Sensitivity analysis of near-source ground motions to pseudo-dynamic source models derived with 1-point and 2-point statistics of earthquake source parameters

Abstract

Ground motion prediction is an important element in seismic hazard analysis. However, the availability of recorded strong ground motion data is limited, particularly for large events in near-source regions. Recently, several physics-based ground motion simulation approaches have been developed, which may be useful for understanding the effect of earthquake source on near-source ground motion characteristics. In this study, we investigated the sensitivity of near-source ground motions to finite earthquake source processes with pseudo-dynamic source models, based on 1-point and 2-point statistics of earthquake source parameters. We simulated ground motions for Mw 6.6 and 7.0 vertical strike-slip events using pseudo-dynamic source models derived from multiple sets of input source statistics and investigated the characteristics of near-source ground motions relative to the input source statistics, focusing on the relative station locations with respect to finite-fault geometry. Our results show that the effect of earthquake source on near-source ground motions can vary depending on the locations of near-source stations. The variability of ground motion intensities derived from multiple sets of input source statistics was greater in the forward directivity region. This pattern is also consistent for pseudo-spectral accelerations with various periods. The pseudo-dynamic source modeling method with 1-point and 2-point statistics seems to be an efficient framework for understanding the effect of earthquake source on near-source ground motion characteristics.