ABSTRACT
At present, various stress measurement methods have been developed and abundant in-situ stress data are accumulated. Many scholars conducted comprehensive researches concerning regional stress using in-situ stress data. Jing Feng et al. analyzed crustal shallow stress distribution in Chinese Mainland. Zhao Dean et al. studied the pattern of in-situ stress distribution in China. Xie Furen et al. investigated the regional characteristics of ground stress of the mainland of China. Chen Qingxuan et al. discussed the feature of contemporary crustal stress in terms of both lateral distribution and vertical variation. Zeng Qiusheng et al. studied the basic characteristic of crustal stress state in China using the results from in-situ stress measurement. Zhu Huanchun andTao Zhenyu summarized the features of maximal and minimal horizontal stress variation with depth in the world. Brown obtained the ratio of vertical and horizontal average stress to vertical in-situ stress and its variation with depth. Mary Lou Zoback et al. published the World Stress Map. However, detailed researches with regard to the statistical characteristics of stress variation with depth in Tibetan Plateau and its tectonic stress feature are rare. This paper analyzes the statistical features of the horizontal maximal and minimal stress variation with depth in Tibetan Plateau, and investigates the magnitude and orientation of tectonic stress in each of its subregions. The results show that the tectonic stresses gradually become stabilized beneath ∼100
meters depth, and each tectonic division exhibits distinctive tectonic stress values and orientations. In the following we first clarify the two concepts – maximal and minimal horizontal stress and tectonic stress – used in this paper.
