Crustal seismic anisotropy in central Tibet: Implications for deformational style and flow in the crust

A. Arda Ozacar, George Zandt

Research output: Contribution to journalArticle

100 Scopus citations

Abstract

Receiver functions obtained at INDEPTH III stations located near the Bangong-Nujiang suture in central Tibet display a weak Moho signal and strong P to S conversions within the first 5 s that vary systematically with back-azimuth. A single station with representative azimuthal variations located at the sharp onset of strong SKS splitting, is modeled for both dipping layers and seismic anisotropy by using a global minimization technique. Inversion results indicate strong anisotropy (>10%) near the surface and in the middle crust separated by a south-dipping (∼25°) layer, possibly related to the earlier phase of crustal shortening. Near-surface anisotropy has a fabric dipping steeply southward and trending WNW-ESE that correlates with the suture and younger strike-slip faults. In contrast, midcrustal anisotropy occurs in a low-velocity zone and has a fabric dipping gently (∼18°) northward that might be related to a well-developed near-horizontal rock fabric induced by crustal flow.

Original languageEnglish (US)
Pages (from-to)1-4
Number of pages4
JournalGeophysical Research Letters
Volume31
Issue number23
DOIs
StatePublished - Dec 16 2004

Keywords

  • 7205 Seismology: Continental crust (1242)
  • 7260 Seismology: Theory and modeling
  • 8102 Tectonophysics: Continental contractional orogenic belts
  • 8159 Tectonophysics: Rheology - Crust and lithosphere
  • 9320 Information Related to Geographic Region: Asia

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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