Searched for: author%3A%22Wapenaar%2C+C.P.A.%22
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Diekmann, Leon (author), Vasconcelos, Ivan (author), Wapenaar, C.P.A. (author), Slob, E.C. (author), Snieder, Roel (author)
Marchenko-type integrals typically relate so-called focusing functions and Green's functions via the reflection response measured on the open surface of a volume of interest. Originating from one dimensional inverse scattering theory, the extension to two and three dimensions set in motion various new developments regarding imaging in complex...
journal article 2023
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Wapenaar, C.P.A. (author)
Classical acoustic wave-field representations consist of volume and boundary integrals, of which the integrands contain specific combinations of Green's functions, source distributions, and wave fields. Using a unified matrix-vector wave equation for different wave phenomena, these representations can be reformulated in terms of Green's matrices...
journal article 2022
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van der Neut, J.R. (author), Brackenhoff, J. (author), Meles, Giovanni Angelo (author), Slob, E.C. (author), Wapenaar, C.P.A. (author)
Green’s functions in an unknown elastic layered medium can be retrieved from single-sided reflection data by solving a Marchenko equation. This methodology requires a priori knowledge of all forward-scattered (non-converted and converted) waveforms. Moreover, the medium should satisfy stringent monotonicity conditions, which are often not met in...
conference paper 2022
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Meles, G.A. (author), Reinicke, Christian (author), Dukalski, M (author), Wapenaar, C.P.A. (author)
Marchenko redatuming retrieves Green’s functions inside an unknown medium, by solving a set of coupled Marchenko equations, which are derived from an under-determined system of equation and two temporal truncations. To constrain the problem, two assumptions are made, which hold reasonably well for acoustic, but not for elastodynamic waves. First...
conference paper 2022
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Dukalski, M (author), Reinicke, Christian (author), Wapenaar, C.P.A. (author)
The presence of evanescent modes and their impact on the Marchenko method has been until very recently a topic that received little attention. In this contribution we link the concept of the transfer matrix to the fields usually associated with the Marchenko method. Using that formalism, we introduce the concept of a path reversal - a...
conference paper 2022
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Wapenaar, C.P.A. (author), de Ridder, Sjoerd (author), Dukalski, Marcin (author), Reinicke, Christian (author)
Standard Marchenko redatuming and imaging schemes neglect evanescent waves and are based on the assumption that decomposition into downgoing and upgoing waves is possible in the subsurface. Recently we have shown that propagator matrices, which circumvent these assumptions, can be expressed in terms of Marchenko focusing functions. In this paper...
conference paper 2022
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Dukalski, Marcin (author), Reinicke, Christian (author), Wapenaar, C.P.A. (author)
Marchenko equation-based methods promise data-driven, true-amplitude internal multiple elimination. The method is exact in 1-D acoustic media, however it needs to be expanded to account for the presence of 2- and 3-D elastodynamic wave-field phenomena, such as compressional (P) to shear (S) mode conversions, total reflections or evanescent waves...
conference paper 2022
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Shoja, S.M. Aydin (author), van der Neut, J.R. (author), Wapenaar, C.P.A. (author)
Geophysicists have widely used Least-squares reverse-time migration (LSRTM) to obtain high-resolution images of the subsurface. However, LSRTM is computationally expensive and it can suffer from multiple reflections. Recently, a target-oriented approach to LSRTM has been proposed, which focuses the wavefield above the target of interest....
journal article 2022
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Shoja, S.M. Aydin (author), van der Neut, J.R. (author), Wapenaar, C.P.A. (author)
Least-squares reverse time migration (LSRTM) is a common imaging technique that geophysicists have been using to obtain high-resolution images. Nevertheless, the high computational cost shifted the focus of researchers to the target-oriented approach. In this approach, by limiting the computational grid to a relatively smaller region, the...
conference paper 2022
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Al Hasani, M.M.K. (author), Drijkoningen, G.G. (author), Wapenaar, C.P.A. (author)
In a surface-seismic setting, Distributed Acoustic Sensing (DAS) is still not a widely adopted method for near-surface characterisation, especially for reflection seismic imaging, despite the dense spatial sampling it provides over long distances. This is mainly due to the decreased broadside sensitivity that DAS suffers from when buried...
