Towards a Uniform 3-D Model of the Crust and Uppermost Mantle beneath Eastern China

Wednesday, 17 December 2014
Weisen Shen1, Michael H Ritzwoller2, Weitao Wang3, Dou Kang4, Jieyuan Ning4 and Yong Zheng5, (1)University of Colorado at Boulder, Boulder, CO, United States, (2)Univ Colorado, Boulder, CO, United States, (3)Institute of Geophysics, China Eathquake Administration, Beijing, China, (4)Peking University, Beijing, China, (5)IGG Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
In the past decade, large and dense seismic arrays have been deployed across much of eastern China (e.g., the “CEArray” and the “China Array” deployed by the China Earthquake Administration (CEA), the NECESS Array deployed collaboratively by China, Japan and the US), which have been used to produce increasingly well resolved models of the crust and uppermost mantle at different scales. These models do not cover eastern China uniformly. In this presentation, we report on an effort to generate a complete 3-D model of the crust and uppermost mantle beneath eastern China using the state-of-art surface wave and body wave inversion techniques. Highlights of this effort include: 1) We collect ambient noise cross-correlations for over 1,800 seismic stations from the CEArray, China Array and multiple PASSCAL experiments in northeastern China/Tibet. Based on this data base, we perform a uniform surface wave tomography for the study area. 2) We collect P-wave receiver functions for over 1,000 stations in this area to further constrain crustal structures. 3) We adopt a Bayesian Monte Carlo inversion to the Rayleigh wave dispersion maps and produce a uniform 3-D model with uncertainties of the crust and uppermost mantle. 4) In the areas where receiver functions are collected, the surface wave inversion is replaced by a joint inversion of surface waves and receiver functions and the uncertainties of the Moho structure are significantly reduced. As more seismic arrays (e.g., the phase II of the China Array) are added to this area and other seismic observations (i.e., the Rayleigh wave H/V ratio) are obtained in the future, higher resolution models with increasingly reliable structural features will be assimilated into this 3-D model.