Magnetotellurics (MT) and Gravity Study of a Possible Active Fault in Southern Garut, West Java, Indonesia

In recent years, dozen low-intensity earthquakes occurred in southern Garut, West Java Indonesia; two of them were reported destructive. However, those shallow earthquake clusters are hardly associated with well-known active faults the area. Hence, we conducted 3D gravity combined 2D magnetotellurics (MT) inversions to study subsurface. Gravity and MT modeling confirm a basin around 5 km depth consisting subbasins separated by NE-SW trending local-high ridge. The local high coincides magmatic intrusion geothermal fields aligns series volcanic bodies’ lineament observed on surface. We interpret this structural as preexisting fault that serves magma pathway tectonomagmatic interaction. Shallow low-magnitude seismicity Garut area tends occur resistive bodies. heat from cooling may decrease effective fault-normal stress rocks, leading failure resistance initiate rupture. resistivity structure initial rupture affect whether or not nucleation will end up large-magnitude earthquake. Furthermore, unconsolidated young cover could amplify ground shaking when occurs might lead more extensive damage.