, we introduced a new approach for retrieving the Greens function recorded at the acquisition surface due to a virtual source located at depth. Additionally, our approach allows us to decompose the Green's function in its downgoing and upgoing components. These wave fields are then used to create a ghostfree image of the medium with either crosscorrelation or multidimensional deconvolution, presenting an advantage over standard prestack migration. We illustrate the new method with a numerical example based on a modification of the Amoco model.","acoustic; migration; multiples","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:337306c1-4ad9-49a0-90de-bed90539994a","http://resolver.tudelft.nl/uuid:337306c1-4ad9-49a0-90de-bed90539994a","Three-dimensional Marchenko equation for Green's function retrieval “beyond seismic interferometry”","Wapenaar, C.P.A.; Slob, E.C.; Van der Neut, J.; Thorbecke, J.W.; Broggini, F.; Snieder, R.","","2013","In recent work we showed with heuristic arguments that the Green's response to a virtual source in the subsurface can be obtained from reflection data at the surface. This method is called “Green's function retrieval beyond seismic interferometry”, because, unlike in seismic interferometry, no receiver is needed at the position of the virtual source. Here we present a formal derivation of Green's function retrieval beyond seismic interferometry, based on a 3-D extension of the Marchenko equation. We illustrate the theory with a numerical example and indicate the potential applications in seismic imaging and AVA analysis.","multiples; reciprocity; wave equation; reverse-time","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:3f9194dc-95ba-4799-8feb-2edfc3e8d512","http://resolver.tudelft.nl/uuid:3f9194dc-95ba-4799-8feb-2edfc3e8d512","Infrasonic interferometry of stratospherically refracted microbaroms: A numerical study","Fricke, J.T.; El Allouche, N.; Simons, D.G.; Ruigrok, E.N.; Wapenaar, C.P.A.; Evers, L.G.","","2013","The atmospheric wind and temperature can be estimated through the traveltimes of infrasound between pairs of receivers. The traveltimes can be obtained by infrasonic interferometry. In this study, the theory of infrasonic interferometry is verified and applied to modeled stratospherically refracted waves. Synthetic barograms are generated using a raytracing model and taking into account atmospheric attenuation, geometrical spreading, and phase shifts due to caustics. Two types of source wavelets are implemented for the experiments: blast waves and microbaroms. In both numerical experiments, the traveltimes between the receivers are accurately retrieved by applying interferometry to the synthetic barograms. It is shown that microbaroms can be used in practice to obtain the traveltimes of infrasound through the stratosphere, which forms the basis for retrieving the wind and temperature profiles.","","en","journal article","Acoustical Society of America","","","","","","","2014-04-01","Aerospace Engineering","Control & Operations","","","","" "uuid:9034f459-65bf-45fe-9ea2-36e499de1803","http://resolver.tudelft.nl/uuid:9034f459-65bf-45fe-9ea2-36e499de1803","Seismic exploration?scale velocities and structure from ambient seismic noise (>1?Hz)","Draganov, D.S.; Campman, X.; Thorbecke, J.W.; Verdel, A.; Wapenaar, C.P.A.","","2013","The successful surface waves retrieval in solid?Earth seismology using long?time correlations and subsequent tomographic images of the crust have sparked interest in extraction of subsurface information from noise in the exploration seismology. Subsurface information in exploration seismology is usually derived from body?wave reflections >?1?Hz, which is challenging for utilization of ambient noise. We use 11?h of noise recorded in the Sirte basin, Libya. First, we study the characteristics of the noise. We show that the bulk of the noise is composed of surface waves at frequencies below 6?Hz. Some noise panels contain nearly vertically traveling events. We further characterize these events using a beamforming algorithm. From the beamforming, we conclude that these events represent body?wave arrivals with a fairly rich azimuthal distribution. Having body?wave arrivals in the noise is a prerequisite for body?wave reflections retrieval. We crosscorrelate and sum the recorded ambient?noise panels to retrieve common?source gathers, following two approaches—using all the noise and using only noise panels containing body?wave arrivals likely to contribute to the reflections retrieval. Comparing the retrieved gathers with active seismic data, we show that the two?way traveltimes at short offsets of several retrieved events coincide with those of reflections in the active data and thus correspond to apexes of reflections. We then compare retrieved stacked sections of the subsurface from both approaches with the active?data stacked section and show that the reflectors are consistent along a line. The results from the second approach exhibit the reflectors better.","seismic noise; crosscorrelation; imaging; body waves; reflections","en","journal article","American Geophysical Union","","","","","","","2014-02-28","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f9f4a019-9537-4040-b1d5-4c33a2093c18","http://resolver.tudelft.nl/uuid:f9f4a019-9537-4040-b1d5-4c33a2093c18","Data-driven green's function retrieval from reflection data: Theory and example","Wapenaar, C.P.A.; Slob, E.C.; Broggini, F.; Snieder, R.; Thorbecke, J.W.; Van der Neut, J.R.","","2013","Recently we introduced a new approach for retrieving the Green's response to a virtual source in the subsurface from reflection data at the surface. Unlike in seismic interferometry, no receiver is needed at the position of the virtual source. Here we present the theory behind this new method. First we introduce the Green's function G and a so-called fundamental solution F of an inhomogeneous medium. Next we derive a relation between G and F, using reciprocity theorems. This relation is used as the basis for deriving a 3D single-sided Marchenko equation. We show that this equation is solved by a 3D autofocusing scheme and that the Green's function is obtained by combining the focusing wave field and its response in a specific way. We illustrate the method with a numerical example.","","en","conference paper","Eage","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:b7664c48-8b2a-4ca7-9cc1-2fab32183a87","http://resolver.tudelft.nl/uuid:b7664c48-8b2a-4ca7-9cc1-2fab32183a87","Turning One-sided Illumination into Two-sided Illumination by Target-enclosing Interferometric Redatuming","Van der Neut, J.R.; Almagro Vidal, C.; Grobbe, N.; Wapenaar, C.P.A.","","2013","We present a novel method to transform seismic data with sources at the surface and receivers above and below a selected target zone in the subsurface into virtual data with sources and receivers located at the initial receiver locations. The method is based on inverting a series of multidimensional equations of the convolution- and the correlation-type. The required input data can be computed from surface seismic data with a new iterative scheme that is currently being developed. The output data contains virtual sources that illuminate the target not only from above (as in the original data), but also from below, facilitating the needs of seismic imaging and inversion in an optimal way. The method is nonlinear in the sense that all internal multiples are correctly accounted for and true amplitude in the sense that the virtual sources are forced to inherit uniform radiation patterns even though the overburden is strongly heterogeneous.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f752f3d4-5f52-49e6-a309-5786f58dfae8","http://resolver.tudelft.nl/uuid:f752f3d4-5f52-49e6-a309-5786f58dfae8","3D Marine CSEM Interferometry by Multidimensional Deconvolution in the Wavenumber Domain for a Sparse Receiver Grid","Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.","","2013","We use interferometry by multidimensional deconvolution in combination with synthetic aperture sources in 3D to suppress the airwave and the direct field, and to decrease source uncertainty in marine Controlled-Source electromagnetics. We show with this numerical study that the method works for very large receiver spacing distances, even though the thereby retrieved reflection response may be aliased.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:d5828eb0-cde3-4ab5-adcc-07168d34c45e","http://resolver.tudelft.nl/uuid:d5828eb0-cde3-4ab5-adcc-07168d34c45e","Locating scatterers by non-physical scattered waves obtained by seismic interferometry","Harmankaya, U.; Kaslilar, A.; Thorbecke, J.W.; Wapenaar, C.P.A.; Draganov, D.S.","","2013","The investigation and detection of near-surface structures (such as cavities, caves, sinkholes, tunnels, mineshafts, buried objects, archeological ruins, water reservoir, etc.) is important to mitigate geo- and environmental hazards. In a former study, we suggested a method based on active-source seismic interferometry for locating the scatterers and we showed the applicability of the method in a simple model. In our method, we use only one source at the surface and non-physical scattered waves retrieved by seismic interferometry to estimate the location of the scatterer. In this paper, we show the effectiveness of the method in case of lateral variations. We use both scattered body and surface waves to estimate the location of a corner diffractor and a scatterer, respectively, and we obtain very good estimations. The method is promising for near-surface seismic field applications.