Preliminary Investigation of the Relationship Between Gravity Anomalies and Seismic Hazard along Lembang Fault

Abstract The Lembang fault, a significant geological feature in the Greater Bandung agglomeration area, is one of the main active faults on the island of Java, Indonesia. A historical low-magnitude earthquake of M3.3 in 2011 just above the Lembang Fault in the Muril village caused damage to hundreds of houses. This study explores the relationship between seismic hazard and subsurface structures using published gravity data integrated with the V S30 global mosaic map to provide a comprehensive analysis of the seismic hazard implications along the Lembang Fault. Our preliminary study sheds light on unique features of gravity anomaly heterogeneity characteristics along The Lembang Fault. While we did not find a simple and specific correlation between the Bouguer anomaly pattern and the Lembang fault surface trace, we did discover an intriguing correlation between the Bouguer anomaly and local seismicity around the Lembang fault. Most recorded seismic events are concentrated in the western parts of the Lembang fault, where the Bouguer anomaly is low. The eastern part, on the other hand, exhibits a high gravity anomaly with fewer seismic events. The low Bouguer anomaly, which can be interpreted as thick sediment, is a key factor in our research. It is closely associated with the potential for ground amplification due to earthquakes, a significant aspect that our research aims to understand and mitigate for practical applications.