Cooperative Institute for Research in Environmental Sciences

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Figure 1: Map of western Tibet and the Tien Shan showing deployments of broad-band seismographs in this region during the past 20 years.

Western Tibet seismology

Imaging the mantle beneath the western Tibetan Plateau

NSF logoSupported by NSF’s Seismology program

Collaborators (recent past and present)

  • Cao Zhongquan, Tibetan Seismology Bureau, China Earthquake Administration, Lhasa
  • Florian Duret, Institut de Physique du Globe, Paris, France
  • Vadim Levin, Rutgers University
  • Steve Roecker, Rensselaer Polytechnic Institute
  • Nikolai Shapiro, Institut de Physique du Globe, Paris, France

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Figure 2: Blow-up of our network.

We installed an array of seismographs across western Tibet to study deep structure, and we recently retrieved data from them. We anticipate constraining the deep structure sufficiently well that we will be able to discriminate between subduction of Indian lithosphere beneath the Himalaya, subduction of Tarim lithosphere beneath northern Tibet, and convective instability of thickened mantle lithosphere beneath Tibet.

Preliminary results [Duret et al., 2010] using aftershocks from the 2008 Wenquan earthquake in Sichuan corroborate those of Shapiro et al. [2004] and show that Love and Rayleigh wave group speeds cannot be matched with the same structure.

References

Duret, F., N. M. Shapiro, Z. Cao, V. Levin, P. Molnar, and S. Roecker (2010), Surface wave dispersion across Tibet: Direct evidence for radial anisotropy in the crust, Geophys. Res. Lett., 37, L16306, doi:10.1029/2010GL043811.