Identifying the structure as a hot water outflow path using gravity in Jatimulyo, South Lampung

Abstract

Abstract Geothermal manifestations have been utilized as a tourist attraction (geo-tourism) worldwide. Geothermal manifestation systems could be found in many forms such as hot springs. The path of the hot water flow is controlled by the existence of geologic structures such as faults as the medium. Geophysical methods in general have been used to image and characterize subsurface layers. The gravity method using the natural source has been employed to determine the geological structure, such as faults. This study aims to identify the structure related to the outflow path which is part of the geothermal system using gravity method in Jatimulyo Village, Jati Agung, South Lampung. The result shows the contrast anomaly indicating the existence of a fault that could be a hot water path. An outflow zone which is characterized by low temperatures because it is far from heat sources. The complete Bouguer Anomaly is used to create 2D forward modelling where the model is divided in 2 layers. The first layer is indicated as Lampung Formation (QTl) with density of 1.8 g/cc, and second layer recognized as bedrock with denser rock of 2.78 g/cc representing Tertiary Paleozoic (Pzg) Gunung Kasih Complex Formation.