Scenario Seismic Hazard Analysis (SSHA) in Cilegon City for post-major earthquake 2019 and 2022 infrastructure construction development

Abstract

The major earthquake events on August 2, 2019, and January 14, 2022, which devastated Banten City, gave an earthquake warning to the surrounding area, including Cilegon City. As an area with several vital infrastructures, such as Merak Port, chemical factories, steel industries, and power plants, Cilegon City requires a seismic study that can provide information for the planning and retrofitting of building structures. In this study, an earthquake analysis will be carried out using the Scenario Seismic Hazard Analysis (SSHA) for Cilegon City to calculate the bedrock acceleration. The earthquake sources modelled include the source of the Semangko Graben, Cimandiri and the Sunda Strait Megathrust Segment. This study provides several conclusions, included (1) results of seismic analysis using SSHA produced a maximum PGA value 0.05 - 0.1 g, 0.00 - 0.05 g and 0.3 - 0.4 g, for the Semangko Graben, Cimandiri and the Sunda Strait Megathrust Segment sources respectively. So, Cilegon City's infrastructure layout system must be located designed in the area with a minimum ground acceleration. The existing buildings also need to be re-analyzed based on the earthquake hazard map.