A. Simanjuntak1 , M. Umar2 , R. Sipayung3 , D. Sianipar4
1National Seismological Center, Meterological and Geophysical Agency
2Tsunami Disater and Mitigation Research Center
3Banjarnegara Geophysical Station of Central Java
4Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), National Seismological Center, Jakarta, Indonesia
Abstract:
We present high-resolution seismicity imaging after studying earthquakes which occurred around the Tripa fault. The Tripa fault is a segmented fault of SFZ, actively moving, characterized by a strike-slip fault and located in southern part of Aceh. We used 10 years the earthquake catalogue and continuous seismic waveform from BMKG, including P and S arrival times. We did manually picking of inspections to get arrival times and compare it with BMKG results. The earthquake hypocenters, which trapped on 10 km depth, were relocated by using inversion with double difference method based on arrival times in each station. We used 6 local velocity model, and compare each of them to get the best RMS result. From 70 events of the BMKG catalogue 50 events were manually relocated and 40 events with BMKG arrival times. With RMS <0.1, the results show a clear separation of seismicity areas into 3 cluster. Hypocenters were located deeper, more precise than before, and separated into 2 clusters on the left and right side. The strike focal direction from Global-CMT follows the distribution of hypocenters relocation. The left and right sections of clusters must be further investigated, both had generated a devastating earthquake.
