State of stress and its bearing on tectonics under the Tibetan Plateau

Abstract

Abstract Using the composite plot of pressure and tension axes of the available focal mechanism solutions of earthquakes, this paper investigates the nature and process of stress systems and their impression on tectonics under the Tibetan Plateau. A composite plot shows that the Tibetan Plateau is now experiencing a NNE-SSW-directed compressive stress with an almost ESE-WNW tensile stress, and it confirms a wrench movement towards the east along a prominent strike-slip fault. Transcurrent tectonics appear to be the principal phase of deformation in Tibet in response to the northward push of India. This study also suggests that the extensional tectonics of the Tibetan Plateau primarily involve a combination of compressive and shear stresses as a consequence of continued continental convergence, rather than merely a gravitational body force.