SENSITIVITY ANALYSIS OF B-VALUE AND SLIP-RATE TO PSHA MODELING IN EARTHQUAKE MITIGATION EFFORTS IN BENGKULU PROVINCE AND SURROUNDINGS

• Main Author: Meidina Azwar, Chintya
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57754
• Institution: Institut Teknologi Bandung

Bengkulu Province is one of the areas in Indonesia that is prone to earthquake hazards. The area is located near the Sumatran fault zone and subduction zone which causes Bengkulu and its surroundings to often feel earthquake shaking. The purpose of this study to analyze the sensitivity of b-value and slip-rate in probabilistic seismic hazard analysis (PSHA) modeling. There are three earthquake source mechanisms that are used, namely the mechanism of the fault earthquake source, background earthquake source and subduction (megathrust) earthquake source. Background earthquake data that can be used are 1,158 data that have been filtered for mainshocks. The data was collected from 1964–2020 with the ISC-EHB and BMKG catalogs. The source data for the fault and subduction (megathrust) earthquakes used are from the National earthquake catalog which contains 29 fault segments and seven subduction segments. USGS PSHA will be used as one of the software to perform data processing in this study. The b-value and slip-rate used will affect the value of the maximum acceleration produced and the recurrence of the earthquake. To determine the sensitivity of the b-value used three ranges of b-values, namely 0.726; 1; and 1.274. The results show that for all earthquake sources from processing of three b-value ranges, the Peak Ground Acceleration (PGA) value is 1.2–1.5 g. Meanwhile, the slip-rate also uses three ranges of values, namely the slip-rate (normal) value from the National earthquake catalog, with the addition of the slip-rate value (+0.5 mm/yr) and (+1 mm/yr). The results of the slip-rate obtained PGA values of 1.2–1.5 g. Based on the results of the study, it can be concluded that the b-value and slip-rate used are relatively sensitive to the PGA value in areas close to the earthquake source in Bengkulu Province and its surroundings.