Characterization of typological rocks using the geomagnetic method for mapping geological disaster susceptibility areas in Malang Regency, Indonesia

Abstract

Based on data from the BPBD Malang Regency, more than 100 geological disasters, such as earthquakes, landslides, and subsidence, yearly with losses of up to 3 Billion IDR. Based on field observations, one of the villages that frequently experience landslides and subsidence almost every year is Srimulyo Village, Dampit District. This condition requires research on the subsurface to analyze the trigger factors for geological disasters to increase disaster mitigation and awareness. This study aims to analyze the typological characteristics of the rocks in the study area using the geomagnetic method as a geological disaster mitigation strategy. The method is geomagnetic; measurement designs regularly cover the entire study area with a distance of 300 meters between measurement points, while research is presented in 2D models and the analysis is based on the measured magnetic anomaly values on the reduce to pole (RTP) map. The results showed that the correlation between the RTP maps, regional geology, and field observations gave mutually correlated results. Based on the interpretation result of the RTP map, we create a Disaster Risk Zone map marked with the highest magnetic anomaly values in the northwest and northeast areas. The types of disasters in this zone vary, such as landslides, ground movements, and earthquake damage. The meeting between compact rock layers with sandy clay layers and faults causes rocks that were originally stable to become unstable, so the potential for disaster is large. The results of this study contribute to the local government in carrying out disaster mitigation and development planning.