Active source zones and earthquake vulnerability around Sumatra subduction zone

Accurate identification of locations of earthquake clusters is critical for seismic risk and vulnerability estimation. About 19,500 earthquakes with magnitude >2.5 and depths <400 km were analysed to identify the most active seismic segments along the Sumatra subduction zone. The b -values appear to vary significantly spatially. A total of 16 clusters, each with more than 40 earthquakes that have been identified are distributed asymmetrically, and in-homogenously along the length of the subduction zone. Such inhomogeneous spatial distribution of earthquake clusters may be due to the segmentation of the Sumatran Fault caused by oblique convergence at varying rates. Furthermore, we evaluate vulnerability in the region by integrating two multi-criteria decision models, i.e., the analytical hierarchy process (AHP) and weighted aggregated sum product assessment (WASPAS) methods. We find that about 18.63–32.12% of the region is under moderate to high risk due to secondary effects of earthquakes, and about 49.25% of the region is a relatively low vulnerability. Our work may provide valuable insights to researchers and the hazard mitigation agencies working in the region by enabling them useful insights.