The Research of GPS Monitoring of the Chuan-Dian block

We use the observational data during 1999 to 2006 of the Crustal Movement Observation Network of China (CMONC) to calculate the horizontal movement velocities in the Eurasian reference frame at CMONC 151 stations in the Chuan-Dian block and its adjacent areas.The velocity values range from 3.44 to 19.74 mm/a, and the average velocity is of the value 11.68 mm/a.Analysis of the directions of the velocities leads us to conclude that the Chuan-Dian block and its adjacent areas are in clockwise rotation centered on the eastern Himalayan node,and the Chuan-Dian block is obviously squeezed along the north-south direction,but is stretched along the east-west direction.Using least-squares fitting we obtain the collective velocity of the Chuan-Dian block as 13.36 mm/a in the direction of E 64.9° S,and those of the Northwest-Chuan subblock and Middle-Dian subblock as(15.66 mm/a,E 52.1° S)and(12.57 mm/a,E 72.4°S),respectively.