Groundwater play in extensional regime: a case study in Cibunar Region, Garut, Indonesia

Abstract

The intermountain Cibunar area of the Garut basin periodically suffered from a drought and thus became a devastating hazard. Its fault structure as an impact of the extensional regime might affect the groundwater play as a transport or barrier system. The tectonic setting and its disruption of volcanic lithologies by faults make the area's hydrogeology very complex. The conducted electrical resistivity tomography coupled with gravity and magneto-telluric studies revealed the aquifer play on the zone is affected by the extensional regime. Tectonically, the drought Cibunar district is close to the top of the horst structure where the uplifted segments might contribute to the limited low resistivity aquifer zone and triggered the flow to the graben zone. The low and high resistivity on the region was related to an unconfined aquifer and unsaturated zone, while the medium zone remains unclear.