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience and Engineering","","","","" "uuid:757ea06c-4006-4a60-a03d-31388da7a94d","http://resolver.tudelft.nl/uuid:757ea06c-4006-4a60-a03d-31388da7a94d","Retrieving higher-mode surface waves using seismic interferometry by multidimensional deconvolution","Van Dalen, K.N.; Wapenaar, C.P.A.; Halliday, D.F.","","2013","Virtual-source surface-wave responses can be retrieved using the crosscorrelation of wavefields observed at two receivers. Higher-mode surface waves cannot be properly retrieved when there is a lack of subsurface sources, which is often the case. In this paper, we present a multidimensional-deconvolution scheme that introduces an additional processing step in which the crosscorrelation result is deconvolved by a point-spread function. The scheme is based on an approximate convolution theorem that includes pointforce responses only, which is advantageous for applications with contemporary field-acquisition geometries. The point-spread function captures the imprint of the lack of subsurface sources and quantifies the associated smearing of the virtual source in space and time. The function can be calculated from the same wavefields used in the correlation method, provided that one or more vertical arrays of subsurface receivers are present and the illumination is from one side. We show that the retrieved surface-wave response, including the higher modes, becomes much more accurate. The waveforms are properly reconstructed and there is only a small amplitude error, which is due to non-canceling cross terms in the employed approximate convolution theorem. The improved retrieval of the multi-mode surface waves can facilitate dispersion analyses and near-surface inversion algorithms.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:b67674f6-c10f-4815-8a44-a746b9510521","http://resolver.tudelft.nl/uuid:b67674f6-c10f-4815-8a44-a746b9510521","Creating the green's response to a virtual source inside a medium using reflection data with internal multiples","Broggini, F.; Snieder, R.; Wapenaar, C.P.A.; Thorbecke, J.W.","","2013","Seismic interferometry is a technique that allows one to reconstruct the full wavefield originating from a virtual source inside a medium, assuming a receiver is present at the virtual source location. We discuss a method that creates a virtual source inside a medium from reflection data measured at the surface, without needing a receiver inside the medium and, hence, presenting an advantage over seismic interferometry. An estimate of the direct arriving wavefront is required in addition to the reflection data. However, no information about the medium is needed. We illustrate the method with numerical examples in a lossless acoustic medium with laterally-varying velocity and density. We examine the reconstructed wavefield when a macro model is used to estimate the direct arrivals and we take into consideration finite acquisition aperture. Additionally, a variant of the iterative scheme allows us to decompose the reconstructed wave field into downgoing and upgoing fields. These wave fields are then used to create an image of the medium with either crosscorrelation or multidimensional deconvolution.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c6380fc3-f2f4-484c-ae6e-d11c499990c5","http://resolver.tudelft.nl/uuid:c6380fc3-f2f4-484c-ae6e-d11c499990c5","Electromagnetic interferometry in wavenumber and space domains in a layered earth","Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.","","2013","With interferometry applied to controlled-source electromagnetic data, the direct field and the airwave and all other effects related to the air-water interface can be suppressed in a data-driven way. Interferometry allows for retreival of the scattered field Green’s function of the subsurface or, in other words, the subsurface reflection response. This reflection response can then be further used to invert for the subsurface conductivity distribution. To perform interferometry in 3D, measurements on an areal grid are necessary. We discuss 3D interferometry by multidimensional deconvolution in the frequency-wavenumber and in the frequency-space domains and provide examples for a layered earth model. We use the synthetic aperture source concept to damp the signal at high wavenumbers to allow large receiver sampling distances. Interferometry indeed increases the detectability of a subsurface reservoir. Finally, we discuss the dependency of the accuracy of the retrieved reflection response on the two crucial parameters: the conductivity of the seabed at the receiver location and the stabilization parameter of the least-squares inversion.","electromagnetics; 3D; deconvolution; marine","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:9bccad08-b392-48a1-972e-fe68e4f7eba9","http://resolver.tudelft.nl/uuid:9bccad08-b392-48a1-972e-fe68e4f7eba9","Three-Dimensional Single-Sided Marchenko Inverse Scattering, Data-Driven Focusing, Green’s Function Retrieval, and their Mutual Relations","Wapenaar, C.P.A.; Broggini, F.; Slob, E.C.; Snieder, R.","","2013","The one-dimensional Marchenko equation forms the basis for inverse scattering problems in which the scattering object is accessible from one side only. Here we derive a three-dimensional (3D) Marchenko equation which relates the single-sided reflection response of a 3D inhomogeneous medium to a field inside the medium. We show that this equation is solved by a 3D iterative data-driven focusing method, which yields the 3D Green’s function with its virtual source inside the medium. The 3D single-sided Marchenko equation and its iterative solution method form the basis for imaging of 3D strongly scattering inhomogeneous media that are accessible from one side only.","","en","journal article","American Physical Society","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:52a36d74-1135-4cf6-b843-b5ce2acef15a","http://resolver.tudelft.nl/uuid:52a36d74-1135-4cf6-b843-b5ce2acef15a","On the Retrieval of the Directional Scattering Matrix from Directional Noise","Wapenaar, C.P.A.; Thorbecke, J.W.","","2013","The crosscorrelation of ambient acoustic noise observed at two receivers yields the impulse response between these receivers, assuming that the noise field is diffuse. In practical situations the noise field exhibits directionality, which imprints the angle-dependent correlation function. For the situation of a directional scatterer in a directional noise field, the correlation function contains the product of the directional scattering matrix and the directional noise. This seemingly underdetermined problem can be resolved by exploiting a relation between the causal and acausal parts of the correlation function. For a given pair of receivers, the causal and acausal parts of the correlation function contain the same element of the scattering matrix (by reciprocity) but different elements of the directional noise field. This property can be used to estimate the directionality of the noise (apart from an undetermined scaling factor) and, subsequently, of the scattering matrix","scattering matrix; optical theorem; ambient noise","en","journal article","Society for Industrial and Applied Mathematics (SIAM)","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:f911ba40-d510-42c8-a6bf-d64527330d67","http://resolver.tudelft.nl/uuid:f911ba40-d510-42c8-a6bf-d64527330d67","Seismic interferometry by midpoint integration","Ruigrok, E.N.; Almagro Vidal, C.; Wapenaar, C.P.A.","","2012","With seismic interferometry reflections can be retrieved between station positions. In the classical form, the reflections are retrieved by an integration over sources. For a specific dataset, however, the actual source distribution might not be sufficient to approximate the source integral. Yet, there might be a dense distribution of receivers allowing integration over the receiver domain. We rewrite the source integral to an integration over midpoints. With this formulation, a reflection can be retrieved even in the limiting case of only a single source. However, with respect to the classical formulation, an additional stationary-phase analysis is required.","","en","conference paper","Deutsche Geophysikalische Gesellschaft","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:fe7e739e-0f19-4a77-ba51-6273e92ba199","http://resolver.tudelft.nl/uuid:fe7e739e-0f19-4a77-ba51-6273e92ba199","Focusing the wavefield inside an unknown 1D medium: Beyond seismic interferometry","Broggini, F.; Snieder, R.; Wapenaar, C.P.A.","","2012","With seismic interferometry one can retrieve the response to a virtual source inside an unknown medium, if there is a receiver at the position of the virtual source. Using inverse scattering theory, we demonstrate that, for a 1D medium, the requirement of having an actual receiver inside the medium can be circumvented, going beyond seismic interferometry. In this case, the wavefield can be focused inside an unknown medium with independent variations in velocity and density using reflection data only.","","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:3cc6b08f-a7e1-443a-8c1d-67b461eb915a","http://resolver.tudelft.nl/uuid:3cc6b08f-a7e1-443a-8c1d-67b461eb915a","Global-phase seismic interferometry unveils P-wave reflectivity below the Himalayas and Tibet","Ruigrok, E.N.; Wapenaar, C.P.A.","","2012","A number of seismic methods exist to image the lithosphere below a collection of receivers, using distant earthquakes. In the current practice, especially mode-conversions in teleseismic phases are utilized. We present a new method that takes advantage of the availability of global phases. This method is called global-phase seismic interferometry (GloPSI). With GloPSI, zero-offset reflections are extracted from reverberations near the array caused by global seismicity. We exemplify GloPSI with data from the Hi-CLIMB experiment (2002–2005) and migrate the obtained reflection responses. This results in a 800 km long reflectivity profile through the Himalayas and a large part of the Tibetan Plateau.","","en","journal article","American Geophysical Union","","","","","","","2012-12-05","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:aa01d8e7-7782-48c1-8552-c97bbfdbee67","http://resolver.tudelft.nl/uuid:aa01d8e7-7782-48c1-8552-c97bbfdbee67","Synthesized 2D CSEM-interferometry Using Automatic Source Line Determination","Hunziker, J.W.; Slob, E.C.; Fan, Y.; Snieder, R.; Wapenaar, C.P.A.","","2012","Interferometry by multidimensional deconvolution applied to Controlled-Source Electromagnetic data replaces the medium above the receivers by a homogeneous halfspace, suppresses the direct field and redatums the source positions to the receiver locations. In that sense, the airwave and any other interactions of the signal with the air-water interface and the water layer are suppressed and the source uncertainty is reduced. Interferometry requires grid data and cannot be applied to line data unless the source is infinitely long in the crossline direction. To create such a source, a set of source lines is required. We use an iterative algorithm to determine the optimal locations of these source lines and show that more source lines are required if the source is towed closer to the sea bottom and closer to the receivers.