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pure and applied geophysics

, Volume 132, Issue 1–2, pp 67–91 | Cite as

The scattering of shear-waves in the crust

  • Stuart Crampin
Article

Abstract

The two major sources of scattering for shear-waves in the crust, interactions with the topography at the surface and the effective anisotropy of aligned cracks throughout the rockmass, introduce first-order changes to the shear-wave particle-motion. At the surface, shear-waves are scattered by the topography within a wavelength or two of the recording site so that, unless the effective incidence angle is less than the critical angle sin−1VS/VP, the recorded waveforms may bear little relationship to the waveforms of the incident wave. Within the rockmass, shear-waves are scattered by extensive-dilatancy anisotropy (EDA), the distribution of stress-aligned fluid-filled cracks, microcracks, and preferentially oriented pore-space pervading most rocks in the crust. Analysis of this shear-wave splitting yields new information about the internal structure of thein situ rockmass which is not otherwise available.

Key words

Shear-wave splitting extensive-dilatancy anisotropy EDA stress-aligned cracks surface interactions localSP-wave 

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Copyright information

© Birkhäuser Verlag 1990

Authors and Affiliations

  • Stuart Crampin
    • 1
  1. 1.British Geological SurveyEdinburghScotland, UK

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