The earthquake hypocenter relocation using double difference method in West Borneo NPP potential site

Seismic hazard analysis was one of the Potential Nuclear Power Plant site feasibility study aspects to assess the safety level from earthquake hazards. For this analysis, an accurate earthquake hypocenter is crucial to determine the earthquake source zone. Hypocenter relocation analysis with The Double Difference method was conducted to enhance the earthquake position to its corresponding source for the earthquake in the 1000 km radius from the Potential Nuclear Power Plant site. The relocation process was divided into two segments, Java and Sumatra segments. The results showed that the relocated hypocenter distribution tends to have similar general distribution with the pre relocated event. The relocated hypocenter result showed a better separation between earthquakes cluster from shallow active fault and the subduction zone. The subduction zone was better delineated after the relocation. The hypocenters depth cross-section plot for both Sumatra and Java segments shows a better cluster solution that corresponds to the Sumatra and Java subduction zones and the shallow active fault such as Enggano thrust, Sumatra strike-slip fault, Opak fault, and Garsela fault.