Analysis of peak ground acceleration (PGA) using the probabilistic seismic hazard analysis (PSHA) method for Bengkulu earthquake of 1900 – 2017 period

Abstract

This study was aimed to find out and analyze Peak Ground Acceleration (PGA) in order to mitigate the earthquake. The PGA map resulted was an acceleration map on bedrock with a probability exceeding 10% and 2% with the Probabilistic Seismic Hazard Analysis (PSHA) method for PGA in 50 years. The software used to analyze the Probabilistic Seismic Hazard Analysis (PSHA) method is USGS-PSHA. The data used was in the form of historical earthquake data from 1900 to 2017 and a depth of 1 km to 300 km. Earthquake magnitude ≥ 4.5 Mw with a research limit of 2.53° - 7.58° SL and 96.1° - 106.1° EL from the International Seismological Center (ISC) earthquake catalog, ISC-EHB Bulletin, United States Geological Survey (USGS) and The Geophysical Climatology Meteorology Institution (BMKG), a radius of 500 km from the border of Bengkulu Province. The results show that the most earthquakes for shallow depths with a magnitude of 4.5 Mw - 5.9 Mw as much as 2805 times, while for medium depths at magnitude 4.5 Mw - 5.9 Mw as much as 642 times. The probabilistic calculations exceeding 10% are 0.24 gal - 0.86 gal and probabilistic calculation exceeding 2% is 0.36 gal - 1.35 gal. The areas exposed to the danger zone are Lebong, Rejang Lebong, Kepahiang, Mukomuko, North Bengkulu and Bengkulu City. Whereas the regions included in the medium zone are Seluma and Bengkulu Tengah. And the areas of the safe zone are Kaur and South Bengkulu.