Land Subsidence in Bandung Basin and its Possible Caused Factors

Bandung basin which located in West Java, Indonesia is a large intra-montane basin surrounded by volcanic highlands. The basin is a highly urbanized area whose population has been rapidly increasing since few decades ago. It is widely believed that the increase of population, as well as industrial activities, will increase the degree of groundwater extraction and will eventually lead to land subsidence over the area of Bandung basin. According to results of ten champaign of GPS (Global Positioning System) surveys, which were conducted within the period of 2000 to 2012 it was found that several locations in Bandung basin experienced land subsidence, with an average subsidence rate of about –8 cm/year and it can reach to about –16.9 cm/year in a certain location and time period. The large subsidences occur in Cimahi, Gedebage, Dayeuhkolot, Rancaekek, Majalaya, and Katapang districts. Similar results are also achieved from InSAR (Interferometry Synthetic Aperture Radar) data. During the period of 1999 to 2010, maximum rate of land subsidence in the Bandung basin reached 2 meters that occurred in industrial areas such as in Cimahi, Katapang, Dayeuhkolot, Gedebage, and Rancaekek. It is indicated that there is a strong correlation between the land subsidence and groundwater extraction in Cimahi, Dayeuhkolot, Majalaya, and Rancaekek. Furthermore, there could also be possible existence of other causes due to natural compaction in almost all subsidence areas and tectonic processes in Dayeuhkolot, Gedebage, Cimahi, dan Majalaya.