DISCRIMINATION OF THE BENER MERIAH, ACEH, INDONESIA MW 6.2 DESTRUCTIVE EARTHQUAKE AS IMPLICATION FROM NEW (RE) ACTIVE FAULT: EVIDENCES FROM GEOLOGY AND GEOPHYSICAL DATA

This study aims to show the evidences from geology and geophysical data answering the presumption of the cause of a destructive earthquake in Bener Meriah, Aceh, Indonesia Mw 6.2 in July 02, 2013. We have considered that this event was not fully associated with Aceh Segment or Tripa Segment, part of the Sumatra Fault System (SFS). We did the field survey to get geology and seismic data of the aftershocks. A result of the relocation method in seismology using Modified Joint Hypocenter Determination (MJHD) using mainshock and aftershocks data showed the mainshock Mw 6.2 is around 96.67±0.03 E and 4.67±0.02 N at depth 3.52±4.33 km. The mainshock and aftershock locations and the dip of the hypocenter distribution showed the un-possibility of the implication of Aceh Segment or Tripa Segment activity. We determined the second vertical derivative (SVD) of bouguer anomaly in the vicinity of the new (re) active fault estimation from the sattelite measurement. We identified the position and direction of the fault segment that cause this earthquake. This analysis was also supported by the ground cracking and landslide data (showed in the photography of the field survey). We successfully distinguish the Bener Meriah earthquake Mw 6.2 in Aceh, Indonesia as implication of a new (re) active fault trending northwest-southeast located in 10-20 km of Sumatra Fault System (SFS). The position of this causing segment is clearly visible. Based on the analysis of the second vertical derivative (SVD) on four slices that we made, we are considering that the type of this fault segment is strike slip.