Abstract
This study assesses probabilistic seismic hazard for Sumatra through a series of progressive approaches. In order to better illustrate possible seismic activity of each seismogenic source—shallow area source, the active fault source, the Sunda trench, and subduction intraslab area source, our analysis implements earthquake catalogs and fault parameters. For the Sumatran fault system (SFS) and the Sunda subduction interface, we assessed their rupture probabilities based on the truncated exponential model, the time-dependent Brownian Passage Time (BPT) model, and the earthquake rates considering complex multiple-segments rupture. Seismic activity of each area source was modeled through the Gutenberg-Richter law. Due to lack of ground-motion models specifically for the study region, we proposed several earthquake scenarios and compared with instrumental observations and felt report to determine appropriate ground motion models for various sources. We assessed seismic hazard considering the bedrock engineering (i.e., \(\:{V}_{s}^{30}\:=\:760\:m/s)\) and specific site condition (based on the \(\:{V}_{s}^{30}\) map by USGS). The results indicate that the region close to the SFS and the Sunda trench face higher hazard levels (1.0-2.1 \(\:g\)) in both 10% and 2% probability of exceedance in 50 years. We also assessed city-scale seismic hazard for seven metropolitans, including Lampung, Bengkulu, Bangka Belitung, Palembang, Padang, Medan, and Aceh—through hazard curves and disaggregation. The hazard disaggregation indicated that the SFS is the primary contribution to the overall seismic hazard in the regions. The outcomes of this study provide valuable information for emergency response planning, urban development, and preparedness of governmental agencies before a disastrous earthquake in the Sumatran region.