Present‐Time Crustal Deformation in China and its Surrounding Regions by GPS

Applying recent 10‐year GPS measurement data from some nationwide GPS networks, several regional GPS monitoring networks and the Asia‐Pacific Regional Geodetic Project (APRGP), this paper gives out a combined, consistent and unified velocity field solution in ITRF97 by rotation transformation of regional GPS network results. In order to study the characteristics of present‐time intra‐plate crustal deformation of China, we have constructed a new present‐time plate motion model named ITRF97VEL. The model can better describe present‐time features of global plate motion than the geological model NNR‐NUVEL1A. Based on the present time plate motion model ITRF97VEL, deformation velocities of more than 260 GPS sites are determined. The results show the crustal motion in China is especially inhomogeneous. The crustal deformation in the west of China is far stronger and more complicated than that in the east of China taking the N‐S seismic belt of China as a boundary. The deformation velocity gradually reduces from south to north in the west of China by energy release in several W‐E direction arc suture zones. The Qinghai‐Xizang Plateau is shortening in north‐south direction and extending in west‐east direction due to the strong shove of Indian plate.The shortening of about 15mm/a and 9–13mm/a is accommodated across Hymalayan block and the west Tian Shan respectively. Within southern Tibet,between the longitudes of 80°E to 91°E,there is E‐W extension of 20.2±1:2 mm/a. The slip rates of KJFZ in south Tibet and Altyn Tagh fault are 2–3mm/a and 4–6 mm/a respectively. Our GPS results indicate there is a less than 7mm/a shortening within the Longmen Shan. These results support the supposition of crustal thickening.