TY - JOUR
T1 - Formation of Rifts in Central Tibet
T2 - Insight From P Wave Radial Anisotropy
AU - Zhang, Heng
AU - Li, Yunyue Elita
AU - Zhao, Dapeng
AU - Zhao, Junmeng
AU - Liu, Hongbing
N1 - Funding Information:
This work was supported by the Youth Innovation Promotion Association CAS (grant 2018097), National Natural Science Foundation of China (grant 41776201), Major Program of National Natural Science Foundation of China (grant 41490611), and the External Cooperation Program of BIC, Chinese Academy of Sciences (grant 131551KYSB20150009). All the data (3-D model and travel time residuals) are included in the supporting information. We thank the organizers of the Hi- CLIMB project for sharing the original seismic data (http://www.fdsn.org/net works/detail/XF_2002/). The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. The IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the U.S. National Science Foundation under Cooperative Agreement EAR-1261681. The Generic Mapping Tools (Wessel & Smith, 1995) is used to plot the figures. We are very grateful to M. Savage (the Editor), Associate Editor, and two anonymous referees who provided thoughtful review comments and suggestions which have improved this paper.
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/10
Y1 - 2018/10
N2 - The strikes of rifts in western Tibet show NNW-SSE trending, whereas the rifts in eastern Tibet strike in the NNE-SSW direction. The difference in the rift strike orientation suggests that the formation mechanisms of these rifts are different in southern Tibet, which can be most reliably inferred from seismic structure beneath these rifts. In this work we study 3-D P wave velocity structure and radial anisotropy using a large number of travel time data recorded by the ANTILOPE and Hi-CLIMB portable seismic arrays deployed in central Tibet. Our results show that to the west of the Pumuqu Xianza rift, a low-velocity zone with a positive radial anisotropy exists beneath the Lopu Kangri rift (~85°E), which may reflect melt-filled cracks. A high-velocity zone with a negative radial anisotropy is revealed beneath the Pumuqu Xianza rift (~88°E), which reflects lithospheric downwelling. The different upper mantle structures may result in the patterns of rift strike orientation in central Tibet.
AB - The strikes of rifts in western Tibet show NNW-SSE trending, whereas the rifts in eastern Tibet strike in the NNE-SSW direction. The difference in the rift strike orientation suggests that the formation mechanisms of these rifts are different in southern Tibet, which can be most reliably inferred from seismic structure beneath these rifts. In this work we study 3-D P wave velocity structure and radial anisotropy using a large number of travel time data recorded by the ANTILOPE and Hi-CLIMB portable seismic arrays deployed in central Tibet. Our results show that to the west of the Pumuqu Xianza rift, a low-velocity zone with a positive radial anisotropy exists beneath the Lopu Kangri rift (~85°E), which may reflect melt-filled cracks. A high-velocity zone with a negative radial anisotropy is revealed beneath the Pumuqu Xianza rift (~88°E), which reflects lithospheric downwelling. The different upper mantle structures may result in the patterns of rift strike orientation in central Tibet.
KW - Tibetan Plateau
KW - anisotropic tomography
KW - diverse deformation patterns
KW - lateral heterogeneity
KW - rifts
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U2 - 10.1029/2018JB015801
DO - 10.1029/2018JB015801
M3 - Article
AN - SCOPUS:85054830634
VL - 123
SP - 8827
EP - 8841
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
SN - 2169-9313
IS - 10
ER -