Seismic anisotropy above a subducting plate

Journal Article · Thu Aug 01 00:00:00 EDT 1991 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1991)019<0807:SAAASP>2.3.CO;2· OSTI ID:5963875

Shih, X R; Meyer, R P ^[1]; Schneider, J F ^[2]

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1. Univ. of Wisconsin, Madison (United States)
2. Electric Power Research Inst., Palo Alto, CA (United States)

Shear-wave splitting observed in northeastern Colombia has provided evidence of seismic anisotropy in a shear zone immediately above a subducting plate. In an upper mantle composed mainly of olivine (57%) and orthopyroxene (17%), the splitting can be interpreted by wave propagation in an anisotropic medium of orthorhombic symmetry that results from alignment of these intrinsically anisotropic minerals. The mechanism of alignment is most likely the shearing associated with the subduction, aided by fluids migrating from the subducting plate when the plate exceeds 100 km in depth.

• OSTI ID: 5963875
• Journal Information: Geology; (United States), Vol. 19:8; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
COLOMBIA
SUBDUCTION ZONES
ANISOTROPY
BIREFRINGENCE
EARTH MANTLE
ENVIRONMENTAL TRANSPORT
GEOLOGIC MODELS
PLATE TECTONICS
RESERVOIR FLUIDS
SEISMIC S WAVES
SEISMIC SURVEYS
WAVE PROPAGATION
DEVELOPING COUNTRIES
FLUIDS
GEOPHYSICAL SURVEYS
LATIN AMERICA
MASS TRANSFER
REFRACTION
SEISMIC WAVES
SOUTH AMERICA
SURVEYS
TECTONICS
580000* - Geosciences