Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Asad, A. M. Articles by Louie, J. N. Search for Related Content GeoRef GeoRef Citation

Inversion of travel-time data for earthquake locations and three-dimensional velocity structure in the Eureka Valley area, eastern California

Compagnie Generale de Geophysique (CGG), 16430 Park Ten Place, Houston, Texas 77084
Seismological Laboratory,, MS 174Mackay School of Mines University of Nevada, Reno, Reno, Nevada 89557

Abstract

We develop an earthquake travel-time inversion methodology suitable for determining three-dimensional velocity structure and fault-plane orientation for an area with limited a priori information. Using a cascaded combination of a nonlinear simulated annealing optimization and linearized inversion, we investigate local three-dimensional compressional velocity structure and estimate the orientation of a fault plane in the Eureka Valley area of eastern California. We inverted travel times recorded at 20 permanent and 8 portable stations from an M 6.1 mainshock and a few hundred aftershocks for P-wave velocity and hypocentral coordinates. Using the velocity model obtained by the nonlinear optimization as an initial model for linearized inversion, we relocated the hypocenters and further fine-tuned the model. The relocated hypocenters define a north-northwest-trending fault dipping steeply westward. The final crustal velocity model features a low-velocity trend along the strike of the Eureka Valley and a high-velocity block southwest of the valley. Compared with a fully linearized inversion, our scheme demonstrates independence of the final results on the initial model and the potential of avoiding local minima.