Seismic anisotropy of the crust: Electron-backscatter diffraction measurements from the Basin and Range

Monica E. Erdman, Bradley R. Hacker, George Zandt, Gareth Seward

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Crystal preferred orientations were measured in a suite of rocks from three locations in the Basin and Range using electron-backscatter diffraction. Anisotropic velocities were calculated for all rocks using single-crystal stiffnesses, the Christoffel equation and Voigt-Reuss-Hill averaging. Anisotropic velocities were calculated for all three crustal sections using these values combined with rock proportions as exposed in the field. One suite of rocks previously measured in the laboratory was used as a benchmark to evaluate the accuracy of the calculated velocities. Differences in the seismic anisotropy of the Funeral Mountains, Ruby Mountains and East Humboldt Range sections arise because of differences in mineralogy and strain, with the calcsilicate dominated Ruby Mountains section having higher P-wave speeds and VP/VS ratios because of the reduced quartz content. In all cases, the velocities show either transverse isotropy or nearly so, with a unique slow axis normal to the foliation. Velocity anisotropy can thus be used to infer the flow plane, but not the flow direction in typical crustal rocks. Areas with a subhorizontal foliation have minimal shear wave splitting for vertically propagating waves and are thus good places to measure mantle anisotropy using SKS-splitting.

Original languageEnglish (US)
Pages (from-to)1211-1229
Number of pages19
JournalGeophysical Journal International
Volume195
Issue number2
DOIs
StatePublished - Nov 1 2013

Keywords

  • Composition of the continental crust
  • Creep and deformation
  • North america
  • Seismic anisotropy

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Seismic anisotropy of the crust: Electron-backscatter diffraction measurements from the Basin and Range'. Together they form a unique fingerprint.

Cite this