A Comparative Study of Tilt Derivative (TDR) and Second Vertical Derivative (SVD) from Gravity Data, Case Study: Umbul Niti Geothermal Field

The gravity method is a passive technique measures the response of rock or mineral's density which correspond to the gravity acceleration. In this study, we use gravity data acquired from a potential geothermal area in Umbul Niti, South Lampung. Analyzing geothermal systems involves examining components such as the heat source, reservoir, clay cap, and faults. This study places particular emphasis on the identification of subsurface faults as pathways for the recharge and discharge of geothermal systems, utilizing gravity data. One of the important steps in processing gravity data is anomaly enhancement. In this research, a comparative study of Tilt Derivative (TDR) and Second Vertical Derivative (SVD) filters was performed to infer the subsurface fault. Synthetic gravity data are needed to check the boundary of low and dense material using TDR and SVD analysis. The synthetic data show that the border of the body anomaly is located at the zero contour of the TDR and SVD map. Thus, the estimated subsurface faults were revealed from the zero contour of the TDR and SVD. The application of TDR and SVD to the gravity field data exhibits that the majority of subsurface faults trend provide Northwest - Southeast directions. Hence, the estimation of subsurface faults is indicative of the continuity of the Lampung Panjang Fault.