PSI analyses of land subsidence due to economic development near the city of Hangzhou, China

In this work we mapped the spatial and temporal patterns of the land subsidence near the city of Hangzhou, China by PSI analysis with 49 scenes of ERS-1/2 SAR images acquired from 1992 to 2006 to detect and retrieve the subsidence due to economic development. The main reason of land subsidence in Hangzhou is groundwater exploitation, which is necessary for the rapid economic development, especially in China. Xiaoshan Economic and Technological Development Zone was approved as a state-level development zone by the State Council in May, 1993. Since then the zone has been suffering land subsidence. There have been more than 300 overseas-funded enterprises with investors from 26 countries and regions by the year 2006. The development of this area can be divided into three periods according to its pace: construction period (1993-1996), stable increase period (1996-2001) and high-speed period (2001-2006).