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:be874ea3-2151-43d9-b4f6-59dbd459e091","http://resolver.tudelft.nl/uuid:be874ea3-2151-43d9-b4f6-59dbd459e091","Estimating the Location of Scatterers by Seismic Interferometry of Scattered Surface Waves","Harmankaya, U.; Kaslilar, A.; Thorbecke, J.W.; Wapenaar, C.P.A.; Draganov, D.S.","","2012","In this study, non-physical (ghost) scattered surface waves are used to obtain the location of a near surface scatterer. The ghost is obtained from application of seismic interferometry to only one source at the surface. Different locations for virtual sources are chosen and ghost scattered surface waves for each of these virtual-source locations are retrieved. The retrieved ghost traveltimes are inverted by solving the inverse problem to determine the location of the scatterer. It is seen that the location of the scatterer is reasonably well estimated.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:569fa57f-bd3f-4e26-9c74-f544326125bd","http://resolver.tudelft.nl/uuid:569fa57f-bd3f-4e26-9c74-f544326125bd","Creating Virtual Sources Inside an Unknown Medium from Reflection Data: A New Approach to Internal Multiple Elimination","Wapenaar, C.P.A.; Thorbecke, J.W.; Van der Neut, J.R.; Broggini, F.; Snieder, R.","","2012","It has recently been shown that the response to a virtual source in the subsurface can be derived from reflection data at the surface and an estimate of the direct arrivals between the virtual source and the surface. Hence, unlike for seismic interferometry, no receivers are needed inside the medium. This new method recovers the complete wavefield of a virtual source, including all internal multiple scattering. Because no actual receivers are needed in the medium, the virtual source can be placed anywhere in the subsurface. With some additional processing steps (decomposition and multidimensional deconvolution) it is possible to obtain a redatumed reflection response at any depth level in the subsurface, from which all the overburden effects are eliminated. By applying standard migration between these depth levels, a true amplitude image of the subsurface can be obtained, free from ghosts due to internal multiples. The method is non-recursive and therefore does not suffer from error propagation. Moreover, the internal multiples are eliminated by deconvolution, hence no adaptive prediction and subtraction is required.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5f224a80-69d0-40bf-8cee-7ee22d89afff","http://resolver.tudelft.nl/uuid:5f224a80-69d0-40bf-8cee-7ee22d89afff","A unified optical theorem for scalar and vectorial wave fields","Wapenaar, C.P.A.; Douma, H.","","2012","The generalized optical theorem is an integral relation for the angle-dependent scattering amplitude of an inhomogeneous scattering object embedded in a homogeneous background. It has been derived separately for several scalar and vectorial wave phenomena. Here a unified optical theorem is derived that encompasses the separate versions for scalar and vectorial waves. Moreover, this unified theorem also holds for scattering by anisotropic elastic and piezoelectric scatterers as well as bianisotropic (non-reciprocal) EM scatterers.","acoustic field; acoustic wave scattering; inhomogeneous media","en","journal article","Acoustical Society of America","","","","","","","2012-11-30","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:419c882f-51cc-4723-af40-4ef71fd4b3cd","http://resolver.tudelft.nl/uuid:419c882f-51cc-4723-af40-4ef71fd4b3cd","Deblending by direct inversion","Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.","","2012","Deblending of simultaneous-source data is usually considered to be an underdetermined inverse problem, which can be solved by an iterative procedure, assuming additional constraints like sparsity and coherency. By exploiting the fact that seismic data are spatially band-limited, deblending of densely sampled sources can be carried out as a direct inversion process without imposing these constraints. We applied the method with numerically modeled data and it suppressed the crosstalk well, when the blended data consisted of responses to adjacent, densely sampled sources","acquisition; inversion","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:e23dede0-cc57-464e-ad42-77b49a1bb6e1","http://resolver.tudelft.nl/uuid:e23dede0-cc57-464e-ad42-77b49a1bb6e1","Extraction of P-wave reflections from microseisms","Ruigrok, E.N.; Campman, X.; Wapenaar, K.","","2011","The last few years there has been a growing number of body-wave observations in noise records. In 1973 Vinnik conjectured that P-waves would even be the dominant wavemode, at epicentral distances of about 40 degrees and onwards from an oceanic source. At arrays far from offshore storms, surface waves induced by nearby storms would not mask the body-wave signal and hence primarily P-waves would be recorded. We measured at such an array in Egypt and indeed found a large proportion of P-waves. At the same time, a new methodology is under development to characterize the lithosphere below an array of receivers, without active sources or local earthquakes. Instead, transmitted waves are used which are caused by distant sources. These sources may either be transient or more stationary. With this new methodology, called seismic interferometry, reflection responses are extracted from the coda of transmissions. Combining the two developments it is clear that there is a large potential for obtaining reflection responses from low-frequency noise. A potential practical advantage of using noise instead of earthquake responses would be that an array only needs to be deployed for a few days or weeks instead of months, to gather enough illumination. We used a few days of continuous noise, recorded with an array in the Abu Gharadig basin, Egypt. We split up the record in three distinct frequency bands and in many small time windows. Using array techniques and taking advantage of all three-component recordings we could unravel the dominant wavemodes arriving in each time window and in each frequency band. The recorded wavemodes, and hence the noise sources, varied significantly per frequency band, and -to a lesser extent- per time window. Primarily P-waves were detected on the vertical component for two of the three frequency bands. For these frequency bands, we only selected the time windows with a favorable illumination. By subsequently applying seismic interferometry, we retrieved P-wave reflection responses and delineated reflectors in the crust, the Moho and possibly the Lehmann discontinuity.","body waves; interferometry; ambient noise; microseism; lithosphere","en","journal article","Elsevier","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:55fabcd8-0435-48ba-aba0-a0bad1e05033","http://resolver.tudelft.nl/uuid:55fabcd8-0435-48ba-aba0-a0bad1e05033","Controlled-source interferometric redatuming by crosscorrelation and multidimensional deconvolution in elastic media","Van der Neut, J.R.; Thorbecke, J.W.; Mehta, K.; Slob, E.C.; Wapenaar, C.P.A.","","2011","Various researchers have shown that accurate redatuming of controlled seismic sources to downhole receiver locations can be achieved without requiring a velocity model. By placing receivers in a horizontal or deviated well and turning them into virtual sources, accurate images can be obtained even below a complex near-subsurface. Examples include controlled-source interferometry and the virtual-source method, both based on crosscorrelated signals at two downhole receiver locations, stacked over source locations at the surface. Because the required redatuming operators are taken directly from the data, even multiple scattered waveforms can be focused at the virtual-source location, and accurate redatuming can be achieved. To reach such precision in a solid earth, representations for elastic wave propagation that require multicomponent sources and receivers must be implemented. Wavefield decomposition prior to crosscorrelation allows us to enforce virtual sources to radiate only downward or only upward. Virtual-source focusing and undesired multiples from the overburden can be diagnosed with the interferometric point-spread function (PSF), which can be obtained directly from the data if an array of subsurface receivers is deployed. The quality of retrieved responses can be improved by filtering with the inverse of the PSF, a methodology referred to as multidimensional deconvolution.","acoustic wave interferometry; correlation methods; deconvolution; filtering theory; geophysical signal processing; geophysical techniques; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:5aee14ca-5e05-4fec-9138-dc6f306c1b7c","http://resolver.tudelft.nl/uuid:5aee14ca-5e05-4fec-9138-dc6f306c1b7c","Deghosting, demultiple, and deblurring in controlled-source seismic interferometry","Van der Neut, J.R.; Tatanova, M.; Thorbecke, J.W.; Slob, E.C.; Wapenaar, C.P.A.","","2011","With controlled-source seismic interferometry we aim to redatum sources to downhole receiver locations without requiring a velocity model. Interferometry is generally based on a source integral over cross-correlation (CC) pairs of full, perturbed (time-gated), or decomposed wavefields. We provide an overview of ghosts, multiples, and spatial blurring effects that can occur for different types of interferometry. We show that replacing cross-correlation by multidimensional deconvolution (MDD) can deghost, demultiple, and deblur retrieved data. We derive and analyze MDD for perturbed and decomposed wavefields. An interferometric point spread function (PSF) is introduced that can be obtained directly from downhole data. Ghosts, multiples, and blurring effects that may populate the retrieved gathers can be locally diagnosed with the PSF. MDD of perturbed fields can remove ghosts and deblur retrieved data, but it leaves particular multiples in place. To remove all