"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"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: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: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: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: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: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: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: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: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","","","",""