The kinematics of the Turkish-Iranian Plateau are studied using information from the focal mechanisms of earthquakes, observations of the geomorphology associated with active faulting, and published GPS measurements. Combining these sources of data makes it possible to examine how the velocity field is accommodated by active faulting. A band of previously unrecognised oblique normal faults is described, rotations about vertical axes are shown to be occurring in the northern plateau, and the age of initiation of the current configuration of faulting is estimated. The dynamics of continental deformation are then considered, in a series of studies of parts of the India-Asia collision zone. The observed surface velocities are found to be consistent with viscous flow in response to gravitational body forces, and the importance of the lower boundary condition is discussed. Deformation maps for common rock-forming minerals show modelling results to be consistent with laboratory measurements of the rheology of minerals. Gravitationally-driven flow provides an explanation for the occurrence of normal-faulting earthquakes in the southern Tibetan Plateau, and for the formation of the Eastern Himalayan Syntaxis. The final part of this thesis combines the two approaches described above. The kinematics of the southeastern margin of the Tibetan Plateau are examined in detail, and numerical modelling is used to suggest the origins of the observed velocity field. It is found that the long-wavelength deformation is driven by pressure gradients in the crust resulting from topographic slopes, and that horizontal surface velocities alone cannot be used to distinguish between two possible modes of deformation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:597987 |
| Date | January 2008 |
| Creators | Copley, A. C. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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