Abstract

This study aims to map earthquake-prone areas based on the soil site classes associated with a Vs30 value in the South Bengkulu, Indonesia. A microtremor measurement was performed. The microtremor data obtained is in the form of an H/V curve that is matched to the model curve, so that a shear wave velocity profile is obtained. From the shear wave velocity profile at a certain depth, the value of Vs30 is obtained at each study location. The results of the study show that the distribution of Vs30 values in the South Bengkulu region, Indonesia consists of two soil site classes, namely site class C and site class B. Site class C (SC) consists of very dense soil and soft rock, while site class B (SB) consists of rock. The SC soil site class is distributed in a southwest-northeast direction and the SB soil site class is more dominant in a southeast�northwest direction. Based on the class of the soil site, this area is considered a relatively safe area from the threat of an earthquake. However, it should be noted for the lower shear wave velocity values at several study locations.

Key Points

• The study identifies Vs30 values and their relationship with soil site classes.
• Two soil site classes, C and B, represent varying densities of soil and rock.
• Microtremor data were analyzed using H/V curves to derive shear wave velocity profiles.
• Despite some lower shear wave velocities noted, this area is generally seen as safe from earthquakes.