Jakarta is the capital city of Indonesia with a population of about 12 million people, inhabiting an area of about 625 km 2 . It is well known that several areas in Jakarta are subsiding rapidly. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil and tectonic subsidence. In addition to the leveling method, Global Positioning System (GPS) survey methods have been used to study land subsidence in Jakarta. In this paper, we characterize subsidence in the Jakarta basin using eight episodic/campaign GPS surveys between 1997 and 2005. The estimated subsidence rates are 1-10 cm/year. The observed subsidence rates in several locations show a positive correlation with known abstraction volumes of groundwater extraction. These basin-wide series of GPS measurements show how this type of measurement can play an important role in multiple public policy decision making in this rapidly growing area.

The Bandung Basin is a large intramontane basin surrounded by volcanic highlands, in western Java, Indonesia, inhabited by more than five million people. Based on the results of five GPS surveys conducted in

No abstract

Abstract. Bromo is an active type-A volcano located inside Tengger caldera in Eastshow that the deformation of Bromo volcano is typically in order of a few cm, with the inflation and deflation processes before and after the eruption. Estimated location of the pressure source is found to be beneath the active crater with depth of about 1 km below the caldera floor.

No abstract