overburden-related effects, MDD of decomposed fields should be applied.","","en","journal article","Hindawi Publishing Corporation","","","","","","","","Civil Engineering and Geosciences","Applied Geophysics and Petrophysics","","","","" "uuid:db579f8a-3b14-4c1e-949e-d63f883cca2e","http://resolver.tudelft.nl/uuid:db579f8a-3b14-4c1e-949e-d63f883cca2e","Improved surface?wave retrieval from ambient seismic noise by multi?dimensional deconvolution","Wapenaar, C.P.A.; Ruigrok, E.N.; Van der Neut, J.R.; Draganov, D.S.","","2011","The methodology of surface?wave retrieval from ambient seismic noise by crosscorrelation relies on the assumption that the noise field is equipartitioned. Deviations from equipartitioning degrade the accuracy of the retrieved surface?wave Green's function. A point?spread function, derived from the same ambient noise field, quantifies the smearing in space and time of the virtual source of the Green's function. By multidimensionally deconvolving the retrieved Green's function by the point?spread function, the virtual source becomes better focussed in space and time and hence the accuracy of the retrieved surface?wave Green's function may improve significantly. We illustrate this at the hand of a numerical example and discuss the advantages and limitations of this new methodology.","Green's function; ambient noise; surface wave","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:c4772e2c-caae-4123-b4af-c462f23f3489","http://resolver.tudelft.nl/uuid:c4772e2c-caae-4123-b4af-c462f23f3489","Seismic interferometry using multidimensional deconvolution and crosscorrelation for crosswell seismic reflection data without borehole sources","Minato, S.; Matsuoka, T.; Tsuji, T.; Draganov, D.S.; Hunziker, J.W.; Wapenaar, C.P.A.","","2011","Crosswell reflection method is a high-resolution seismic imaging method that uses recordings between boreholes. The need for downhole sources is a restrictive factor in its application, for example, to time-lapse surveys. An alternative is to use surface sources in combination with seismic interferometry. Seismic interferometry (SI) could retrieve the reflection response at one of the boreholes as if from a source inside the other borehole. We investigate the applicability of SI for the retrieval of the reflection response between two boreholes using numerically modeled field data. We compare two SI approaches — crosscorrelation (CC) and multidimensional deconvolution (MDD). SI by MDD is less sensitive to underillumination from the source distribution, but requires inversion of the recordings at one of the receiver arrays from all the available sources. We find that the inversion problem is ill-posed, and propose to stabilize it using singular-value decomposition. The results show that the reflections from deep boundaries are retrieved very well using both the CC and MDD methods. Furthermore, the MDD results exhibit more realistic amplitudes than those from the CC method for downgoing reflections from shallow boundaries. We find that the results retrieved from the application of both methods to field data agree well with crosswell seismic-reflection data using borehole sources and with the logged P-wave velocity.","geophysical techniques; interferometry; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:c43b79fe-1713-4fdc-a310-ee70325cfaff","http://resolver.tudelft.nl/uuid:c43b79fe-1713-4fdc-a310-ee70325cfaff","High-resolution reservoir characterization by an acoustic impedance inversion of a Tertiary deltaic clinoform system in the North Sea","Tetyukhina, D.; Van Vliet, L.J.; Luthi, S.M.; Wapenaar, C.P.A.","","2010","Fluvio-deltaic sedimentary systems are of great interest for explorationists because they can form prolific hydrocarbon plays. However, they are also among the most complex and heterogeneous ones encountered in the subsurface, and potential reservoir units are often close to or below seismic resolution. For seismic inversion, it is therefore important to integrate the seismic data with higher resolution constraints obtained from well logs, whereby not only the acoustic properties are used but also the detailed layering characteristics. We have applied two inversion approaches for poststack, time-migrated seismic data to a clinoform sequence in the North Sea. Both methods are recursive trace-based techniques that use well data as a priori constraints but differ in the way they incorporate structural information. One method uses a discrete layer model from the well that is propagated laterally along the clinoform layers, which are modeled as sigmoids. The second method uses a constant sampling rate from the well data and uses horizontal and vertical regularization parameters for lateral propagation. The first method has a low level of parameterization embedded in a geologic framework and is computationally fast. The second method has a much higher degree of parameterization but is flexible enough to detect deviations in the geologic settings of the reservoir; however, there is no explicit geologic significance and the method is computationally much less efficient. Forward seismic modeling of the two inversion results indicates a good match of both methods with the actual seismic data.","geology; geophysical techniques; hydrocarbon reservoirs; sediments; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:7b865e3f-1f3b-4225-b3d6-97d5f4fca724","http://resolver.tudelft.nl/uuid:7b865e3f-1f3b-4225-b3d6-97d5f4fca724","A representation for Green’s function retrieval by multidimensional deconvolution","Wapenaar, C.P.A.; Van der Neut, J.R.","","2010","Green’s function retrieval by crosscorrelation may suffer from irregularities in the source distribution, asymmetric illumination, intrinsic losses, etc. Multidimensional deconvolution (MDD) may overcome these limitations. A unified representation for Green’s function retrieval by MDD is proposed. From this representation, it follows that the traditional crosscorrelation method gives a Green’s function of which the source is smeared in space and time. This smearing is quantified by a space–time point-spread function (PSF), which can be retrieved from measurements at an array of receivers. MDD removes this PSF and thus deblurs and deghosts the source of the Green’s function obtained by correlation.","","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:bffc466e-3073-47c0-a35d-32c6366ae2bf","http://resolver.tudelft.nl/uuid:bffc466e-3073-47c0-a35d-32c6366ae2bf","High-resolution lithospheric imaging with seismic interferometry","Ruigrok, E.N.; Campman, X.; Draganov, D.S.; Wapenaar, K.","","2010","In recent years, there has been an increase in the deployment of relatively dense arrays of seismic stations. The availability of spatially densely sampled global and regional seismic data has stimulated the adoption of industry-style imaging algorithms applied to converted- and scattered-wave energy from distant earthquakes, leading to relatively high-resolution images of the lower crust and upper mantle.We use seismic interferometry to extract reflection responses from the coda of transmitted energy from distant earthquakes. In theory, higher resolution images can be obtained when migrating reflections obtained with seismic interferometry rather than with conversions, traditionally used in lithospheric imaging methods. Moreover, reflection data allow the straightforward application of algorithms previously developed in exploration seismology. In particular, the availability of reflection data allows us to extract from it a velocity model using standard multichannel data-processing methods. However, the success of our approach relies mainly on a favourable distribution of earthquakes. In this paper, we investigate how the quality of the reflection response obtained with interferometry is influenced by the distribution of earthquakes and the complexity of the transmitted wavefields. Our analysis shows that a reasonable reflection response could be extracted if (1) the array is approximately aligned with an active zone of earthquakes, (2) different phase responses are used to gather adequate angular illumination of the array and (3) the illumination directions are properly accounted for during processing. We illustrate our analysis using a synthetic data set with similar illumination and source-side reverberation characteristics as field data recorded during the 2000–2001 Laramie broad-band experiment. Finally, we apply our method to the Laramie data, retrieving reflection data. We extract a 2-D velocity model from the reflections and use this model to migrate the data. On the final reflectivity image, we observe a discontinuity in the reflections. We interpret this discontinuity as the Cheyenne Belt, a suture zone between Archean and Proterozoic terranes.","seismology; interferometry; body waves; crustal structure","en","journal article","Wiley-Blackwell","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:a7510463-5446-4a49-a8fc-81f44db1d984","http://resolver.tudelft.nl/uuid:a7510463-5446-4a49-a8fc-81f44db1d984","Tutorial on seismic interferometry: Part 1 — Basic principles and applications","Wapenaar, C.P.A.; Draganov, D.S.; Snieder, R.; Campman, X.; Verdel, A.","","2010","Seismic interferometry involves the crosscorrelation of responses at different receivers to obtain the Green's function between these receivers. For the simple situation of an impulsive plane wave propagating along the x-axis, the crosscorrelation of the responses at two receivers along the x-axis gives the Green's function of the direct wave between these receivers. When the source function of the plane wave is a transient (as in exploration seismology) or a noise signal (as in passive seismology), then the crosscorrelation gives the Green's function, convolved with the autocorrelation of the source function. Direct-wave interferometry also holds for 2D and 3D situations, assuming the receivers are surrounded by a uniform distribution of sources. In this case, the main contributions to the retrieved direct wave between the receivers come from sources in Fresnel zones around stationary points. The main application of direct-wave interferometry is theretrieval of seismic surface-wave responses from ambient noise and the subsequent tomographic determination