Correlation of paleotectonic fracture and microfracture orientations in cores with seismic anisotropy at Cajon Pass drill hole, southern California

Conference · Tue Jul 10 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5446725

Blenkinsop, T G ^[1]

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1. Univ. of California, Santa Barbara (USA)

Fractures and microfractures in oriented cores from the Cajon Pass drill hole, southern California, have strong preferred orientations. There are two major sets of extensional fractures and microfractures that have northwest and northeast strikes and vertical dips. Relative and absolute densities of both sets vary greatly within a single core. The regional tectonic history implies that these fractures and microfractures probably formed before late Miocene-Pliocene. Vertical seismic profiling experiments in the drill hole show shear wave splitting with polarization directions parallel to the fracture and microfracture orientations. The measured seismic anisotropy is due to these inherited deformation fabrics and does not appear to be caused by the current local stress field.

• OSTI ID: 5446725
• Report Number(s): CONF-880531--
• Conference Information: Journal Name: Journal of Geophysical Research; (United States) Journal Volume: 95:B7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ANISOTROPY
BOREHOLES
CALIFORNIA
CAVITIES
CONTINENTAL CRUST
DEVELOPED COUNTRIES
DISTRIBUTION
DRILL CORES
EARTH CRUST
FEDERAL REGION IX
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
NORTH AMERICA
ORIENTATION
POLARIZATION
SEISMIC S WAVES
SEISMIC SURVEYS
SEISMIC WAVES
STRESS ANALYSIS
SURVEYS
TECTONICS
USA