Analysis of the b-value and Seismic Deformation in the North of China

The accuracy of b-value is limited by the uncertainty of the magnitude. In order to improve the accuracy of the b-value, a statistic methodology was used to estimate the number of events based on that there are several magnitude values for one historical event by several methods to estimate the magnitude. The b-value and seismic strain rates were calculated for the three regions in the North of China. The method proved to be valid for all the regions, especially for the data with large fluctuation. In order to study the stress state, the strain rate tensor and the principal axes of tension and compression were calculated for each of three regions by the data of the focal mechanism, finally the stress state in each region was discussed.