Full Waveform Inversion for Seismic Velocity and Anelastic Losses in Heterogeneous Structures

Askan, Ayşegül; Akçelik, Volkan; Bielak, Jacobo; Ghattas, Omar

doi:10.1785/0120070079

Cited by 71 publications

(34 citation statements)

References 61 publications

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“…With the new generation of modelling tools we can go beyond classical tomography by using fully 3‐D initial models (e.g. Akçelik et al 2002, 2003; Askan et al 2007; Chen et al 2007; Fichtner et al 2009b; Fichtner 2010), and utilizing as much information contained in seismograms as possible (e.g. Maggi et al 2009; Valentine & Woodhouse 2010).…”

Section: Discussionmentioning

confidence: 99%

Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes

Peter¹,

Komatitsch

Luo³

et al. 2011

Geophysical Journal International

294

184

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International audienceWe present forward and adjoint spectral-element simulations of coupled acoustic and (an)elastic seismic wave propagation on fully unstructured hexahedral meshes. Simulations benefit from recent advances in hexahedral meshing, load balancing and software optimization. Meshing may be accomplished using a mesh generation tool kit such as CUBIT, and load balancing is facilitated by graph partitioning based on the SCOTCH library. Coupling between fluid and solid regions is incorporated in a straightforward fashion using domain decomposition. Topography, bathymetry and Moho undulations may be readily included in the mesh, and physical dispersion and attenuation associated with anelasticity are accounted for using a series of standard linear solids. Finite-frequency Fr'echet derivatives are calculated using adjoint methods in both fluid and solid domains. The software is benchmarked for a layercake model. We present various examples of fully unstructured meshes, snapshots of wavefields and finite-frequency kernels generated by Version 2.0 'Sesame' of our widely used open source spectral-element package SPECFEM3D

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Section: Discussionmentioning

confidence: 99%

Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes

Peter¹,

Komatitsch

Luo³

et al. 2011

Geophysical Journal International

294

184

View full text Add to dashboard Cite

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“…Here, we use the Zhang et al (2005) relationships for the equivalent-linear site-response calculations in SHAKE, because they have a reasonable number of input parameters (confining pressure, plasticity index, and soil type), and others have also found the Zhang et al (2005) relationships to be broadly applicable (e.g., Askan et al, 2007;Fairbanks et al, 2008;Mondal et al, 2012). The Zhang et al (2005) modulus-reduction and damping relationships were used to model the stress-strain response of the soil at depths above the soil-bedrock interface, Z rock (the depth to the first rock layer in the KiK-net geologic profile, given in Ⓔ Table S1 in the electronic supplement to this article).…”

Section: Site-response Analysesmentioning

confidence: 99%

Critical Parameters Affecting Bias and Variability in Site-Response Analyses Using KiK-net Downhole Array Data

Kaklamanos¹,

Bradley²,

Thompson³

et al. 2013

Bulletin of the Seismological Society of America

163

110

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Because of the limited number of strong-motion records that have measured ground response at large strains, any statistical analyses of seismic site-response models subject to strong ground motions are severely limited by a small number of observations. Recent earthquakes in Japan, including the M w 9.0 Tohoku earthquake of March 2011, have substantially increased the observations of strong-motion records that can be used to compare alternative site-response models at large strains and can subsequently provide insight into the accuracy and precision of site-response models. Using the Kiban-Kyoshin network (KiK-net) downhole array data in Japan, we analyze the accuracy (bias) and variability (precision) resulting from common siteresponse modeling assumptions, and we identify critical parameters that significantly contribute to the uncertainty in site-response analyses. We perform linear and equivalent-linear site-response analyses at 100 KiK-net sites using 3720 ground motions ranging in amplitude from weak to strong; 204 of these records have peak ground accelerations greater than 0:3g at the ground surface. We find that the maximum shear strain in the soil profile, the observed peak ground acceleration at the ground surface, and the predominant spectral period of the surface ground motion are the best predictors of where the evaluated models become inaccurate and/or imprecise. The peak shear strains beyond which linear analyses become inaccurate in predicting surface pseudospectral accelerations (PSA; presumably as a result of nonlinear soil behavior) are a function of vibration period and are between 0.01% and 0.1% for periods < 0:5 s. Equivalent-linear analyses become inaccurate at peak strains of ∼0:4% over this range of periods. We find that, for the sites and ground motions considered, site-response residuals at spectral periods > 0:5 s do not display noticeable effects of nonlinear soil behavior.

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“…Synthetic examples in one and two dimensions can be found in Askan et al (2007), Askan & Bielak (2008) and Burstedde & Ghattas (2009). Synthetic examples in one and two dimensions can be found in Askan et al (2007), Askan & Bielak (2008) and Burstedde & Ghattas (2009).…”

Section: Regularisationmentioning

confidence: 99%

Full Seismic Waveform Modelling and Inversion

Fichtner¹

2011

Advances in Geophysical and Environmental Mechanics and Mathematics

371

349

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The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: deblik, BerlinPrinted on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To my family and Carolin ForewordOur planet is permanently vibrating, excited by oceans, atmosphere, earthquakes, or man-made sources. Luckily, Earth's physical properties are such that these vibrations -elastic waves to be more specific -often propagate to large distances carrying information on the medium they encounter along the way. The problem of making an educated guess at the subsurface structure from observations of ground motions is as old as instrumental seismology itself (so not that old, maybe a century or so). Let us call the problem seismic tomography akin to CT scanning in medicine, a field seismologists have always envied. Because of limitations in illuminating the Earth with sufficient coverage we have never obtained the sharp and detailed internal structures so familiar from medical imaging.Up to now we have mostly cut corners in the way we model and fit our seismic data. We typically reduce long, wiggly seismograms to a few bytes of information (e.g. travel times, phase velocities) and try to explain these data with approximate theories. This has been for a good reason. Our computers were simply not fast and big enough to allow the calculation of complete wave fields through 3D Earth structures. Frequently the data just do not warrant the use of sophisticated physics.The situation regarding computational power in connection with 3D wave propagation has dramatically changed in the past few years. Even on a global scale the calculation of wave fields across the complete observed frequency range is in sight. On smaller scales (continents, basins, volcanoes, reservoirs) we are already witnessing the emergence of 3D wave propagation as the tool for data modelling, inversion and parameter studies.This was Albert Tarantola's (and others) dream 25 years ago: just simulate the physics correctly and let the data (i.e. the misfit to a theoretical seismogram) decide whether the Earth model is good or not. In his world (the probabilistic approach) this should be done using a Monte Carlo-type approach: calculate zillions of models and use all the results to estimate parameters and uncertainties. Unfortunately, we are not there yet. We still need to resort to linearisations around (hopefully good) starting models and employ adjoint-type techniques to update our Earth models. Fortunately, in many situations, good starting models can be found, making iterative waveform inversion the preferred tool to improve our Earth models using most or all of the observed data. vii viii ForewordThe book in your hands is the first to provide a broad overview on how to solve the forward problem to calculate accurate seismograms in 3D Earth m...

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Full Waveform Inversion for Seismic Velocity and Anelastic Losses in Heterogeneous Structures

Cited by 71 publications

References 61 publications

Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes

Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes

Critical Parameters Affecting Bias and Variability in Site-Response Analyses Using KiK-net Downhole Array Data

Full Seismic Waveform Modelling and Inversion

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