Local stress and seismic activity at West Sumatra

Abstract

The Earthquakes that occured in West Sumatra was dominated by a trust mechanism. This is due to the westren part of Sumatra stretching the subduction zone parallel to the sumatran coastline and fault movement. The size of the earthquake energy release can depend on local stress conditions and the levelof seismic activity. Local tectonic stress conditions were determined using seismotectonic parameters, whereas the distribution of seismic activity levels used eartquake magitude frequnecy relationships. Based on this analyisis, local stress conditions for each segment in West Sumatra are categorized in a high level. The segment with the highest stress conditions is in the Suliti and Sumani Segment, the medium stress conditions in in the Sianok dan Suliti segment, and the lowest is the Mentawai segment. The level if seismicity in the segment of West Sumatra based on seismotectonic parameters is categorized as low seismic level. The segment with the lowest seismic level are Sumani and Suliti, followed by Sianok and Sumpur, the highest level is the Mentawai segment.