Earthquake location using a 3D velocity model : an example in Sichuan Province, China

Abstract

We investigate the benefits of applying three-dimensional velocity models to seismic event location. We develop a technique for three-dimensional seismic event location, utilizing a finite difference method for travel time calculation and a grid search method for location. We apply this technique to the location of three events in Sichuan Province, China, an area of complex deformation and scattered seismicity. The lateral differences between published event locations and those obtained using this three dimensional technique are between 6.2 and 12.8 km, suggesting that the relocation of a larger number of events may refine our understanding of deformation in this region. The locations using the three-dimensional velocity model compare favorably with locations using a one-dimensional model, returning location depths consistent with the geology of the area and showing smaller location variability when using a jackknifing technique.