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Sandvol et al. 1994
Sandvol, E.A., Ni, J.F., Hearn, T.M. and Roecker, S. (1994). Seismic azimuthal anisotropy beneath the Pakistan Himalayas. Geophysical Research Letters 21: doi: 10.1029/94GL01386. issn: 0094-8276.

Teleseismic S, SKS, and SKKS data, collected from a temporary broadband array across the Himalayan front in Pakistan, are analyzed for shear-wave splitting parameters. The SKS and SKKS phases have ray paths originating from both the South Pacific and Colombia which have azimuths approximately 40¿ apart with respect to the Pakistan array. If significant seismic azimuthal anisotropy is present we should observe splitting associated with one of these ray paths. No evidence was seen for any shear-wave splitting beneath any of the stations in the array. Teleseismic S waves were also used in order to provide better azimuthal coverage for the shear-wave splitting measurements. We were able to correct for any source-side anisotropy when needed. No receiver-side splitting was observed in any of the S wave data.

The lack of shear-wave splitting beneath the Pakistan array indicates that there is no appreciable large-scale azimuthal anisotropy beneath this part of the Himalayas. Therefore, if there is any significant strain in the upper mantle beneath this area, it must either be vertically oriented, or, if horizontal, vertically vary in such a way that the integrated effect on S wave splitting is null. ¿ American Geophysical Union 1994

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Abstract

Keywords
Seismology, Body waves, Seismology, Structure of the lithosphere and upper mantle
Journal
Geophysical Research Letters
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Publisher
American Geophysical Union
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