APLIKASI METODE GAYABERAT GRADIEN VERTIKAL UNTUK IDENTIFIKASI KOMPAKSI SEDIMEN PADA CEKUNGAN

• Main Author: Sayoga, Varian
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69885
• Institution: Institut Teknologi Bandung

The cities in Bandung Basin had been growing rapidly in population and developing infrastructure. This phenomenon caused potential disasters such as land subsidence, building damage, difficulty in obtaining groundwater, and flood expansion. This land subsidence is caused by sediment compaction due to excessive groundwater extraction in the aquifer zone and an increased infrastructure load on the surface. To delineate compaction sediment in the area study we use vertical gradient gravity. The vertical gradient gravity is a variation of gravity measurements carried out at one point with different heights to increase shallow anomaly response. We conducted vertical gravity gradient at the Bandung Basin for 100 station points. Positive anomalies in the vertical gradient gravity with increased density values indicate sedimentary compaction corelated with subsidence of land and groundwater caused by infrastructure development on the surface and excessive groundwater extraction. To understand subsurface conditions, we conducted forward modeling for residual and vertical gradient gravity anomaly simultaneously in 2 interest lines at Kosambi’s formation. From forward modeling, we discover higher density layers at about 200 m from surface likely as top breccia from Beser’s formation with contrast density value +0.15 gr/cc. Besides that, we found compaction sediment has variation depth from about 50 m to 100 m, with contrast density value +0.1 gr/cc.