Full waveform inversion for seismic velocity and anelastic losses in heterogeneous structures

Askan Gündoğan, Ayşegül
Bielak, Jacobo
Ghattas, Omar
We present a least-squares optimization method for solving the nonlinear full waveform inverse problem of determining the crustal velocity and intrinsic attenuation properties of sedimentary valleys in earthquake-prone regions. Given a known earthquake source and a set of seismograms generated by the source, the inverse problem is to reconstruct the anelastic properties of a heterogeneous medium with possibly discontinuous wave velocities. The inverse problem is formulated as a constrained optimization problem, where the constraints are the partial and ordinary differential equations governing the anelastic wave propagation from the source to the receivers in the time domain. This leads to a variational formulation in terms of the material model plus the state variables and their adjoints. We employ a wave propagation model in which the intrinsic energy-dissipating nature of the soil medium is modeled by a set of standard linear solids. The least-squares optimization approach to inverse wave propagation presents the well-known difficulties of ill posedness and multiple minima. To overcome ill posedness, we include a total variation regularization functional in the objective function, which annihilates highly oscillatory material property components while preserving discontinuities in the medium. To treat multiple minima, we use a multilevel algorithm that solves a sequence of subproblems on increasingly finer grids with increasingly higher frequency source components to remain within the basin of attraction of the global minimum. We illustrate the methodology with high-resolution inversions for two-dimensional sedimentary models of the San Fernando Valley, under SH-wave excitation. We perform inversions for both the seismic velocity and the intrinsic attenuation using synthetic waveforms at the observer locations as pseudoobserved data.


Time domain Gauss-Newton seismic waveform inversion in elastic media
Sheen, Dong-Hoon; Tuncay, Kağan; Baag, Chang-Eob; Ortoleva, Peter J. (Oxford University Press (OUP), 2006-12-01)
We present a seismic waveform inversion methodology based on the Gauss-Newton method from pre-stack seismic data. The inversion employs a staggered-grid finite difference solution of the 2-D elastic wave equation in the time domain, allowing accurate simulation of all possible waves in elastic media. The partial derivatives for the Gauss-Newton method are obtained from the differential equation of the wave equation in terms of model parameters. The resulting wave equation and virtual sources from the recipr...
A Nonlinear Site-Amplification Model for the Next Pan-European Ground-Motion Prediction Equations
Sandikkaya, M. Abdullah; Akkar, Dede Sinan; Bard, Pierre-Yves (Seismological Society of America (SSA), 2013-02-01)
A site-amplification model for shallow crustal regions that considers both linear and nonlinear soil effects is proposed. The original functional form of the model was developed by Walling et al. (2008) (WAS08) using stochastic simulations and site-response analysis. The major difference between the proposed model and WAS08 is that our site-amplification expression is entirely based on empirical data. To comply with this objective, a database with the most recent V-S30 information from the pan-European regi...
Estimating tectonic history through basin simulation-enhanced seismic inversion: geoinfomatics for sedimentary basins
Tandon, K; Tuncay, Kağan; Hubbard, K; Comer, J; Ortoleva, P (Oxford University Press (OUP), 2004-01-01)
A data assimilation approach is demonstrated whereby seismic inversion is both automated and enhanced using a comprehensive numerical sedimentary basin simulator to study the physics and chemistry of sedimentary basin processes in response to geothermal gradient in much greater detail than previously attempted. The approach not only reduces costs by integrating the basin analysis and seismic inversion activities to understand the sedimentary basin evolution with respect to geodynamic parameters- but the tec...
Evaluation of Site Response with Alternative Methods: A Case Study for Engineering Implications
Sisman, Fatma Nurten; Askan Gündoğan, Ayşegül; Asten, Michael (Springer Science and Business Media LLC, 2018-01-01)
In this paper, efficiency of alternative geophysical techniques for site response is evaluated in two sedimentary basins on the North Anatolian Fault Zone. For this purpose, fundamental frequencies of soils and corresponding amplitudes obtained from empirical horizontal-to-vertical spectral ratio curves from microtremors, weak motions and strong motions are compared with results from one-dimensional theoretical transfer functions. Theoretical transfer functions are computed using S-wave velocity profiles de...
Sensitivity Study of Hydrodynamic Parameters During Numerical Simulations of Tsunami Inundation
Ozer, Ceren; Yalçıner, Ahmet Cevdet (Springer Science and Business Media LLC, 2011-11-01)
This paper describes the analysis of a parameter, "hydrodynamic demand,'' which can be used to represent the potential for tsunami drag force related damage to structures along coastlines. It is derived from the ratio of drag force to hydrostatic force caused by a tsunami on the structure. It varies according to the instantaneous values of the current velocities and flow depths during a tsunami inundation. To examine the effects of a tsunami in the present study, the analyses were performed using the tsunam...
Citation Formats
A. Askan Gündoğan, J. Bielak, and O. Ghattas, “Full waveform inversion for seismic velocity and anelastic losses in heterogeneous structures,” BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA, pp. 1990–2008, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40638.