Spatial Analysis of Social Vulnerability to Earthquake Hazard in Bengkulu City

Abstract

As a province on Sumatera's west coast, Bengkulu is prone to earthquakes. The region lies on the meeting of the Indo-Australian Plate, the Eurasian Plate, and the Sumatra Fault. Additionally, it is affected by the Mentawai Fault. Various attempts were made to reduce the impact of an earthquake, for instance, by identifying the region's vulnerability. Variables used in this study were based on Social Vulnerability Index (SOVI) by Susan L. Cutter, such as the number of people working in the informal sector and the population density to determine exposure. Other variables in the index include the proportions of vulnerable age population, impermanent houses to determine sensitivity, wealthy households, high school graduates and above, and social capital to determine adaptive capacity. This research aimed to map the vulnerability of the region. It followed social indicators connected to the Peak Ground Acceleration of ≥ 5.0 RS earthquake in 2000-2015. The overlay approach and scoring were used to conduct this village-based study. If the regions were farther from the city center, vulnerability levels tended to be lower; the south is an exception. The research also found an interesting pattern of vulnerability levels to earthquakes. The vulnerability level in the high PGA region was high and very high when the magnitude ranged between 5.0 and 5.9 RS. Meanwhile, the region's vulnerability was high and very high in the low PGA region if the magnitude reached 6.0 to 7.9 RS.