Probabilistic Seismic Hazard Analysis for Sulawesi-Maluku Region of Indonesia Using the Space–Time Epidemic-Type Aftershock Sequence Model

Sulawesi and Maluku are the only regions in Indonesia where three major plates (Eurasian, Indo-Australian and Pacific) meet, resulting in the most seismically active region in Indonesia. It is important to perform probabilistic seismic hazard analysis to understand the seismic activity in this region, study aftershock sequences, and provide comprehensive seismic hazard maps. In this study, we consider spatiotemporal analysis and perform space–time epidemic-type aftershock sequencing (space–time ETAS) to model earthquake catalog data in Sulawesi-Maluku, Indonesia. The method combines Davidon-Fletcher-Powell (DFP) algorithm and stochastic declustering algorithm. We conclude that the model has good performance and can be used to construct seismic hazard maps based on the generated model. The results of the seismic map provide information on the total rate of earthquake events occurring around the Maluku Sea, with the clustering of earthquake events spread almost throughout Sulawesi and Maluku.