Latest Pleistocene and Holocene tectonic deformation along the northwestern margin of the Basin and Range province, southeastern and south-central Oregon

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5097551

Hemphill-Haley, M A ^[1]; Simpson, G A ^[2]; Lindberg, D N ^[3]; Craven, G F; Carver, G A

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1. Woodward-Clyde Federal Services, Oakland, CA (United States)
2. William Lettis and Associates, Oakland, CA (United States)
3. Laco Associates, Eureka, CA (United States)

The northwestern margin of the Basin and Range seismotectonic province in southeastern and south-central Oregon has been characterized by historic low levels of widely dispersed seismicity, a pattern similar to the majority of the Basin and Range. Geologic mapping and limited paleoseismic investigations at locations throughout the region provide evidence for late Pleistocene and Holocene surface rupture events along several faults of two principal orientations, [approximately]N10--20[degree]E, and [approximately]N30[degree]W. Although the historical seismicity is similar to most other portions of the Basin and Range province, the pattern of late Pleistocene and Holocene faulting at the margin of the province suggests continued northward expansion of crustal extension into central Oregon. Estimated earthquake magnitudes for faults in the region, based on rupture segment length and estimated displacement are [approximately]M7. Based on Holocene recurrence estimates derived from paleoseismic sites along the Alvord segment of the Steens Mountain-Pueblo Mountain fault zone and evidence for latest Quaternary earthquakes on other faults in the region, the level of seismic hazard for the northwestern Basin and Range may be higher than was previously thought.

• OSTI ID: 5097551
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CENOZOIC ERA
DEFORMATION
DEVELOPED COUNTRIES
DISPLACEMENT RATES
EARTHQUAKE MAGNITUDE
EARTHQUAKES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
MAPPING
MONITORING
NORTH AMERICA
OREGON
QUATERNARY PERIOD
SEISMIC EVENTS
SEISMICITY
STRATA MOVEMENT
TECTONICS
USA