The 4D gravity or time lapse gravity has been used many reseracher to identify fluid injection in oil reservoir. The objective of this study is to find the better way in interpreting 4D gravity anomaly due to fluid injection around the reservoir. Radial Derivatives are derivative values of gravity anomalies against horizontal distances in the radial direction. Radial inversion is a two-dimensional inversion of lines with radial directions resulting in a 3-dimension model. Time lapse microgravity research have been performed in "X Oil Field" with amount of 604 data point covering area of 4000 m x 5000 m. This Radial derivative and Radial inversion have been aplied at an injection well of the X oil field. The yield show that 4D gravity anomaly value due to injection is 0.02 mGal to 0.36 mGal. Radial derivative value in the area is 0 micro Gal/cm to 0,012 mGal/meter. Radial inversion shows radius of fluid front movement is 304 meters to 1120 meters. Radial derivative and Radial inversion have been proven fairly good to identify injected fluid movement in the reservoir.

Flash flood led to high levels of water in the urban areas, causing many problems such as bridge collapse, building damage and the victim died. It is impossible to avoid risks of floods or prevent their occurrence, however, it is plausible to work on the reduction of their effects and to reduce the losses which they may cause. The objective of this paper is to generate a flash flood map in Suoh region, using satellite images, UAVs images and GIS tools. Analytical Hierarchical Process is used to determine the relative impact weight of flood causative factors to get a composite Flood Hazard Index (FHI). The causative factors in this study are flow accumulation (F), rainfall intensity (I), geology (G), land use (U), slope (S), and elevation (E). The presented methodology has been applied to an area in Suoh region, where recurring flood events have appeared. Initially, FIGUSE method resulted in an FHI and a corresponding flood map. A sensitivity analysis on the parameter’s values revealed some interesting information on the relative importance of each criterion, presented and commented in the discussion section.

Gravity research in the Rajabasa geothermal prospect area was conducted to determine geothermalreservoirs and faults as reservoir boundaries. The research includes spectrum analysis and separation of the Bouguer anomaly to obtain a residual Bouguer anomaly, gradient analysis using the second vertical derivative (SVD) technique to identify fault structures or lithological contact, and 3D inversion modeling of the residual Bouguer anomaly to obtain a 3D density distribution subsurface model. Analysis was performed based on all results with supplementary data from geology, geochemistry, micro-earthquake (MEQ) epicenter distribution map, and magnetotelluric (MT) inversion profiles. The study found 3 (three) geothermal reservoirs in Mount Balirang, west of Mount Rajabasa, and south of Pangkul Hot Spring, with a depth of around 1,000-1,500 m from the ground level. Fault structures and lithologies separate the three reservoirs. The location of the reservoir in the Balirang mountain area corresponds to the model data from MEQ, temperature, and magnetotelluric resistivity data. The heat source of the geothermal system is under Mount Rajabasa, which is indicated by the presence of high-density values (might be frozen residual magma), high-temperature values, and the high number of micro-earthquakes epicenters below the peak of Mount Rajabasa.

Desa wisata Pagar Jaya memiliki beberapa obyek geowisata yang sangat menarik untuk dikunjungi seperti: Dinding Dasit, Pantai T. Indah, Pantai T. Hantu, dan Batu Wayang. Semua obyek geowisata tersebut berada di area pesisir dan sangat rentan terhadap ancaman bencana tsunami. Nilai penting dari proses partisipatif dalam kajian risiko bencana adalah  mewadahi masyarakat dalam mengambil keputusan dan merumuskan tindakan prioritas pengurangan risiko bencana. Tujuan dari pengabdian ini adalah: memetakan kondisi eksisting obyek geowisata Dinding Dasit, Teluk Indah, Teluk Hantu, dan Batu Wayang berbasis geospasial, mengedukasi masyarakat akan prinsip-prinsip mitigasi bencana tsunami, dan mengintegrasikan data geospasial dan nonspasial dari kelompok masyarakat dalam pembuatan jalur evakuasi bencana tsunami di Desa Wisata Pagar Jaya. Kelompok masyarakat yang tergabung dalam Kelompok Sadar Wisata (Pokdarwis) Desa Wisata Pagar Jaya merupakan subjek utama dalam proses pemetaan partisipatif. Proses pemetaan melalui tahap Focus Group Discussion dan in-depth interview berkaitan dengan risiko bencana dan jalur evakuasi. Sistem Informasi Geografis kemudian mentransformasikan hasil pemetaan partsipatif dalam bentuk digital. Hasil dari penelitian ini adalah peta partisipatif jalur evakuasi untuk bencana tsunami di Desa Pagar Jaya yang secara geografis berada di pesisir selatan Pulau Sumatera.

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