Abstract

For the research of the stress state of southeast Tibet Plateau, from 2013 to 2015, the Institute of Crustal Dynamics organized some of in-suit tests by hydraulic fracturing method in the mountains along the side of Yarlung Zangbo River. The tests plan has been executed at 7 positions in the mountains, and some more will be organized in short future. Before these tests, there is no detail stress measurement data cover this area. The tests data showed the ground stresses in the mountains along the sides of Yarlung Zangbo River were relatively higher than in other areas in China. At the depth of about 500m under the mountain surfaces, the major principal stress mostly distributed in an interval from 15MPa to 20MPa, at the depth of about 800m, the interval rises to 23MPa to 28MPa, that could be considered to be 2MPa-5MPa higher than other areas of china. All of the major principal stresses were more or less directing from south to north, distributed in an interval from N21°W to N1JDE. A preliminary analysis had given out a common consideration about these test data that the higher stresses values in this area is reasonable for the reason of the powerfully squeezing of Indian plate, the same as the orientations.

Introduction

Tibet is Earth's largest and highest plateau, with a flat interior and many mountains (Fig. 1). How such topography formed and maintained has profound implications on the mechanics of continental deformation (Paul Tanponnier et al., 2001). Within the framework of India's collision with Asia, it is meaningful to research the today's stresses inside the mountains.

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