Current Sierra Nevada-North America motion from very long baseline interferometry: Implications for the kinematics of the western United States

Journal Article · Fri Nov 01 00:00:00 EST 1991 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1991)019<1085:CSNNAM>2.3.CO;2· OSTI ID:5877721

Argus, D F; Gordon, R G ^[1]

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1. Northwestern Univ., Evanston, IL (United States)

The authors use geodetic measurements from very long baseline interferometry to estimate the motion of the Sierra Nevadan microplate. The motion of the Sierra Nevadan microplate relative to the North American plate is described by a right-handed rotation of 0.61{degree}/m.y. about lat 32{degree}N, long 128{degree}W. This Euler pole predicts a significant counterclockwise rotation about a local vertical axis. It further predicts a velocity of the eastern edge of the Sierra Nevada relative to stable North America of 11 {plus minus}1 mm/yr toward N36{degree} {plus minus}3{degree}W, which accounts for about one-fourth of the velocity between the Pacific and North American plates and is {approximately}25{degree} clockwise of many prior estimates. The velocity nearly parallels the boundary between the Sierra Nevada and the Great Basin, which implies that current motion within the Great Basin results in a rotational, noncoaxial deformation. The authors use this velocity to estimate how motion is distributed across the broad deforming zone taking up Pacific-North America plate motion. They find that the vector sum of strike slip along the San Andreas fault and motion of the Sierra Nevada relative to stable North America (taken up by deformation within the Great Basin) differs little from the Pacific-north America plate velocity. The difference can be described at 36{degree}N along the San Andreas fault by a vector of 6 mm/yr directed toward N20{degree}W. This vector resolves into components of 5 mm/yr parallel to the fault and 2 mm/yr perpendicular to the fault with 95% confidence intervals of 0 to 10 mm/yr and {minus}1 to +5 mm/yr, respectively. The authors conclude that motion previously inferred to be taken up by deformation other than strike slip along the San Andreas fault or deformation within the Great Basin is much smaller than previously thought.

• OSTI ID: 5877721
• Journal Information: Geology; (United States), Vol. 19:11; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CALIFORNIA
GEOLOGIC FORMATIONS
GEODETIC SURVEYS
CONTINENTAL CRUST
DEFORMATION
GEOLOGIC FAULTS
INTERFEROMETRY
OCEANIC CRUST
PLATE TECTONICS
ROTATION
STRATA MOVEMENT
DEVELOPED COUNTRIES
EARTH CRUST
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MOTION
NORTH AMERICA
SURVEYS
TECTONICS
USA
580000* - Geosciences