Abstract: Crustal deformation is one of the important evidences for seismic and geological hazard assessment. The lack of comprehensive and reliable observations of Beijing and surrounding regions prevents us to understand these two kinds of hazards of this area. In this study, we utilize L-band InSAR deformation observations to investigate the accumulated deformation of this region in a range of 190 km×150 km within about a 3-year period. We show the detailed characteristics of the crustal deformation of Beijing area between 2007 and 2010, to help the assessment of nature hazards of this area. The results show that, the main source of deformation of Beijing area is subsidence induced by ground water extraction, and the accumulated maximum Line-Of-Sight deformation can be as large as 37.6 cm in the observation period. The strong affection of subsidence and atmospheric noise lead to the difficulties of separating active tectonic deformation from the InSAR data quantitatively, however, it is confirmed that the large scale deformation (length >50~100 km) of fault motion and active tectonics in the observation period is weak, and contributes little to the accumulated deformation. The most important point is that, the crustal deformation exhibits in a form of strip-and-block, and clearly shows the strong correlation between subsidence and active tectonics, especially for the NW-striking Nankou-Sunhe fault.

Key words: Crustal Deformation, Geological Hazard, Earthquake Hazard, L-band InSAR, Subsidence, Beijing area