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Transdimensional ambient-noise surface wave tomography of the Reykjanes Peninsula, SW Iceland

Rahimi Dalkhani, A. (author), Áústsdóttir, Thorbjörg (author), Gudnason, Egill Árni (author), Hersir, Gylfi Páll (author), Zhang, Xin (author), Weemstra, C. (author)

Ambient noise seismic tomography has proven to be an effective tool for subsurface imaging, particularly in volcanic regions such as the Reykjanes Peninsula (RP), SW Iceland, where ambient seismic noise is ideal with isotropic illumination. The primary purpose of this study is to obtain a reliable shear wave velocity model of the RP, to get a...

journal article 2023

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Imaging of post-collisional deformations on the NE Tisza continental unit using ambient seismic noise: A case study from the Țicău area, Romania

Panea, Ionelia (author), Draganov, D.S. (author), Bouaru, Catalin Florin (author), Munteanu, Ioan (author)

The Ţicău area (NW Romania) is part of the collisional zone between the Tisza and Dacia mega-units. Imaging of Ţicău area's subsurface geological structure will contribute to the understanding of the processes, which controlled its tectonic evolution. Analysis of outcrops provides accurate information for the building of kinematic sections...

journal article 2023

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Wavefield focusing using a generalised, potentially asymmetric homogeneous Green's function

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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The ultimate performance of the Rasnik 3-point alignment system

van der Graaf, H. (author), Bertolini, Alessandro (author), van Heijningen, Joris (author), Bouwens, Bram (author), de Gaay Fortman, Nelson (author), van der Reep, Tom (author), Otemann, Lennart (author)

The Rasnik system is a 3-point optical displacement monitor with sub-nanometer precision. The CCD-Rasnik alignment system was developed in 1993 for monitoring the alignment of the muon chambers of the ATLAS Muon Spectrometer at CERN. Since then, the development has continued as new CMOS imaging pixel chips became available. In this work the...

journal article 2023

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Wide-Swath Ocean Altimetry Using Multi-Satellite Single-Pass Interferometry

Theodosiou, A. (author), Kleinherenbrink, M. (author), López-Dekker, Paco (author)

Estimating sea surface height using cross-track interferometry (XTI) requires high sensitivity because the ocean surface signal is in the order of 10 cm. In addition, the interferometer requires a temporal delay of a few milliseconds to ensure the coherency of the moving ocean surface. We show that a squinted line of sight (LoS), in...

journal article 2023

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Electrically induced liquid-liquid phase transition in a floating water bridge identified by refractive index variations

Fuchs, Elmar C. (author), Woisetschläger, Jakob (author), Wexler, Adam D. (author), Pecnik, Rene (author), Vitiello, Giuseppe (author)

A horizontal electrohydrodynamic (EHD) liquid bridge (also known as a “floating water bridge”) is a phenomenon that forms when high voltage DC (kV·cm^-1) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts as a cylindrical lens and refracts light. Using an...

journal article 2021

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Adaptation of the iterative Marchenko scheme for imperfectly sampled data

van IJsseldijk, J.E. (author), Wapenaar, C.P.A. (author)

The Marchenko method retrieves the responses to virtual sources in the Earth's subsurface from reflection data at the surface, accounting for all orders of multiple reflections. The method is based on two integral representations for focusing- A nd Green's functions. In discretized form, these integrals are represented by finite summations...

journal article 2021

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Holographic wavefield imaging for surface reconstruction and 3d tomography

van Rooij, J. (author)

Optical imaging is the imaging of objects with visible light. It is a tool often used for diagnostic purposes, such as in biomedical and material sciences. Digital holography is an optical imaging technique that captures and images the amplitude as well as the phase (the complex amplitude) of the lightwave. An advantage is that the complex...

doctoral thesis 2020

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Coda-Wave Monitoring of Continuously Evolving Material Properties

Zotz-Wilson, R.D. (author)

