Full Anelastic Waveform Tomography Including Model Uncertainty

2008-12-01
This article is concerned with the problem of seismic inversion in the presence of model uncertainty. In a recent article (Askan et al., 2007), we described an inverse adjoint anelastic wave propagation algorithm for determining the crustal velocity and attenuation properties of basins in earthquake-prone regions. We formulated the tomography problem as a constrained optimization problem where the constraints are the partial and the ordinary differential equations that govern the anelastic wave propagation from the source to the receivers. We employed a wave propagation model in which the intrinsic energy-dissipating nature of the soil medium was modeled by a set of standard linear solids. Assuming no information was initially available on the target shear-wave velocity distribution, we employed a homogeneous shear-wave velocity profile as the initial guess. In practice, some information is usually available. The purpose of the present article is to modify our nonlinear inversion method to start from an initial velocity model, and include a priori information regarding the initial model parameters in the misfit (objective) function. To represent model uncertainties, given an initial velocity model, in addition to the data misfit term in our objective function, we include an L(2)-normed weighting term, which quantifies the model estimation errors, independently of the measured data. We use total variation (TV) regularization to overcome ill posedness. We illustrate the methodology with pseudo-observed data from two-dimensional sedimentary models of the San Fernando Valley, using a source model with an antiplane slip function.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA

Suggestions

Full waveform inversion for seismic velocity and anelastic losses in heterogeneous structures
Askan Gündoğan, Ayşegül; Bielak, Jacobo; Ghattas, Omar (Seismological Society of America (SSA), 2007-12-01)
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 prob...
AN ANALYSIS TO IMPROVE STABILITY OF DRIVE-MODE OSCILLATIONS IN CAPACITIVE VIBRATORY MEMS GYROSCOPES
Alper, S. E.; Sahin, K.; Akın, Tayfun (2009-01-29)
This paper presents an analysis showing that it is possible to determine the factors that limit the stability of drive-mode oscillations of a vibratory MEMS gyroscope with precise modeling. Specifically, unwanted electrical resonance characteristics of the gyroscope drive-mode are analyzed together with analytical expressions, whereas the results of the theoretical analyses are verified both by simulations and measurements, which agree very well. It is demonstrated that the stability of the drive-mode oscil...
Three dimensional hyperbolic grid generation
Dinçgez, Umut Can; Aksel, Mehmet Haluk; Department of Mechanical Engineering (2006)
This thesis analyzes procedure of generation of hyperbolic grids formulated by two constraints, which specify grid orthogonality and cell volume. The procedure was applied on a wide range of geometries and high quality two and three dimensional hyperbolic grids were generated by using grid control and smoothing procedures, which supply grid clustering in all directions and prevent grid deformation (grid shock), respectively.
Overlapping Lattice Simulation of Concrete Gravity Dam Collapse Simulations
SOYSAL, BERAT FEYZA; Aydın, Beyazıt Bestami; Tuncay, Kağan; Arıcı, Yalın; Binici, Barış (2017-09-01)
Estimating the collapse limit state of concrete gravity dams within the framework of performance based design is challenging due to the uncertainty in modelling the response of these systems and the strong dependence of the behavior on the ground motion. The purpose of the study is to investigate the seismic expected damage levels by using the overlapping lattice modeling (OLM) approach with incremental dynamic analysis (IDA) for two representative dam monoliths. OLM employs pin connected bar elements exten...
Discrete element based analyses of structure-reservoir problem for gravity dams
Soysal Albostan, Berat Feyza; Arıcı, Yalın; Department of Civil Engineering (2021-1-25)
The prediction of the nonlinear behavior of gravity dams under seismic actions is challenging. Firstly, a clear damage indicator to quantify the performance limits of such structures is limited. Besides, a proper numerical model producing reliable results both in the linear and nonlinear ranges for the dam body has to be established, coupled with its surrounding reservoir. This study is focused on damage assessment of gravity dams with the goal of determining seismic and post-seismic behavior considering cr...
Citation Formats
A. Askan Gündoğan, “Full Anelastic Waveform Tomography Including Model Uncertainty,” BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA, pp. 2975–2989, 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33265.