An analysis of Coulomb stress change and triggering interaction toward seismic activities in the area West Sumatera within January 2000-June 2018

Abstract

The West Sumatra region is one of the areas prone to earthquake disasters caused by 3 factors. First, namely the Subduction Zone, which is the meeting of two large tectonic plates of the Indian Ocean Plate subducting below the L200 plate of the Eurasian Continent. Second, the existence of the Mentawai Fault which is a horizontal fault due to the sloping subduction process around the Mentawai Islands. Third, the existence of the Sumatran Fault that occurs due to the existence of the Indo-Australian plate which crashes into the western part of the island of Sumatra tilted, resulting in pressure. This study aims to analyze the coulomb displacement of stress and trigger interactions on seismic activity in the West Sumatra region from January 2000 to June 2018 using earthquake data from the United States Geological Survey (USGS) catalog sourced from Global Centroid Tensor Moment Catalog (CMT) earthquake data, United States Geological Survey Catalog (USGS), International Seismological Center Catalog (ISC), ISC-EHB and Meteorology and Geophysics Agency (BMKG), covering the boundaries of -4° SL- 1°NL and 96° - 104°EL. With earthquake magnitude (Mw) ≥7 SR and depth of 1 to 500 km for calculation of Coulomb Stress. Whereas for seismicity later with magnitude Mw ≥ 3.0 up to 9.0 depths of 1 to 500 km Based on analysis of the earthquake on September 12th, 2007 Mw = 8.5 is a trigger earthquake that triggered all significant earthquakes Mw ≥7 SR, earthquake on September 13th, 2007 Mw = 7.9 is a trigger earthquake that triggered the earthquake that occurred on September 13th, 2007 Mw = 7.0 and February 25th, 2008 Mw = 7.2, the earthquake of February 25th, 2008 and September 30, 2009 was a category of non-trigger earthquakes while the earthquake was significant October 25th, 2010, distribution of stress changes Positive Coulomb is more dominant compared to the negative Coulomb voltage change distribution. This means that after a large earthquake occurred on October 25th, 2010, the Mentawai segment area still has a high accumulation of stress.