Adi Susilo, Siti Zulaikah, Ahmad Fauzi, Ilham, Ma'muri, Ken Wirawan, Saffanatul Haniyyah, Ahmad Zarkoni, Yoga Dharma Persada, Andy Anderson Bery, Muhammad Fathur Rouf Hasan
Based on Indonesia's active fault map, this study focuses on the Eurasian and Indo-Australian plate subduction zone in the southern sea of Java, an area that is highly susceptible to earthquake risk and soil vulnerability. This study aims to determine soil vulnerability based on average shear wave velocity of the top 30 m (Vs30) and sediment thickness (z1.0) parameters to map areas at risk of earthquake in the study area. From both parameters, the most vulnerable and safest area in Purwodadi Village, Indoensia will be determined. The method used in this research is microtremor measurement with a portable miniature broad band (MBB-2) seismograph. Measurements were conducted at 19 points spaced approximately 500 m apart. Horizontal vertical spectral ratio (HVSR) inversion was applied to obtain shear wave velocity profiles at each point. Soil assessment was performed using Vs30 parameters, classified according to the American society of civil engineers (ASCE) standards. The results show that areas with relatively high earthquake vulnerability, indicated by low Vs30 values, are located near measurement points RKI08 and RKI18 in residential areas and RKI04 on slopes with Vs30 values are 219.0 m/s, 248.9 m/s, and 230.2 m/s respectively. Besides that, these points have high z1.0 value, these values are 388.0 m, 517.8 m, and 46.6 m respectively. Meanwhile, areas with lower vulnerability are found at RKI10 and RKI09 in residential areas and RKI05 on slopes, with Vs30 values are 502.0 m/s, 481.1 m/s, and 416.0 m/s respectively. These points have Vs30 values classified as “very dense soil” and have low z1.0 values (60.3 m, 109.6 m, and 43.9 m respectively). Based on data processing, there is a fault that stretches straight from RKI04, RKI11, to RKI14. However, more research needs to be conducted using alternate methods to confirm the existence of the fault. This mapping is expected to provide local authorities valuable input for disaster mitigation planning. © 2025 The Authors
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Brawijaya, Malang, 65145, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang, 65145, Indonesia; Department of Physics, Faculty of Mathematical and Natural Science, Universitas Negeri Padang, Padang, 25171, Indonesia; Meteorological, Climatological, and Geophysical Agency Malang, Malang, 65165, Indonesia; Environmental Science, Universitas Brawijaya, Malang, 65145, Indonesia; Meteorological, Climatological, and Geophysical Agency, Jakarta, 10610, Indonesia; Earth System Processes and Hazard Modeling Center, Geophysics Programme, School of Physics, Universiti Sains Malaysia, Penang, 11800, Malaysia; Universitas Brawijaya, Malang, 65145, Indonesia; Center Study on Geosciences and Hazard Mitigation, Universitas Brawijaya, Malang, 65145, Indonesia
