Analisis Coulomb Stress Change pada Gempa Kepulauan Tanimbar 2023 dan Kaitannya terhadap Distribusi Gempa Susulan

Abstract

This study evaluates the spatial distribution of aftershocks in the Tanimbar Islands, Indonesia, using the Coulomb Stress Change (CSC) approach following the 2023 mainshock. The region is located within an active tectonic zone resulting from the interaction of the Indo-Australian, Eurasian, and Pacific Plates, making it highly susceptible to moderate-to-large earthquakes. CSC analysis was applied to assess stress changes that influence the potential occurrence of aftershocks by examining two different faulting models. Aftershock data were collected and spatially mapped to identify the relationship between the mainshock and the distribution of subsequent seismic events. The results indicate a significant correlation between areas experiencing increased Coulomb stress and the frequency of aftershocks. Red-colored areas represent regions with positive Coulomb stress changes, indicating stress increases, whereas blue-colored areas represent regions with negative Coulomb stress changes, indicating stress decreases. The findings from both CSC methods demonstrate that the CSC approach is effective in predicting potential post-earthquake seismic activity. The resulting Coulomb stress distribution maps provide important contributions to earthquake disaster risk mitigation in the Tanimbar Islands and other similar tectonically active regions.