Supriyadi, V.A. Fadilah, Khumaedi, Sunarno, A.N. Hikmah
East Java is one of the provinces on Java Island characterized by relatively high seismicity, making it highly susceptible to earthquake hazards. This vulnerability is further exacerbated by the region′s high population density, which increases the potential for significant losses of property and even human lives in the event of a disaster. Therefore, earthquake disaster mitigation efforts aimed at reducing seismic risk are paramount. One such attempt involves mapping the spatial distribution of earthquake risk levels across East Java. In this study, the assessment of earthquake risk levels is based on three key factors: hazard, vulnerability, and capacity. The hazard factor is represented by Peak Ground Acceleration (PGA); the vulnerability factor is indicated by population density; and the capacity (or resilience) factor is measured using the Human Development Index (HDI). PGA values were calculated using the empirical Donovan method based on earthquake catalog data from the United States Geological Survey (USGS) for 1973-2023 with a magnitude ≥5. Each factor was standardized using the Davidson model and overlaid using a scoring technique. In contrast, the weighting of each factor was conducted using the Analytical Hierarchy Process (AHP) method as developed by Firmansyah et al. (2009). The mapping was carried out with the aid of ArcGIS software. Based on the PGA calculations, values in East Java range from 13.114 gal to 90.306 gal, corresponding to intensity levels of I to VII on the Modified Mercalli Intensity (MMI) scale. The resulting earthquake risk index values range from 1.00 to 4.30. Using Sturges′ rule, the risk values were classified into three categories: low, medium, and high risk. The resulting risk distribution map shows that 14 regencies/municipalities (44.74%) fall into the low-risk category with a total area of 27,815.824 km2; 14 regencies/municipalities (36.84%) fall into the medium-risk category with an area of 19,593.694 km2; and seven regencies/municipalities (18.42%) are categorized as high-risk with a total area of 643.174 km2. © Published under licence by IOP Publishing Ltd.
Physics Department, Universitas Negeri Semarang, Semarang, Indonesia
