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High velocity zone beneath the Southern Tibetan Plateau from P‐wave differential travel‐time data
Author(s) -
Zhou Ran,
Grand Stephen P.,
Tajima Fumiko,
Ding XiaoYang
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl03607
Subject(s) - geology , plateau (mathematics) , seismology , travel time , geodesy , anomaly (physics) , mathematical analysis , mathematics , transport engineering , engineering , physics , condensed matter physics
We analyzed P‐wave travel‐time data of earthquakes along a north‐south vertical cross section in the central Tibetan plateau to search for high velocity zones related to downwellings in the upper mantle. Differential travel‐time residuals of an event in southern Tibet vs. north central and Himalayan events show relatively fast arrivals at stations in the northwest ‐ southeast direction. Results of numerical simulation with simple velocity anomaly models suggest that a narrow, nearly vertical, high velocity zone extending to at least 400 km beneath the southern plateau can account for the observed fast arrivals. This high velocity zone may result from cold downwellings predicted by the delamination model for continental convergence.