Volcanic Geohazard Analysis - Case Study from the Ujung Lemah Abang Nuclear Power Plant Area, Central West Java

Abstract

The paper discusses the proposed development plan of a nuclear power plant in the Ujung Lemah Abang (ULA) region, located in the northern part of Mount Muria in Central Java, Indonesia. The study evaluates the potential volcanic disasters at the proposed site of the Ujung Lemah Abang nuclear power plant (NPP-ULA) near Mount Muria using the Bayesian method, which is based on a probabilistic model of the spatial distribution of volcanic events in the past and the geological processes model.Mount Mulia is a polygenetic volcano that undergoes periodic eruptions alternating between lateral and central eruption-dominated phases. Semivariogram analysis shows a range of 150,000 years. This corresponds to the average duration of volcanic activity and the time between eruptions. Mount Muria volcanic complex can be classified as an extinct volcano with limited future eruption potential based on its last activity 320,000 years ago. The probability of eruption occurrences in Muria within the next 100 years is 1.21856 x 10−5. With this probability of eruptions, it appears that the Muria Mtn is not going to be erupted anytime soon. However, when a new magma system emerges, resulting in epicenter concentrations beneath Mount Muria, micro-earthquake monitoring is required to detect magmatic activities beneath the Muria Volcanic Complex. To estimate the likelihood of phreatomagmatic eruptions, geothermometer monitoring in deep wells is required as an active monitoring of hydrothermal activity in the Muria Volcanic Complex.