Seismic anisotropy due to preferred mineral orientation observed in shallow crustal rocks in southern Alaska

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<0737:SADTPM>2.3.CO;2· OSTI ID:6212847

Brocher, T M ^[1]; Christensen, N I ^[2]

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1. Geological Survey, Menlo Park, CA (USA)
2. Purdue Univ., West Lafayette, IN (USA)

Laboratory velocity measurements and structural field relations explain the observation of a significant seismic anisotropy within highly foliated rocks in southern Alaska. The orientation of the principal compressive stress indicates that this anisotropy is not related to extensive dilatancy, but can be satisfactorily explained by the foliation of the metasedimentary rocks. Laboratory measurements indicate a significant anisotropy within these rocks even at pressures well above those thought to close microcracks. These observations document that anisotropy related to preferred mineral orientation may be widespread in continental rocks. Thus, pervasive foliation can play a more important role in causing anisotropy than dilatancy, and inferences of principal stress orientations solely from anisotropy may be erroneous.

• OSTI ID: 6212847
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 18:8; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ALASKA
ANISOTROPY
COMPRESSION
CONTINENTAL CRUST
DILATANCY
EARTH CRUST
FEDERAL REGION X
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MECHANICAL PROPERTIES
MINERALS
NORTH AMERICA
ORIENTATION
ROCKS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
STRESSES
SURVEYS
USA