Geological Mapping Optimisation Using Satellite Gravity, Satellite Imagery, and Seismic Shear Velocity (Vs30) to Monitor Lithological Condition in Geothermal Area of Mount Salak, West Java

¹ Department of Geomatics Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
² Department of Geophysics Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
³ Department of Informatics, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia

¹ Corresponding author: widya@geofisika.its.ac.id

Abstract

Conventional geological mapping has several challenges such as limitation of area coverage, tough terrain, unstable weather condition, high-cost survey, also limitation of expert geologist that capable to do geological mapping. Remote sensing is an alternative solution to geological mapping through the combination of satellite gravity, satellite imagery, and seismic shear wave velocity. This research aims to optimise geological mapping activity in the Mount Salak geothermal area from ineffective area coverage mapping and inefficient budgeting allocation. Integration of rock density from satellite gravity, lithological distribution from satellite imagery, and seismic shear wave velocity from Vs30 are giving more detailed lithological units interpretation with specific physical conditions. There are two main area of Mount Salak that should be preserved geothermal resource sustainable. Northeast area needs to preserve heat source and groundwater recharge area, that consist of dense vegetation as landcover, relatively high rock density value (2.30 - 2.50 gr/cm³), high seismic shear wave velocity (600 – 900 m/s), also dominantly covers by Andesitic-Basaltic Lava. Southwest area preserve reservoir and caprock of geothermal conceptual model, where covers by dense vegetation with several bare land as geothermal wells and powerplants, relatively low rock density value (2.00 – 2.20 gr/cm³), moderate seismic shear wave velocity value (450-750 m/s), also dominated by several pyroclastic product such as Lapilli and Tuff. This research shows good indication in geothermal resource preservation in the Mount Salak, that keep natural aspect of geothermal conceptual model still preserved well.