"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:c9de6483-2a05-4f05-a25f-cba2cf92ddb6","http://resolver.tudelft.nl/uuid:c9de6483-2a05-4f05-a25f-cba2cf92ddb6","Elastodynamic single-sided homogeneous Green’s function representation: Theory and numerical examples","Reinicke Urruticoechea, C. (TU Delft Applied Geophysics and Petrophysics); Wapenaar, C.P.A. (TU Delft ImPhys/Acoustical Wavefield Imaging; TU Delft Applied Geophysics and Petrophysics)","","2019","The homogeneous Green’s function is the difference between an impulse response and its time-reversal. According to existing representation theorems, the homogeneous Green’s function associated with source–receiver pairs inside a medium can be computed from measurements at a boundary enclosing the medium. However, in many applications such as seismic imaging, time-lapse monitoring, medical imaging, non-destructive testing, etc., media are only accessible from one side. A recent development of wave theory has provided a representation of the homogeneous Green’s function in an elastic medium in terms of wavefield recordings at a single (open) boundary. Despite its single-sidedness, the elastodynamic homogeneous Green’s function representation accounts for all orders of scattering inside the medium. We present the theory of the elastodynamic single-sided homogeneous Green’s function representation and illustrate it with numerical examples for 2D laterally-invariant media. For propagating waves, the resulting homogeneous Green’s functions match the exact ones within numerical precision, demonstrating the accuracy of the theory. In addition, we analyse the accuracy of the single-sided representation of the homogeneous Green’s function for evanescent wave tunnelling.","Elastic; Interferometry; Internal multiples; Layered; Numerical","en","journal article","","","","","","Accepted Author Manuscript","","2021-04-17","","","","","",""
"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:aeefaee3-3d1f-48f8-b9a2-131971ca5e55","http://resolver.tudelft.nl/uuid:aeefaee3-3d1f-48f8-b9a2-131971ca5e55","Combination of surface and borehole seismic data for robust target-oriented imaging","Liu, Yi (Norwegian University of Science and Technology); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics); Arntsen, B; Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)","","2016","A novel application of seismic interferometry (SI) and Marchenko imaging using both surface and borehole data is presented. A series of redatuming schemes is proposed to combine both data sets for robust deep local imaging in the presence of velocity uncertainties. The redatuming schemes create a virtual acquisition geometry where both sources and receivers lie at the horizontal borehole level, thus only a local velocity model near the borehole is needed for imaging, and erroneous velocities in the shallow area have no effect on imaging around the borehole level. By joining the advantages of SI and Marchenko imaging, a macrovelocity model is no longer required and the proposed schemes use only single-component data. Furthermore, the schemes result in a set of virtual data that have fewer spurious events and internal multiples than previous virtual source redatuming methods. Two numerical examples are shown to illustrate the workflow and to demonstrate the benefits of the method. One is a synthetic model and the other is a realistic model of a field in the North Sea. In both tests, improved local images near the boreholes are obtained using the redatumed data without accurate velocities, because the redatumed data are close to the target.","Inverse theory; Downhole methods; Interferometry; Wave propagation","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""
"uuid:3b45c9ec-e3da-4997-8f92-e89271b442c9","http://resolver.tudelft.nl/uuid:3b45c9ec-e3da-4997-8f92-e89271b442c9","A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval","Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics); Thorbecke, J.W. (TU Delft Applied Geophysics and Petrophysics); van der Neut, J.R. (TU Delft Applied Geophysics and Petrophysics)","","2016","Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's function of the wave equation without a singularity on the right-hand side) is represented by a closed boundary integral. In practical applications, sources and/or receivers are usually present only on an open surface, which implies that a significant part of the closed boundary integral is by necessity ignored. Here we derive a homogeneous Green's function representation for the common situation that sources and/or receivers are present on an open surface only. We modify the integrand in such a way that it vanishes on the part of the boundary where no sources and receivers are present. As a consequence, the remaining integral along the open surface is an accurate single-sided representation of the homogeneous Green's function. This single-sided representation accounts for all orders of multiple scattering. The new representation significantly improves the aforementioned wavefield imaging applications, particularly in situations where the first-order scattering approximation breaks down.","Controlled source seismology; Interferometry; Wave scattering and diffraction","en","journal article","","","","","","","","","","","Applied Geophysics and Petrophysics","","",""