Current Crustal Strain Field in the Sichuan-Yunnan Area by Joint Inversion of GPS and Seismic Moment Tensor

By using 84 seismic moment tensors,collected from the Harvard centroid moment tensor between 1903 and 2003,and 214 GPS velocity observations,collected from the crustal motion observation network of China between 1998 and 2004,we fix the weight scaling factor of these two kinds of data in the joint inversion through Helmert method of variance components estimation(VCE),and invert for current crustal motion in Sichuan-Yunnan area.Meanwhile,on the basis of the analysis of inverted results,the following views are concluded.① By using VCE,the weight scaling factor of GPS observations with a value of 0.833 is higher than that of seismic data,with a value of 0.167.It shows the importance of GPS observations with high accuracy and relatively uniform distribution in joint inversion.② The crustal strain field in Sichuan-Yunnan area shows that the direction of compression strain is EW in the areas above 30°N and below 30°N,NE in the west of 100°E,and NW in the east of 100°E,which is accordance with other studies.