Detecting Land Subsidence Using Gravity Method in Jakarta and Bandung Area, Indonesia

Since the declining of groundwater level often causes the land subsidence, it is important to monitor both height changes and gravity changes. The rate of gravity changes versus height changes depends on the density of the material. Thus it gives important information about the mechanism of the land subsidence. The objective of research is to monitoring the land subsidence by gravity observations. Establishing a new method to monitor the environmental issues such as groundwater variation, land subsidence, by means of absolute gravity measurements, a field type absolute gravity meter, Micro-G LaCoste Inc. A10 have been conducted in Jakarta and Bandung area, not only to confirm the accuracy of the instrument but also to investigate the practical and efficient measurement methods for the field surveys. The results present that the gravity value increases in the coastal in Jakarta. Otherwise the biggest gravity change was detected around Lembang fault in Bandung area.