of the surface-wave velocity distribution of the subsurface. Seismic interferometry is not restricted to retrieving direct waves between receivers. In a classic paper, Claerbout shows that the autocorrelation of the transmission response of a layered medium gives the plane-wave reflection response of that medium. This is essentially 1D reflected-wave interferometry. Similarly, the crosscorrelation of the transmission responses, observed at two receivers, of an arbitrary inhomogeneous medium gives the 3D reflection response of that medium. One of the main applications of reflected-wave interferometry is retrieving the seismic reflection response from ambient noise and imaging of the reflectors in the subsurface. A common aspect of direct- and reflected-wave interferometry is that virtual sources are created at positions where there are only receivers without requiring knowledge of the subsurface medium parameters or of the positions of the actual sources.","geophysical techniques; Green's function methods; interferometry; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:07504f32-d9fb-46b9-8095-dcfa5b3e817b","http://resolver.tudelft.nl/uuid:07504f32-d9fb-46b9-8095-dcfa5b3e817b","Tutorial on seismic interferometry: Part 2 — Underlying theory and new advances","Wapenaar, C.P.A.; Slob, E.C.; Snieder, R.; Curtis, A.","","2010","In the 1990s, the method of time-reversed acoustics was developed. This method exploits the fact that the acoustic wave equation for a lossless medium is invariant for time reversal. When ultrasonic responses recorded by piezoelectric transducers are reversed in time and fed simultaneously as source signals to the transducers, they focus at the position of the original source, even when the medium is very complex. In seismic interferometry the time-reversed responses are not physically sent into the earth, but they are convolved with other measured responses. The effect is essentially the same: The time-reversed signals focus and create a virtual source which radiates waves into the medium that are subsequently recorded by receivers. A mathematical derivation, based on reciprocity theory, formalizes this principle: The crosscorrelation of responses at two receivers, integrated over differ-ent sources, gives the Green's function emitted by a virtual source at the position of one of the receivers and observed by the other receiver. This Green's function representation for seismic interferometry is based on the assumption that the medium is lossless and nonmoving. Recent developments, circumventing these assumptions, include interferometric representations for attenuating and/or moving media, as well as unified representations for waves and diffusion phenomena, bending waves, quantum mechanical scattering, potential fields, elastodynamic, electromagnetic, poroelastic, and electroseismic waves. Significant improvements in the quality of the retrieved Green's functions have been obtained with interferometry by deconvolution. A trace-by-trace deconvolution process compensates for complex source functions and the attenuation of the medium. Interferometry by multidimensional deconvolution also compensates for the effects of one-sided and/or irregular illumination.","deconvolution; geophysical techniques; Green's function methods; interferometry; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:82033a15-8402-4b47-b7ae-733b3a1f03ac","http://resolver.tudelft.nl/uuid:82033a15-8402-4b47-b7ae-733b3a1f03ac","Reciprocity Theorems for One-Way Wave Fields in Curvilinear Coordinate Systems","Frijlink, M.; Wapenaar, C.P.A.","","2010","One-way wave equations conveniently describe wave propagation in media with discontinuous and/or rapid variations in one direction, but with smooth and slow variations in the complementary transverse directions. In the past, reciprocity theorems have been developed in terms of one-way wave fields. The boundaries of the integration volumes and the variations of the medium parameters must adhere to strict conditions. The variations must have the smoothness required by pseudodifferential operators, while the boundaries have to be flat. To extend the applicability to nonflat boundaries, this paper formulates one-way wave equations and corresponding reciprocity theorems in terms of curvilinear coordinates of the semiorthogonal (SO) type. In SO coordinate systems, one of the covariant basis vectors is orthogonal to the others, which can be nonorthogonal among each other. The same applies to the contravariant basis vectors. Furthermore, the orthogonal directions coincide; that is, the orthogonal co- and contravariant basis vectors coincide. SO coordinates are characterized by a local property of the basis vectors. An extra specification is necessary to make them conform in any way to nonflat boundaries. This can be done in terms of so-called lateral Cartesian (LC) coordinates. Cartesian coordinates are mapped to LC coordinates by applying an invertible transformation to one coordinate while keeping the others the same. LC coordinates are a straightforward means to describe or conform to nonflat boundaries. Applications of the extended reciprocity theorems include removal of multiple reflections, removal of complex propagation effects, wave field extrapolation, and synthesis of unrecorded data.","reciprocity theorems; curvilinear coordinates; one-way wave fields","en","journal article","Society for Industrial and Applied Mathematics","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:9bf7fc0a-55ba-4cd0-91dd-b51b2064b638","http://resolver.tudelft.nl/uuid:9bf7fc0a-55ba-4cd0-91dd-b51b2064b638","On seismic interferometry, the generalized optical theorem, and the scattering matrix of a point scatterer","Wapenaar, C.P.A.; Slob, E.C.; Snieder, R.","","2010","We have analyzed the far-field approximation of the Green's function representation for seismic interferometry. By writing each of the Green's functions involved in the correlation process as a superposition of a direct wave and a scattered wave, the Green's function representation is rewritten as a superposition of four terms. When the scattered waves are modeled with the Born approximation, it appears that a three-term approximation of the Green's function representation (omitting the term containing the crosscorrelation of the scattered waves) yields a nearly exact retrieval, whereas the full four-term expression leads to a significant nonphysical event. This is because the Born approximation does not conserve energy and therefore is an insufficient model to explain all aspects of seismic interferometry. We use the full four-term expression of the Green's function representation to derive the generalized optical theorem. Unlike other recent derivations, which use stationary phase analysis, our derivation uses reciprocity theory. From the generalized optical theorem, we derive the nonlinear scattering matrix of a point scatterer. This nonlinear model accounts for primary and multiple scattering at the point scatterer and conforms with well-established scattering theory of classical waves. The model is essential to explain fully the results of seismic interferometry, even when it is applied to the response of a single point scatterer. The nonlinear scattering matrix also has implications for modeling, inversion, and migration.","geophysical techniques; Green's function methods; interferometry; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","","" "uuid:84703eac-a050-4e85-bf32-68bbae218732","http://resolver.tudelft.nl/uuid:84703eac-a050-4e85-bf32-68bbae218732","Reflection images from ambient seismic noise","Draganov, D.S.; Campman, X.; Thorbecke, J.W.; Verdel, A.; Wapenaar, C.P.A.","","2009","One application of seismic interferometry is to retrieve the impulse response (Green's function) from crosscorrelation of ambient seismic noise. Various researchers show results for retrieving the surface-wave part of the Green's function. However, reflection retrieval has proven more challenging. We crosscorrelate ambient seismic noise, recorded along eight parallel lines in the Sirte basin east of Ajdabeya, Libya, to obtain shot gathers that contain reflections. We take advantage of geophone groups to suppress part of the undesired surface-wave noise and apply frequency-wavenumber filtering before crosscorrelation to suppress surface waves further. After comparing the retrieved results with data from an active seismic exploration survey along the same lines, we use the retrieved reflection data to obtain a migrated reflection image of the subsurface.","geophysical signal processing; interference suppression; seismic waves; seismology; signal denoising","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:b71c6656-d761-4fb4-b079-5c8f363383e9","http://resolver.tudelft.nl/uuid:b71c6656-d761-4fb4-b079-5c8f363383e9","Ray-based stochastic inversion of prestack seismic data for improved reservoir characterization","Van der Burg, D.; Verdel, A.; Wapenaar, C.P.A.","","2009","Trace inversion for reservoir parameters is affected by angle averaging of seismic data and wavelet distortion on the migration image. In an alternative approach to stochastic trace inversion, the data are inverted prestack before migration using 3D dynamic ray tracing. This choice makes it possible to interweave trace inversion with Kirchhoff migration. The new method, called ray-based stochastic inversion, is a generalization of current amplitude versus offset/amplitude versus angle (AVO/AVA) inversion techniques. The new method outperforms standard stochastic inversion techniques in cases of reservoir parameter estimation in a structurally complex subsurface with substantial lateral velocity variations and significant reflector dips. A simplification of the method inverts the normal-incidence response from reservoirs with approximately planar layering at the subsurface target locations selected for inversion. It operates along raypaths perpendicular to the reflectors, the direction that offers optimal resolution to discern layering in a reservoir. In a test on field data from the Gulf of Mexico, reservoir parameter estimates obtained with the simplified method, the estimates found by conventional stochastic inversion, and the actual values at a well drilled after the inversion