Preliminary Result of Hypocenter Relocation Using Double Difference Method along Sumatran Fault, Indonesia

Abstract

The Sumatran fault zone has a high seismicity and seismic hazard threat levels due to this fracture through densely populated areas. The fault zone of Sumatera has 19 main segments which each segment has the possibility to generate a strong earthquake. Therefore, in this study we attempt to improve the accuracy of hypocenter locations which is needed as basic analysis in advance seismology and in seismic hazard analysis. The final objective of this study is to analyze the subsurface seismic velocity structure of the Sumatran fault by applying seismic tomography method. For the preliminary result, we have been conducting double-difference method to relocate 967 events recorded by 49 stations compiled by Meteorological, Climatological, and Geophysical Agency of Indonesia (MCGA) from 2009 to 2017 along Sumatran fault. Our preliminary results from the relocation proces indicate prominent features of event cluster around Sumatra fault system. The next step, we will improve the onset of P-and S-wave arrival time by using waveform cross-correlation in order to get more reliable hypocenter location.