Modeling 3‐D wave propagation and finite slip for the 1998 Balleny Islands earthquake

Abstract

We simulate surface waves in a 3‐D Earth model using a spectral element method for existing kinematic source models of the MW 8.1, 25 March 1998 Balleny Islands earthquake. The 3‐D model incorporates lateral variations in the crust and mantle on the basis of models Crust2.0 and S20RTS. Our objective is to investigate the fit of the observed and simulated long‐period surface waves in the hope of improving on the existing source models. We modify a body wave model determined by Henry et al. (2000) to improve the fit of long‐period surface waveforms. We demonstrate that adding a smooth component of slip extending over a fault that connects the two subevents determined by Henry et al. (2000), without invoking slip on multiple fault planes or on unconnected fault patches, provides reasonable fits to long‐period surface waves as well as body waves.