Abstract: Based on the formula deduced by Aleksandrowski for calculating pitch direction of fault slip data, an improved method for determination of tectonic stress tensor was put forward. A method for back analysis of tectonic stress field was deduced by least square method based on the relation between tectonic stress with pitch direction of fault slip data in different stress ratio values. At last, the calculating process was deduced by Matlab program. The fault slip data were obtained in the Wushan mining region, Jiangxi province. On this basis, by the improved method of inversion of fault slip data, the parameters of tectonic stress tensor in mine region were determined. The tectonic stress field in this area since Late Jurassic was obtained, by comparing the faults with the average stress field of the region obtained from focal mechanism solutions and studying distribution of the strike-slip faults and the tectonic setting of this area. It is indicated that the tectonic stress field in this area has better stability since Late Jurassic. The progress of solving tectonic stress tensor and the application of the improved method show that, comparing with the graphical instrument method put forward by Aleksandrowski and the method for back analysis by Etchecopar, the method is simple and more feasible, and the focal mechanism solution is reasonable.

Key words: fault slip data, pitch direction, back analysis, Wushan copper mine region, tectonic stress tensor