Utilization of satellite gravity data to modeling the sub-surface structures of Mount Lamongan and surroundings

The Lamongan Mountain Area has a unique geological feature that has 61 Cindercone and 29 Ranu / Maar and has three craters at its mountain top, i.e. Tjupu, Tarup and Lemongan. Research using Topex satellite gravity data was conducted to study the subsurface structure of Mount Lamongan and its surroundings, related to mapping the density contrast under Mount Lamongan to the surrounding mountains (G. Bromo-Tengger-Semeru, and G. Iyang-Argopuro). The first step is to correct the Topex satellite gravity data, i.e. Bouguer and terrain correction to obtain Complete Bouguer Gravity Anomaly (ABL) data. From the ABL data, the inversion process is then performed using Grav3D software released by the University of British Columbia, to obtain a three-dimensional contrast model of sub-surface density. From the inversion processes shown that inversion there is a lower density contrast around G Lamongan. Low-density contrast pattern to the east of G. Lamongan is thought to be a fault. This fault is believed to be a fault that controls the occurrence of Tiris geothermal manifestations.