are compared. Although the new method uses only 2% of the prestack data, the result indicates it improves accuracy on the dipping part of the reservoir, where conventional stochastic inversion suffers from wavelet stretch caused by migration.","geophysical techniques; hydrocarbon reservoirs; seismic waves; seismology; stochastic processes","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:f8c08807-6c08-4ea5-9be3-87fec54423ad","http://resolver.tudelft.nl/uuid:f8c08807-6c08-4ea5-9be3-87fec54423ad","Virtual reflector representation theorem (acoustic medium)","Poletto, F.; Wapenaar, C.P.A.","","2009","The virtual reflector method simulates new seismic signals by processing traces recorded by a plurality of sources and receivers. The approach is based on the crossconvolution of the recorded signals and makes it possible to obtain the Green’s function of virtual reflected signals as if in the position of the receivers (or sources) there were a reflector, even if said reflector is not present. This letter presents the virtual reflector theory based on the Kirchhoff integral representation theorem for wave propagation in an acoustic medium with and without boundary and a generalization to variable reflection coefficients for scattered wavefields.","acoustic signal processing; boundary-value problems; Green's function methods; seismic waves","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:015bf386-811f-4587-b50b-9bac69f19699","http://resolver.tudelft.nl/uuid:015bf386-811f-4587-b50b-9bac69f19699","Passive seismic interferometry by multidimensional deconvolution","Wapenaar, C.P.A.; Van der Neut, J.R.; Ruigrok, E.N.","","2008","We introduce seismic interferometry of passive data by multidimensional deconvolution (MDD) as an alternative to the crosscorrelation method. Interferometry by MDD has the potential to correct for the effects of source irregularity, assuming the first arrival can be separated from the full response. MDD applications can range from reservoir imaging using microseismicity to crustal imaging with teleseismic data.","deconvolution; geophysical techniques; multidimensional signal processing; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:7d656a13-c0f1-425a-8835-616a1ccfdb0a","http://resolver.tudelft.nl/uuid:7d656a13-c0f1-425a-8835-616a1ccfdb0a","Global-scale seismic interferometry: Theory and numerical examples","Ruigrok, E.N.; Draganov, D.S.; Wapenaar, K.","","2008","Progress in the imaging of the mantle and core is partially limited by the sparse distribution of natural sources; the earthquake hypocenters are mainly along the active lithospheric plate boundaries. This problem can be approached with seismic interferometry. In recent years, there has been considerable progress in the development of seismic interferometric techniques. The term seismic interferometry refers to the principle of generating new seismic responses by cross-correlating seismic observations at different receiver locations. The application of interferometric techniques on a global scale could create sources at locations where no earthquakes occur. In this way, yet unknown responses would become available for the application of travel-time tomography and surface-wave dispersion studies. The retrieval of a dense-enough sampling of source gathers would largely benefit the application of reflection imaging. We derive new elastodynamic representation integrals for global-scale seismic interferometry. The relations are different from other seismic interferometry relations for transient sources, in the sense that they are suited for a rotating closed system like the Earth. We use a correlation of an observed response with a response to which free-surface multiple elimination has been applied to account for the closed system. Despite the fact that the rotation of the Earth breaks source-receiver reciprocity, the seismic interferometry relations are shown to be valid. The Coriolis force is included without the need to evaluate an extra term. We synthesize global-scale earthquake responses and use them to illustrate the acoustic versions of the new interferometric relations. When the sampling of real source locations is dense enough, then both the responses with and without freesurface multiples are retrieved. When we do not take into account the responses from the sources in the direct neighborhood of the seismic interferometry-constructed source location, the response with free-surface multiples can still be retrieved. Even when only responses from sources at a certain range of epicentral distances are available, some events in the Green’s function between two receiver locations can still be retrieved. The retrieved responses are not perfect, but the artefacts can largely be ascribed to numerical errors. The reconstruction of internal events – the response as if there was a source and a receiver on (major) contrasts within the model – could possibly be of use for imaging. With modelling it is possible to discover in which region of the correlation panel stationary phases occur that contribute to the retrieval of events. This knowledge opens up a new way of filtering out undesired events and of discovering whether specific events could be retrieved with a given source-receiver configuration.","seismology; body waves; seismic interferometry","en","journal article","Wiley-Blackwell","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:b68278f6-91fb-471b-9d49-decc2927f766","http://resolver.tudelft.nl/uuid:b68278f6-91fb-471b-9d49-decc2927f766","Simulating migrated and inverted seismic data by filtering a geologic model","Toxopeus, G.; Thorbecke, J.W.; Wapenaar, C.P.A.; Petersen, S.; Slob, E.C.; Fokkema, J.T.","","2008","The simulation of migrated and inverted data is hampered by the high computational cost of generating 3D synthetic data, followed by processes of migration and inversion. For example, simulating the migrated seismic signature of subtle stratigraphic traps demands the expensive exercise of 3D forward modeling, followed by 3D migration of the synthetic seismograms. This computational cost can be overcome using a strategy for simulating migrated and inverted data by filtering a geologic model with 3D spatial-resolution and angle filters, respectively. A key property of the approach is this: The geologic model that describes a target zone is decoupled from the macrovelocity model used to compute the filters. The process enables a target-orientedapproach, by which a geologically detailed earth model describing a reservoir is adjusted without having to recalculate the filters. Because a spatial-resolution filter combines the results of the modeling and migration operators, the simulated images can be compared directly to a real migration image. We decompose the spatial-resolution filter into two parts and show that applying one of those parts produces output directly comparable to 1D inverted real data. Two-dimensional synthetic examples that include seismic uncertainties demonstrate the usefulness of the approach. Results from a real data example show that horizontal smearing, which is not simulated by the 1D convolution model result, is essential to understand the seismic expression of the deformation related to sulfate dissolution and karst collapse.","deformation; geochemistry; seismic waves; seismology; stratigraphy","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:e599c89e-0186-4723-94b5-364e85ddb0af","http://resolver.tudelft.nl/uuid:e599c89e-0186-4723-94b5-364e85ddb0af","On the relation between seismic interferometry and the migration resolution function","Thorbecke, J.W.; Wapenaar, C.P.A.","","2007","Seismic interferometry refers to the process of retrieving new seismic responses by crosscorrelating seismic observations at different receiver locations. Seismic migration is the process of forming an image of the subsurface by wavefield extrapolation. Comparing the expressions for backward propagation known from migration literature with the Green's function representations for seismic interferometry reveals that these seemingly distinct concepts are mathematically equivalent. The frequency-domain representation for the resolution function of migration is identical to that for the Green's function retrieved by seismic interferometry (or its square, in the case of double focusing). In practice, they differ because the involved Green's functions in seismic interferometry are all defined in the actual medium, whereas in migration one of the Green's functions is defined in a background medium.","geophysical techniques; Green's function methods; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:0797113d-e33f-491e-82bd-e23b570903a6","http://resolver.tudelft.nl/uuid:0797113d-e33f-491e-82bd-e23b570903a6","Retrieving reflection responses by crosscorrelating transmission responses from deterministic transient sources: Application to ultrasonic data","Draganov, D.; Wapenaar, K.; Thorbecke, J.; Nishizawa, O.","","2007","By crosscorrelating transmission recordings of acoustic or elastic wave fields at two points, one can retrieve the reflection response between these two points. This technique has previously been applied to measured elastic data using diffuse wave-field recordings. These recordings should be relatively very long. The retrieval can also be achieved by using deterministic transient sources with the advantage of using short recordings, but with the necessity of using many P-wave and S-wave sources. Here, it is shown how reflections were retrieved from the cross correlation of transient ultrasonic transmission data measured on a heterogeneous granite sample.","acoustic signal processing; ultrasonic reflection; ultrasonic transmission","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:a89005f2-07e1-4c2e-b293-20ef631cf2ae","http://resolver.tudelft.nl/uuid:a89005f2-07e1-4c2e-b293-20ef631cf2ae","General representations for wavefield modeling and inversion in geophysics","Wapenaar, C.P.A.","","2007","Acoustic, electromagnetic, elastodynamic, poroelastic, and electroseismic waves are all governed by a unified matrix-vector wave equation. The matrices in this equation obey the same symmetry properties for each of these wave phenomena. This implies that the wave vectors for each of these phenomena obey the same