Chuang Xu^a, Ziwei Liu^b, Zhicai Luo^a, Yihao Wu^a, Haihong Wang^c
a MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, No. 1037 Luo Yu Road, Wuhan 430074, People’s Republic of China
b Institute of Seismology, Chinese Earthquake Administration, No.48 Hong Shan Ce Road, Wuhan 430071, People’s Republic of China
c School of Geodesy and Geomatics, Wuhan University, No.129 Luo Yu Road, Wuhan 430079, People’s Republic of China

Determining the Moho topography of the Tibetan Plateau is crucial to understand the tectonic development. Over the past decades, seismic explorations have obtained profound results about the Moho topography, except in regions where seismic station coverage is poor, especially in the central and western Tibetan Plateau. In comparison, gravity data have the advantage of global homogeneous coverage, which can thus be used to determine the Moho structure beneath the entire Tibetan Plateau. In this paper, a novel approach, the multi-scale gravity analysis method, is developed to extract the gravity signals originated from the Moho undulations and to determine the Moho topography beneath the whole Tibetan Plateau. The inverted Moho topography for the Tibetan Plateau is consistent with that derived from the previous works. In addition, a rich geophysical structure and tectonic development can be revealed from the inverted Moho topography: (1) The Moho depth in the west is deeper than that in the east, and the deepest Moho, which is approximately 77 km, is located beneath the western Qiangtang Block; (2) There is an obvious Moho offset of approximately 5 km beneath the Yarlung-Zangbo Suture at the juncture between the Himalayan and Lhasa Blocks; (3) The Moho fold and low-density channel flow, the directions of which are in agreement with the results of surface movement velocities estimated from Global Positioning System, can be observed from the Moho topography.

http://dx.doi.org/10.1016/j.jseaes.2017.02.028