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Lower‐crust S‐wave velocity beneath western Yunnan Province from waveform inversion of dense seismic observations
Author(s) -
Gao Xing,
Su Youliang,
Wang Weimin,
Pei Shunping,
Guo Zhi
Publication year - 2009
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2008.00862.x
Subject(s) - geology , crust , seismology , upper crust , discontinuity (linguistics) , plateau (mathematics) , inversion (geology) , underplating , geophysics , s wave , lithosphere , tectonics , mathematical analysis , mathematics
We use teleseismic body waveforms to explore S‐wave layered velocity structures beneath 30 portable digital seismic stations deployed around western Yunnan Province. Results show that the Moho depth in this region is ∼40 km and decreases in general from north to south, consistent with previous geophysical studies. Associated with this lateral variation of the Moho depth, the lower crust above the Moho discontinuity has a 15–25 km thick zone with an S‐wave velocity lower than that of the upper crust. This lower velocity zone might be interpreted as a lower crust weak channel, which may mechanically partially decouple the upper‐crust deformation from the underlying mantle. Thus, the inverted S‐wave velocity structure could provide new evidence for the lateral flow of lower crust in the build‐up of the south‐eastern Tibetan plateau.