The geophysical surveys are needed to obtain information on subsurface geology for infrastructure development, mitigation of landslide and geothermal. Cilaki drainage basin is an area Garut Regency at southern part of West Java. The area has complex geological and the main target in development plan of Southern part of West Java. The electrical resistivity method of the Schlumberger configuration was used to identify the geological subsurface and the active fault of the study area. The measurement of the electrical resistivity was made on 7 lanes (GL 1 until GL 7). The location has a height of 195 to 925 meters above sea level with depth reaching more than 120 meters and electrical resistivity value of 6-450 Ω meters. Generally, the electrical resistivity value of Quaternary rock units have value between 80 and 450 Ω meters and Tertiary rock unit have value of 6-40 Ω meters. Based on the results of data analysis can be interpreted that the area has been deformed. This is reflected also in the geomorphology as an indication of tectonic phenomenon in the form of active faults. Quantitatively, this is reflected in the value of the mountain-front sinuosity (Smf) index which ranges 1.036 to 2.173. This phenomenon occurs in geomorphology which is composed of Tertiary and Quaternary rocks.

The Java Island is an active volcanic arc that experiences several volcanism episodes, which gradually changes from South to North from the Late Oligocene to Pleistocene, following the subduction of the Australian plates underneath the Eurasian plates. During the Eocene, the southern and northern part of Java was connected as one passive margin system with the sediment supply mainly comes from Sundaland in the north.  The compressional tectonics creates a flexural margin and a deep depression in the central axis of Java Island and acts as an ultimate deep-sea depocenter in the Neogene period. In contrast to the neighboring Northwest and Northeast Java Basins in the Northern edges of Java Island, the basin configuration in the East-West trending depression in median ranges of Java (from Bogor to Kendeng Troughs) are visually undetected by seismic due to the immense Quaternary volcanic eruption covers.Five focused window areas are selected for this study. A total of 1,893 Km sections, 584 rock samples, 1569 gravity and magnetic data, and 29 geochemical samples (rocks, oil, and gas samples) were acquired during the study. Geological fieldwork was focused on the stratigraphic unit composition and the observable features of deformation products from the outcrops. Due to the Paleogene deposit exposure scarcity in the Central-East Java area, the rock samples were also collected from the mud volcano ejected materials in the Sangiran Dome.The distinct subsurface configuration differences between Bogor and Kendeng Troughs are mainly in the tectonic basement involvement and the effect of the shortening on the formerly rift basin. Both Bogor and Kendeng Troughs are active petroleum systems that generate type II /III Kerogen typical of reduction zone organic material derived from transition to the shallow marine environment. The result suggests that these basins are secular from the neighboring basins with a native petroleum system specific to the palaeogeographical condition during the Paleogene to Neogene periods where the North Java systems (e.g., Northwest and Northeast Java Basin) was characterized by oxidized terrigenous type III Kerogen.

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Research area is located in Bayah District, Lebak Regency, Banten Province. The research location is located approximately 80 kilometers southwest of Jakarta. This area has a complex geological structure, as well as found many intrusive and metamorphic rocks. In this research area, geothermal manifestations were found in the form of four hot springs (APPC-1, APPC-2, APPC-3, and APC) as well as two cold springs (ADC-1 and ADC-2). This study aims to identify the relationship of geological structure control with the occurence of manifestations in the research area, as well as to determine the Bayah non-volcanic geothermal prospects. The method used is Fault and Fracture Density analysis for structural analysis of research area and magnetic map analysis for interpretation of geothermal prospect prospect. Structural analysis methods performed in the form of lineament delineation, determination of lineament density and major trends, and application of structural sequence model. The results of structural analysis will be correlated with the occurences of geothermal manifestations with the aim of identifying the most influential structural patterns as the pathway for geothermal fluid to reach surface in the study area. Magnetic data is also used to determine the possibility of Bayah non-volcanic geothermal prospects. The developing structure in the research area has NE-SW and NW-SE directions. The FFD analysis shows that high-density lineament is located in the southeast of research area where 3 hot springs manifestation APPC-1, APPC-2, APPC-3 are present. This manifestation appears in the lineament with NE-SW direction. Magnetic data also obtained negative magnetic anomalies in the southeast of the study area. It can be concluded that the lineaments with NE-SW direction influence the fluid outflow the most, and Bayah non-volcanic geothermal prospect areas are located around APPC manifestations.

The Ciletuh-Jampang area is located in the western tip of the Southern Mountain of West Java, Indonesia. The area is presently well publicized in an effort to bring the unique geological characteristics exposed in this particular place to become the Global Geopark Network (GGN) of UNESCO. Ciletuh area exhibits a rare mega-aphitheater morphology. Stratigraphically West Java composed of clastic sediments of continental and volcanic island arc origin with the interruption of sub-aerial volcanic rocks and the coastal reefs banks developed along the coasts both in the north and the south. The age of the rock ranges between Eocene to Recent. The analysis of regional structure shows that a set of deep seated faults was recognized dominating the area in NNW-SSE and NNE-SSW directions. The released faulting occurred in E-W direction. The low angle shallow upthrustings facing north of skin structure in E-W direction dominate the upper part of the rock sequence. The structural analysis revealed the continuous prevailing stress field in SSW-NNE direction since Eocene time. The advancing landslides are readily observable in the rim of the amphitheater of Ciletuh. This phenomenon seems to demonstrate the initial stage (primarumpf) of the geomorphologic cycle taking into account the flat surface of Jampang area in the surroundings. Further investigations revealed the geomorphologic evidences of the formation of plateau, namely the erosion surface, old terraces, mountain tables, old beach ridges and the characteristics of drainage pattern. Two remnants of main plateau were recognized in Ciletuh-Jampang area, namely Bentang Plateau and Jampang Plateau. Further investigations show that at least five locations of plateau were identified in western part of Java Island, namely Dieng Plateau (+ 2,000 m), Pengalengan Plateau (+1,300 m), Bentang Plateau (+ 1,000 m), Jongrangan Plateau (+ 850 m) and Jampang Plateau (+ 700 m). A rough estimation reveals the annual rate of lifting in Java Island since Pliocene time ranges most likely between 5.0 and 5.4cm.