Evolution of upper mantle beneath East Asia and the Tibetan Plateau from P-wave tomography

The main objective of the research presented in this thesis is to improve our understanding for the evolution of the upper mantle beneath East Asia and the Tibetan Plateau through high resolution P-wave tomography. The approach to high resolution tomography is based on (i) the combined use of a large range of different types of seismic data, (ii) the use of approximate finite frequency sensitivity kernels to account for difference in measurement technique and frequency content of the data, (iii) the use of an irregular grid with cell-size adapted to sampling density, and (iv) the use of a priori information, e.g., on crustal structure from receiver function analysis. I construct a multi-scale and high resolution seismic tomography model of the upper mantle structure beneath East Asia and the Tibetan Plateau. The new model reveals that the mantle structure associated with the Indian subduction varies considerably along the strike of the collision zone. From west to east, the dip angle of Indian subduction increases and the distance over which the plate underthrusts the Tibetan Plateau decreases. Oblique subduction and changes of dip angle in the central part of the collision zone may cause and determine the location of the north-south trending normal faults in central Tibet. The eastward retreating slabs of western Pacific and Philippine plates are deflected in the transition zone beneath the Korea, Japan Sea, and East China. Some of Mesozoic subducted slabs have reached as far west as 1100E longitude under the Yangtze Craton, which might have resulted from the Eocene subduction at the South China and Japan trenches.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Li, Chang, Ph.D.

Advisor dc:contributor.advisor

• Robert D. van der Hilst.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40964

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40964