FOCAL MECHANISM ANALYSIS OF SHALLOW EARTHQUAKE IN 2010-2018 AT CENTRAL ACEH

• Main Author: Kurniawan, Dofi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42186
• Institution: Institut Teknologi Bandung

The Sumatran Fault System is an active fault that extends over 1900 km from Banda Aceh to Semangko Bay. This Sumatran Fault System consists of 19 segments that are not continuous. Beside the Sumatra Fault System, there are several secondary faults including the Batee segment and the Pantan Terong segment in the Central Aceh region. On 2 July 2013 there was an earthquake with Mw 6.1 due to the activity of Pantan Terong segment. In this research focal mechanism analysis was carried out on several earthquake events in the Central Aceh region to identify the characteristics of active faults in this area. This study used shallow earthquake waveform data with a depth <50 km and magnitude > 3. The earthquake waveform used is in the range 2010 to 2018 from the GFZ and ISC Catalog via IRIS through webDC3 at BMKG. The initial process is manual picking of arrival time P and S waves. Then the initial hypocenter location was determined by the Geiger method. The initial hypocenter position was relocated using a double-difference method with a combination of catalog data and waveform cross-correlation, then focal mechanism was determined by moment tensor inversion. The results of the hypocenter relocation of the earthquakes in the period 2010 to 2018 succeeded in identifying three fault segments in the study area, namely the Central Aceh, Batee, and Pantan Terong segments. Focal mechanisms solution on the three fault segments studied showed the dextral strike-slip movement with the northwestsoutheast strike and relatively vertical dip. In this research also found an indication of the flower structure formed by Pantan Terong and Samalangga segments at Lampahan