Seismic hazard disaggregation analysis of West Kalimantan NPP potential site: A precursory study

A precursory study in seismic hazard disaggregation analysis of West Kalimantan NPP (Nuclear Power Plant) potential site has been performed. Based on the previous study, Bengkayang regency in West Kalimantan Province has been chosen as one of the potential NPP sites. Although the area is regarded as a low seismicity region, seismic hazard analysis remains an obligatory task to be performed based on BAPETEN’s Chairman Regulation No. 8 of 2013 [1]. The objective of this study is to present preliminary seismic hazard analysis and take a closer detail to disaggregation analysis of the studied area. Disaggregation analysis was conducted at a single point selected site in Bengkayang regency based on secondary geological and seismological regional data using OpenQuake software. The probability of ground motion exceedance corresponds to 10 % in 50 years is set as the seismic hazard level. The seismic source model within the radius of 1,000 km comprises of twenty-one sources is presented here using the combination of zonation and zone-less approach. Probabilistic seismic hazard analysis (PSHA) is performed to estimate the mean hazard spectra and mean probability of ground motion exceedance at any given spectral acceleration at the site. For the chosen location, a peak ground acceleration (PGA) of 0.15 g has resulted. Meanwhile, the disaggregation analysis resulted in a dominant earthquake magnitude of 5.75 Mw and source-to-site rupture distance of 25 and 65 km.