reciprocity theorems. By substituting Green's matrices in these reciprocity theorems, unified wavefield representations are obtained. Analogous to the well-known acoustic wavefield representations, these unified representations find applications in geophysical modeling, migration, inversion, multiple elimination, and interferometry.","acoustic waves; seismic waves; vectors; matrix algebra; interferometry","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:5bf81d4c-d7b2-4c22-8e70-81a00dc17e7c","http://resolver.tudelft.nl/uuid:5bf81d4c-d7b2-4c22-8e70-81a00dc17e7c","Electromagnetic Green's functions retrieval by cross?correlation and cross?convolution in media with losses","Slob, E.C.; Wapenaar, C.P.A.","","2007","It is shown that the electromagnetic Green's functions of any linear medium with arbitrary heterogeneity can be obtained from the cross?correlation, or the cross?convolution, of two recordings at different receiver locations in an open system. Existing representations are known for cross?correlations where time?reversal invariance is exploited and hence they are considered in lossless media. We show here that the cross?correlation type representations are exact in a configuration with sources on a closed boundary and the medium has non?zero loss terms only outside this boundary. Furthermore, we show that for cross?convolution representations the loss mechanisms may exist anywhere in space. Many sources of electromagnetic signals exist in the atmosphere and in populated areas, and these can be used in a large variety of practical passive applications exploiting eddy current or electromagnetic wave techniques.","representation theory; cross-convolution; cross-correlation","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:d16d5860-72e6-45e9-9f56-0cfcb41d86ce","http://resolver.tudelft.nl/uuid:d16d5860-72e6-45e9-9f56-0cfcb41d86ce","Retrieval of reflections from seismic background?noise measurements","Draganov, D.S.; Wapenaar, K.; Mulder, W.; Singer, J.; Verdel, A.","","2007","The retrieval of the earth's reflection response from cross?correlations of seismic noise recordings can provide valuable information, which may otherwise not be available due to limited spatial distribution of seismic sources. We cross?correlated ten hours of seismic background?noise data acquired in a desert area. The cross?correlation results show several coherent events, which align very well with reflections from an active survey at the same location. Therefore, we interpret these coherent events as reflections. Retrieving seismic reflections from background?noise measurements has a wide range of applications in regional seismology, frontier exploration and long?term monitoring of processes in the earth's subsurface.","cross-correlation; Green's function retrieval; reflections; interferometry","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:b8934b2b-1b8e-41dd-95a9-11deed023b0d","http://resolver.tudelft.nl/uuid:b8934b2b-1b8e-41dd-95a9-11deed023b0d","Unified Green's function retrieval by cross-correlation: Connection with energy principles","Snieder, R.; Wapenaar, K.; Wegler, U.","","2007","","","en","journal article","American Physical Society","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:5857194a-8e97-4b28-aaee-e77953dfc4bc","http://resolver.tudelft.nl/uuid:5857194a-8e97-4b28-aaee-e77953dfc4bc","Unified Green’s Function Retrieval by Cross Correlation","Wapenaar, C.P.A.; Slob, E.C.; Snieder, R.","","2006","It has been shown by many authors that the cross correlation of two recordings of a diffuse wave field at different receivers yields the Green’s function between these receivers. Recently the theory has been extended for situations where time-reversal invariance does not hold (e.g., in attenuating media) and where source-receiver reciprocity breaks down (in moving fluids). Here we present a unified theory for Green’s function retrieval that captures all these situations and, because of the unified form, readily extends to more complex situations, such as electrokinetic Green’s function retrieval in poroelastic or piezoelectric media. The unified theory has a wide range of applications in ‘‘remote sensing without a source.’’","","en","journal article","American Physical Society","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:58eadba7-e1bd-4ad8-a24d-40cbd195c444","http://resolver.tudelft.nl/uuid:58eadba7-e1bd-4ad8-a24d-40cbd195c444","Green's function retrieval by cross?correlation in case of one?sided illumination","Wapenaar, C.P.A.","","2006","The cross-correlation of acoustic wave fields at two receivers yields the exact Green's function between these receivers, provided the receivers are surrounded by sources on a closed surface. In most practical situations the sources are located on an open surface and as a consequence the illumination of the receivers is one-sided. In this Letter we discuss the conditions for accurate Green's function retrieval for the situation of one-sided illumination. It appears that the Green's function retrieval method benefits from the fact that the earth is inhomogeneous, without relying on assumptions about disorder.","","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:bc099609-47bd-4ad8-91ad-2a4a9a949c0f","http://resolver.tudelft.nl/uuid:bc099609-47bd-4ad8-91ad-2a4a9a949c0f","Seismic interferometry-turning noise into signal","Curtis, A.; Gerstoft, P.; Sato, H.; Snieder, R.; Wapenaar, C.P.A.","","2006","Turning noise into useful data—every geophysicist's dream? And now it seems possible. The field of seismic interferometry has at its foundation a shift in the way we think about the parts of the signal that are currently filtered out of most analyses—complicated seismic codas (the multiply scattered parts of seismic waveforms) and background noise (whatever is recorded when no identifiable active source is emitting, and which is superimposed on all recorded data). Those parts of seismograms consist of waves that reflect and refract around exactly the same subsurface heterogeneities as waves excited by active sources. The key to the rapid emergence of this field of research is our new understanding of how to unravel that subsurface information from these relatively complex-looking waveforms. And the answer turned out to be rather simple. This article explains the operation of seismic interferometry and provides a few examples of its application.","geophysical techniques; seismology; structural engineering; earthquakes; interferometry","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:c0512fe5-692e-47e3-98a2-a24cf29c0d09","http://resolver.tudelft.nl/uuid:c0512fe5-692e-47e3-98a2-a24cf29c0d09","Spurious multiples in seismic interferometry of primaries","Snieder, R.; Wapenaar, C.P.A.; Larner, K.","","2006","Seismic interferometry is a technique for estimating the Green's function that accounts for wave propagation between receivers by correlating the waves recorded at these receivers. We present a derivation of this principle based on the method of stationary phase. Although this derivation is intended to be educational, applicable to simple media only, it provides insight into the physical principle of seismic interferometry. In a homogeneous medium with one horizontal reflector and without a free surface, the correlation of the waves recorded at two receivers correctly gives both the direct wave and the singly reflected waves. When more reflectors are present, a product of the singly reflected waves occurs in the crosscorrelation that leads to spurious multiples when the waves are excited at the surface only. We give a heuristic argument that these spurious multiples disappear when sources below the reflectors are included. We also extend the derivation to a smoothly varying heterogeneous background medium.","interferometry; seismic waves; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:fc9a5a03-cbfa-40ca-8f4d-9652ecd325f5","http://resolver.tudelft.nl/uuid:fc9a5a03-cbfa-40ca-8f4d-9652ecd325f5","Seismic interferometry: Reconstructing the earth's reflection response","Draganov, D.S.; Wapenaar, C.P.A.; Thorbecke, J.W.","","2006","In 1968, Jon Claerbout showed that the reflection response of a 1D acoustic medium can be reconstructed by autocorrelating the transmission response. Since then, several authors have derived relationships for reconstructing Green's functions at the surface, using crosscorrelations of (noise) recordings that were taken at the surface and that derived from subsurface sources.For acoustic media, we review relations between the reflection response and the transmission response in 3D inhomogeneous lossless media. These relations are derived from a one-way wavefield reciprocity theorem. We use modeling results to show how to reconstruct the reflection response in the presence of transient subsurface sources with distinct excitation times, as well as in the presence of simultaneously acting noise sources in the subsurface. We show that the quality of reconstructed reflections depends on the distribution of the subsurface sources. For a situation with enough subsurface sources — that is, for a distribution that illuminates the subsurface area of interest from nearly alldirections — the reconstructed reflection responses and the migrated depth image exhibit all the reflection events and the subsurface structures of interest, respectively. With only a few subsurface sources, that is, with insufficient illumination, the reconstructed reflection responses are noisy and can even become kinematically incorrect. At the same time, however, the depth image, which was obtained from their migration, still shows clearly all the illuminated subsurface structures at their correct positions.For the elastic case, we review a relationship between the reflection Green's functions and the transmission Green's functions derived from a two-way wavefield reciprocity theorem. Using modeling examples, we show how to reconstruct the different components of the particle velocity observed at the surface and resulting from a surface traction source. This reconstruciton is achieved using crosscorrelations of particle velocity components measured at the surface and resulting from separate P- and S-wave sources in the subsurface.","seismology; interferometry; seismic waves; Green's