We all monitor the world around us through waves. After about sixteen weeks in the womb, the ears and eyes of an infant child begin to deliver the first signals of light and sound waves to the brain. In fact, one could argue that consciousness itself is the feeling one receives when processing large amounts of wavefield data. Despite the...

doctoral thesis 2020

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Marchenko Focusing Without Up/Down Decomposition

Wapenaar, C.P.A. (author)

Current Marchenko algorithms require up/down separation, and solving the Marchenko equation enables one to retrieve the up/down components of the Green's function. We propose an iterative scheme to relax the need for up/down separation for focusing. By presenting a visual tour, we show how to retrieve the Green's function in the subsurface at...

conference paper 2020

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Elastodynamic single-sided homogeneous Green’s function representation: Theory and numerical examples

Reinicke Urruticoechea, C. (author), Wapenaar, C.P.A. (author)

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...

journal article 2019

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Controlled-source seismic reflection interferometry: Virtual-source retrieval, survey infill and identification of surface multiples

Boullenger, B. (author)

The theory of seismic interferometry predicts that the cross-correlation (and possibly summation) between seismic recordings at two separate receivers allows the retrieval of an estimate of the inter-receiver response, or Green's function, from a virtual source at one of the receiver positions. Ideally, the recordings must consist of the...

doctoral thesis 2017

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Full-field multidimensional deconvolution to retrieve body-wave reflections from sparse passive sources

Hartstra, I.E. (author), Almagro Vidal, C. (author), Wapenaar, C.P.A. (author)

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...

journal article 2017

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Deep ocean sound speed characteristics passively derived from the ambient acoustic noise field

Evers, L.G. (author), Wapenaar, C.P.A. (author), Heaney, KD (author), Snellen, M. (author)

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...

journal article 2017

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Long-range correlations of microseism-band pressure fluctuations in the ocean

Ball, Justin S. (author), Godin, Oleg A. (author), Evers, L.G. (author), Lv, Cheng (author)

We investigate the spatial coherence of underwater ambient noise using a yearlong time-series measured off Ascension Island. Qualitative agreement with observed cross-correlations is achieved using a simple range-dependent model, constrained by earlier, active tomographic studies in the area. In particular, the model correctly predicts the...

journal article 2016

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Coupled poroelastic waves and electromagnetic fields in layered media: Theory, Modeling, and Interferometric Synthesis

Grobbe, N. (author)

In this thesis, I study coupled poroelastic waves and electromagnetic fields in layered media. The focus is two-fold:<br/>1. Increase the theoretical and physical understanding of the seismo-electromagnetic phenomenon by analytically-based numerical modeling.<br/>2. Investigate the potential of seismo-electromagnetic interferometry.<br/><br/...

doctoral thesis 2016

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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. (author), Thorbecke, J.W. (author), van der Neut, J.R. (author)

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...

journal article 2016

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Two-receiver measurements of phase velocity: cross-validation of ambient-noise and earthquake-based observations

Kästle, Emanuel D. (author), Soomro, Riaz (author), Weemstra, C. (author), Boschi, Lapo (author), Meier, Thomas (author)

Phase velocities derived from ambient-noise cross-correlation are compared with phase velocities calculated from cross-correlations of waveform recordings of teleseismic earthquakes whose epicentres are approximately on the station–station great circle. The comparison is conducted both for Rayleigh and Love waves using over 1000 station pairs in...

journal article 2016

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Combination of surface and borehole seismic data for robust target-oriented imaging

Liu, Yi (author), van der Neut, J.R. (author), Arntsen, B (author), Wapenaar, C.P.A. (author)

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...

journal article 2016

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On estimating attenuation from the amplitude of the spectrally whitened ambient seismic field

Weemstra, C. (author), Westra, W. (author), Snieder, R. (author), Boschi, L. (author)

Measuring attenuation on the basis of interferometric, receiver-receiver surface waves is a non-trivial task: the amplitude, more than the phase, of ensemble-averaged cross-correlations is strongly affected by non-uniformities in the ambient wavefield. In addition, ambient noise data are typically pre-processed in ways that affect the amplitude...

journal article 2014