Investigating the characteristics of near-source ground motions using pseudo dynamic source models derived with 1-point and 2-point statistics of earthquake source parameters

Ground motion prediction is an important element in seismic hazard analysis. However, the availability of recorded strong ground motion data is limited, in particular, in near-source regions. Recently, several physics-based ground motion simulation approaches have been developed and they may be useful to understand the effect of earthquake source on near-source ground motion characteristics. Song et al. (2014) developed a pseudo-dynamic source modeling method, based on 1-point and 2-point statistics of earthquake source parameters. They demonstrated that the effect of the earthquake source process on near-source ground motions can be investigated efficiently in the framework of 1-point and 2-point statistics. In this study we aim to investigate the detailed characteristics of near-source ground motions controlled by finite source process, utilizing the pseudo-dynamic source modeling framework. For instance, the difference of the source effects between forward and backward directivity regions. We simulated ground motions for a Mw 6.5 strike-slip event, using pseudo-dynamic source models derived from multiple sets of input source statistics, and investigated the detailed patterns of near-source ground motions, depending on the input source statistics. Our preliminary results show that the effect of earthquake source on near-source ground motions can vary depending on both azimuth and source-to-site distance. The variability of ground motion intensities derived from the multiple sets of input source statistics is more dominant in the forward directivity region and at the shorter source-to-site distance. The pseudo-dynamic source modeling method with 1-point and 2-point statistics seems to be an efficient framework to understand the earthquake source on near-source ground motion characteristics systematically. We plan to simulate ground motions for larger events (Mw 7.0) and investigate the magnitude dependency of the near-source ground motion characteristics.