conference paper 2022
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Brackenhoff, J.A. (author), Thorbecke, J.W. (author), Meles, G.A. (author), Koehne, Victor (author), Barrera, Diego (author), Wapenaar, C.P.A. (author)
We implement the 3D Marchenko equations to retrieve responses to virtual sources inside the subsurface. For this, we require reflection data at the surface of the Earth that contain no free-surface multiples and are densely sampled in space. The required 3D reflection data volume is very large and solving the Marchenko equations requires a...
journal article 2022
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van der Neut, J.R. (author), Brackenhoff, Joeri (author), Meles, Giovanni Angelo (author), Slob, E.C. (author), Wapenaar, C.P.A. (author)
By solving a Marchenko equation, Green’s functions at an arbitrary (inner) depth level inside an unknown elastic layered medium can be retrieved from single-sided reflection data, which are collected at the top of the medium. To date, it has only been possible to obtain an exact solution if the medium obeyed stringent monotonicity conditions and...
journal article 2022
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Wapenaar, C.P.A. (author), Slob, E.C. (author)
Inspired by recent developments in wave propagation and scattering experiments with parity-time (PT) symmetric materials, we discuss reciprocity and representation theorems for 3D inhomogeneous PT-symmetric materials and indicate some applications. We start with a unified matrix-vector wave equation which accounts for acoustic, quantum...
journal article 2022
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van der Neut, J.R. (author), Brackenhoff, J.A. (author), Meles, G.A. (author), Zhang, L. (author), Slob, E.C. (author), Wapenaar, C.P.A. (author)
A Green's function in an acoustic medium can be retrieved from reflection data by solving a multidimensional Marchenko equation. This procedure requires a priori knowledge of the initial focusing function, which can be interpreted as the inverse of a transmitted wavefield as it would propagate through the medium, excluding (multiply)...
journal article 2022
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Kiraz, Mert S. R. (author), Snieder, Roel (author), Wapenaar, C.P.A. (author)
The Gel'fand-Levitan equation, the Gopinath-Sondhi equation, and the Marchenko equation are developed for one-dimensional inverse scattering problems. Recently, a version of the Marchenko equation based on wavefield decomposition has been introduced for focusing waves in multi dimensions. However, wavefield decomposition is a limitation when...
journal article 2021
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Shirmohammadi, F. (author), Draganov, D.S. (author), Wapenaar, C.P.A. (author)
Seismic interferometry (SI) refers to the principle of generating seismic responses by crosscorrelating seismic observations at different receiver locations. Theory requires that the boundary sources emit the same energy, have regular spacing and are spaced densely enough. When these assumptions are not met, not only the desired physical...
poster 2021
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van IJsseldijk, J.E. (author), Wapenaar, C.P.A. (author)
4D seismic studies aim to observe time-lapse changes in the subsurface between a baseline and a monitor study. These changes are generally small, and the seismic response from a deep reservoir can be concealed by reflections from shallow structures. Here, we introduce a novel way of isolating the reservoir response by means of the Marchenko...
book chapter 2021
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Wapenaar, C.P.A. (author), Ridder, Sjoerd de (author)
The propagator matrix “propagates” a full wave field from one depth level to another, accounting for all propagation angles and evanescent waves. The Marchenko focusing function forms the nucleus of data-driven Marchenko redatuming and imaging schemes, accounting for internal multiples. These seemingly different concepts appear to be closely...
journal article 2021
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Kiraz, Mert S. R. (author), Snieder, Roel (author), Wapenaar, C.P.A. (author)
Marchenko algorithms retrieve the Green’s function for arbitrary subsurface locations, and the retrieved Green’s function includes the primary and multiple reflected waves. The Marchenko algorithms require the estimate of the direct arrivals and the reflected waves; however, most previous Marchenko algorithms also require the up/down components...
book chapter 2021
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Brackenhoff, J.A. (author), Thorbecke, J.W. (author), Wapenaar, C.P.A. (author)
We create virtual sources and receivers in a 3-D subsurface using the previously derived single-sided homogeneous Green's function representation. We employ Green's functions and focusing functions that are obtained using reflection data at the Earth's surface, a macrovelocity model, and the Marchenko method. The homogeneous Green's function is...
journal article 2021
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