Effect of parameters on near-fault ground-motion simulations for moderate-strong earthquakes by stochastic finite-fault method

This paper described stochastic finite-fault method and related improvements which have been widely used in simulating acceleration time histories. The improved method is more suitable for the simulation of moderate-strong earthquakes. And then we compared the time histories and average PSA (pseudo-acceleration response spectra) of near-fault moderate-strong earthquakes for different site azimuths so as to analyze parametric sensitivity quantitatively to near-fault ground-motion simulations for moderate-strong earthquakes using the revised program. The results show that PSA values are apparenly different at short period for different site azimuths, and stress drop is the most important model parameter, which controls response spectra at short period. In addition, the geometric-spreading coefficient has a significant impact on PSA. Therefore, in order to get more accurate simulations for the near-fault moderate-strong earthquakes we should focus on stress drop and geometric-spreading coefficient which have great influence on PSA values at short period when applying stochastic finite-fault method to the seismic safety evaluation of moderate earthquakes. And the distribution of dominating site azimuths is another factor which should also be considered in this situation.