A Monte Carlo simulation approach to Aftershock Probabilistic Seismic Hazard Analysis (APSHA): methodology and verification

Aftershock probabilistic seismic hazard analysis (APSHA) is an essential element of rescue plan and reoccupying the buildings after large earthquakes. APSHA is usually performed by parametric approaches in which the seismic source causing the mainshock should be accurately identified. As an alternative solution, current study attempts to implement Monte Carlo simulations in APSHA. The main advantage of the proposed APSHA approach is that it does not require identifying the geometry of the causative seismic source. To this end, synthetic aftershock catalogs were generated for three major aftershock sequences occurred in western Zagros in Iran. The catalogs were then employed to predict Peak Ground Acceleration (PGA) values due to the aftershocks and the results were verified against recorded PGA data. The results of APSHA were generally consistent with the recorded PGA data according to different validation methodologies. However, the accuracy of the results obviously depended on the exceedance probability as well as the time interval elapsed from the mainshock.