Hazard Consistent Aftershock Ground Motion Intensity Map and Arrival Time Sampling for Regional Seismic Risk Analysis

This repository contains the code and data generated for the paper "Hazard Consistent Aftershock Ground Motion Intensity Map and Arrival Time Sampling for Regional Seismic Risk Analysis" which is submitted to Earthquake Spectra.

In the paper, we present a method for selecting aftershock scenarios, ground motion intensity maps, and arrival times for regional seismic risk analysis. A workflow for regional aftershock probabilistic seismic hazard analysis (APSHA) is employed, where the full aftershock catalog is generated using an earthquake rupture forecasting model and the modified Epidemic-Type Aftershock Sequence (ETAS) model. The full aftershock catalog, consisting of both rupture scenarios and arrival times, may contain hundreds of thousands of aftershock scenarios, making seismic risk analysis computationally prohibitive. The proposed method selects a subset of aftershock rupture scenarios and samples ground motion intensity maps and arrival times that are consistent with the seismic hazard estimated from the full aftershock catalog. This approach minimizes the difference between the aftershock seismic hazard at various time points, as calculated using the sampled maps and arrival times, and that derived from the complete aftershock catalog. The method is demonstrated through a case study in Northern California. Results show that the proposed method effectively samples aftershock ground motion maps and arrival times that are consistent with the complete aftershock catalog, which enables efficient evaluation of the seismic risk for spatially distributed infrastructure systems under aftershock effects.