(Special session) Resource exploration and big-data processing

[2K0201-07-03] [Student presentation: Doctoral course] 3D inversion analysis of gravity data for clarifying geologic structural control on the high-temperature Telaga geothermal system, Indonesia

○Angga Bakti Pratama¹, Katsuaki Koike¹ (1. Kyoto University)

Chairperson : Taiki Kubo (Kyoto University)

Keywords:density distribution, gravity enhancement, inversion analysis, permeability, heat source

Clarifying the Talaga geothermal system, a high-temperature field indicated by marvelous fumaroles and hot springs, is a critical issue in understanding geological and geothermal structures controlling on the high temperature. To cope with this issue, the gravity data were analyzed and interpreted to determine the structure that controlled the fluid-flow system from the viewpoint of the rock density distribution. Separation of the regional and residual gravity data was also performed with additional derivative anomaly enhancement to derive local, significant features, followed by overlying the surface manifestations and geologic structures with the separation and enhancement results. A noteworthy feature detected is that a complex anomaly contrast is correlated with the appearance of the surface manifestations in the middle study area, which suggests high permeability. The northeastern part shows a correlation of anomaly contrast with the rim structures bounded by the geothermal system. Furthermore, 2D and 3D inversions of the gravity data were conducted to confirm the distribution of subsurface anomaly. The result detected more clearly the zones with high permeability that probably correspond to the reservoir and a heat source in the middle to southern part of the Talaga Geothermal Field.