THE PRELIMINARY RESULTS OF MEASURING THE CRUSTAL DEFORMATION IN QINGHAI-TIBET AREA USING GPS TECHNIQUE

Shanghai Observatory, Chinese Academy of Science, 80 Nandan Road, Shanghai 200030, P.R.China

GPS repetition measurement data in Qinghai-Tibet area in 1992 and 1994 have been processed using SHAnghai observatory Gps Analysis Program (SHAGAP). Based on the preliminary results given in this paper, several conclusion can be arrived:

1.

At present, the relative accuracy of measuring baseline is better than 10ppb, and near 1ppb using GPS technique, it is possible to obtain a reliable information about large scale crustal horizontal motion from the periodic repetition measurements for no long time.

2.

It is first time to get the reliable result of large scale crustal movement in China. These results are also the first time to give the direct observed evidence to support the opinion that the main force source to effect the motion of chinese continental crust is from the northward propulsion of India plate. From the results, it also gives the evidence to maintain the conclusion that the effect of the propulsion to crustal motion of Qinghai-Tibet area is reduced from south to north.

3.

The result shows that the diamond block surrounded by the fracture from Jingsha river to Hong river and other fractures from south to north in southwest area of China , has an obvious southward strike slip movement, that coincides with the motion model which comes from the geological or geophysical data.