Analysis of seismicity level and return period of bengkulu area earthquake from 1960-2017

Abstract

In this research, seismicity and the return period of earthquake in Bengkulu and surrounding areas has been analyzed using the relationship between the frequency and the magnitude of earthquakes. Study area is at coordinate points of 1,1-6,4 SL and 99,5 - 104,9 EL, whereas the earthquake data used is limited only to 5.0 SR magnitude and 100 km depth from 1960-2017 sourced catalog data from United States Geological Survey (USGS) and using the Zmap Matlab 2007Rb software program. The analysis results that spatial variation b-value is 0,6-2, a-value is 5-15 while magnitude of Completeness is 5,1. And return period of earthquake with magnitude 5 ranges from 0,2-0,5 years, magnitude 5,5 ranges from 1,5-3,5 2-4 years, magnitude 6 ranges from 6-12 years, magnitude 6,5 ranges from15-25 years and magnitude 7 ranges from 10-20 years, magnitude 7,5 ranges from 30-50 years, and magnitude 8 and 8,5 ranges from 100-150 years. Hence the results show that Bengkulu area is an area with high stress level and relatives high magnitude level.