function methods","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:68e13eb2-52e7-499c-8a04-ddee6fa0d6dd","http://resolver.tudelft.nl/uuid:68e13eb2-52e7-499c-8a04-ddee6fa0d6dd","Green's function representations for seismic interferometry","Wapenaar, C.P.A.; Fokkema, J.T.","","2006","The term seismic interferometry refers to the principle of generating new seismic responses by crosscorrelating seismic observations at different receiver locations. The first version of this principle was derived by Claerbout (1968), who showed that the reflection response of a horizontally layered medium can be synthesized from the autocorrelation of its transmission response. For an arbitrary 3D inhomogeneous lossless medium it follows from Rayleigh's reciprocity theorem and the principle of time-reversal invariance that the acoustic Green's function between any two points in the medium can be represented by an integral of crosscorrelations of wavefield observations at those two points. The integral is along sources on an arbitrarily shaped surface enclosing these points. No assumptions are made with respect to the diffusivity of the wavefield. The Rayleigh-Betti reciprocity theorem leads to a similar representation of the elastodynamic Green's function. When a part of the enclosing surface is the earth's free surface, the integral needs only to be evaluated over the remaining part of the closed surface. In practice, not all sources are equally important: The main contributions to the reconstructed Green's function come from sources at stationary points. When the sources emit transient signals, a shaping filter can be applied to correct for the differences in source wavelets. When the sources are uncorrelated noise sources, the representation simplifies to a direct crosscorrelation of wavefield observations at two points, similar as in methods that retrieve Green's functions from diffuse wavefields in disordered media or in finite media with an irregular bounding surface.","seismology; interferometry; seismic waves; Green's function methods","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:f2026ee0-a023-4c4f-8655-bef577d28c44","http://resolver.tudelft.nl/uuid:f2026ee0-a023-4c4f-8655-bef577d28c44","Introduction to the supplement on seismic interferometry","Wapenaar, C.P.A.; Draganov, D.S.; Robertsson, J.","","2006","","","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:810a9ed6-3572-4271-b99a-183b0afe3f7f","http://resolver.tudelft.nl/uuid:810a9ed6-3572-4271-b99a-183b0afe3f7f","Nonreciprocal Green’s function retrieval by cross correlation","Wapenaar, C.P.A.","","2006","The cross correlation of two recordings of a diffuse acoustic wave field at different receivers yields the Green’s function between these receivers. In nearly all cases considered so far the wave equation obeys time-reversal invariance and the Green’s function obeys source-receiver reciprocity. Here the theory is extended for nonreciprocal Green’s function retrieval in a moving medium. It appears that the cross correlation result is asymmetric in time. The causal part represents the Green’s function from one receiver to the other whereas the acausal part represents the time-reversed version of the Green’s function along the reverse path.","acoustic field; acoustic wave scattering; Green's function methods; wave equations","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:c3fd77aa-1a0f-4a71-92d2-86a722ed1366","http://resolver.tudelft.nl/uuid:c3fd77aa-1a0f-4a71-92d2-86a722ed1366","Retrieving the Green’s function in an open system by cross correlation: A comparison of approaches (L)","Wapenaar, C.P.A.; Fokkema, J.; Snieder, R.","","2005","We compare two approaches for deriving the fact that the Green’s function in an arbitrary inhomogeneous open system can be obtained by cross correlating recordings of the wave field at two positions. One approach is based on physical arguments, exploiting the principle of time-reversal invariance of the acoustic wave equation. The other approach is based on Rayleigh’s reciprocity theorem. Using a unified notation, we show that the result of the time-reversal approach can be obtained as an approximation of the result of the reciprocity approach.","Green's function methods; acoustic wave propagation; acoustic wave scattering; vibrations; structural acoustics; acoustic signal processing; seismology","en","journal article","Acoustical Society of America","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:29ed1385-a3fc-4c09-b5db-9de3255a8482","http://resolver.tudelft.nl/uuid:29ed1385-a3fc-4c09-b5db-9de3255a8482","Retrieving the elastodynamic green's function of an arbitrary inhomogeneous medium by cross correlation","Wapenaar, K.","","2004","","","en","journal article","American Physical Society","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:657c2275-53f4-4fee-a4ed-2cedcd302446","http://resolver.tudelft.nl/uuid:657c2275-53f4-4fee-a4ed-2cedcd302446","Seismische reflecties","Wapenaar, C.P.A.","","2001","","Intreerede","nl","public lecture","","","","","","","","","","","","","","" "uuid:81188ea4-9904-4760-8771-ab83a58f3650","http://resolver.tudelft.nl/uuid:81188ea4-9904-4760-8771-ab83a58f3650","Dynamics of classical wave scattering by small obstacles","Bauer, G.E.W.; Ferreira, M.S.; Wapenaar, C.P.A.","","2001","","","en","journal article","American Physical Society","","","","","","","","","","","","","" "uuid:42a624a7-721a-4b12-a06c-b1254e16fff4","http://resolver.tudelft.nl/uuid:42a624a7-721a-4b12-a06c-b1254e16fff4","A proposal for 4D seismic imaging","Fokkema, J.T.; Dillen, M.W.P.; Wapenaar, C.P.A.","","1997","","development earthquakes elastic waves equations Europe four dimensional models geologic hazards geophysical methods Green function heavy oil induced earthquakes land subsidence measurement while drilling monitoring natural gas Netherlands northern Netherl","en","conference paper","European Association of Geoscientists and Engineers (EAGE), International","","","","","","","","","","","","","" "uuid:c31a699b-f406-4235-ac85-df9b933becbf","http://resolver.tudelft.nl/uuid:c31a699b-f406-4235-ac85-df9b933becbf","The reflectivity operator for curved interfaces","Fokkema, J.T.; Van Vroonhoven, M.; Wapenaar, C.P.A.; De Bruin, C.G.M.","","1993","","boundary conditions curved seismic interface elastic waves geophysical methods heterogeneous materials homogeneous materials mathematical methods reflection seismic methods seismic waves two dimensional models 20 Applied geophysics","en","conference paper","Society of Exploration Geophysicists","","","","","","","","","","","","","" "uuid:3db3eeb2-7663-42cc-bb72-a8aa1c10a67e","http://resolver.tudelft.nl/uuid:3db3eeb2-7663-42cc-bb72-a8aa1c10a67e","Extrapolation operators by beam tracing","Kremer, S.R.G.; Fokkema, J.T.; Wapenaar, C.P.A.","","1991","","amplitude beam tracing data processing extrapolation geophysical methods imagery seismic methods 20 Applied geophysics","en","conference paper","","","","","","","","","","","","","","" "uuid:68eea8de-85ef-4630-bae8-409e46402940","http://resolver.tudelft.nl/uuid:68eea8de-85ef-4630-bae8-409e46402940","Beam tracing for migration and inversion","Fokkema, J.T.; Kremer, S.R.G.; Wapenaar, C.P.A.","","1990","","accuracy direct problem evaluation geophysical methods Green function inverse problem propagation raypaths seismic methods seismic migration 20 Applied geophysics","en","conference paper","","","","","","","","","","","","","","" "uuid:04e20e93-964d-4e3c-9b70-6eafc43a888d","http://resolver.tudelft.nl/uuid:04e20e93-964d-4e3c-9b70-6eafc43a888d","Pre-stack migration in two and three dimensions","Wapenaar, C.P.A.","Berkhout, A.J. (promotor)","1986","","","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","","","","","" "uuid:03efef4f-1a9c-4954-8ca1-fcd61f4ab6b3","http://resolver.tudelft.nl/uuid:03efef4f-1a9c-4954-8ca1-fcd61f4ab6b3","Deghosting, demultiple, and deblurring in controlled-source seismic interferometry","Van der Neut, J.; Tatanova, M.; Thorbecke, J.; Slob, E.; Wapenaar, K.","","","With controlled-source seismic interferometry we aim to redatum sources to downhole receiver locations without requiring a velocity model. Interferometry is generally based on a source integral over cross-correlation (CC) pairs of full, perturbed (timegated), or decomposed wavefields. We provide an overview of ghosts, multiples, and spatial blurring effects that can occur for different types of interferometry. We show that replacing cross-correlation by multidimensional deconvolution (MDD) can deghost, demultiple, and deblur retrieved data. We derive and analyze MDD for perturbed and decomposed wavefields. An interferometric point spread function (PSF) is introduced that can be obtained directly from downhole data. Ghosts, multiples, and blurring effects that may populate the retrieved gathers can be locally diagnosed with the PSF. MDD of perturbed fields can remove ghosts and deblur retrieved data, but it leaves particular multiples in place. To remove all overburden-related effects, MDD of decomposed fields should be applied.","","en","journal article","Hindawi Publishing Corporation","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","","","" "uuid:fc6ffb9d-1639-4827-9f8c-85d94a74bd2e","http://resolver.tudelft.nl/uuid:fc6ffb9d-1639-4827-9f8c-85d94a74bd2e","Time-lapse controlled-source electromagnetics using interferometry","Hunziker, J.W.; Slob, E.C.; Wapenaar, C.P.A.","","","In time-lapse controlled-source electromagnetics, it is crucial that the source and the receivers are positioned at exactly the same location at all times of measurement. We use interferometry by multidimensional deconvolution (MDD) to overcome problems in repeatability of the source location. Interferometry by MDD redatums the source to a receiver location and replaces the medium above the receivers with a homogeneous half-space. In this way, changes in the source position and changes of the conductivity in the water-layer become irrelevant. The only remaining critical parameter to ensure a good repeatability of a controlled-source electro-magnetic measurement is the receiver position.","bathymetry; deconvolution; electromagnetic wave interferometry; geophysical prospecting; hydrocarbon reservoirs","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""