Rates and patterns of Holocene-latest Pleistocene faulting, eastern Basin and Range, Utah

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

OSTI ID:5024499

Hecker, S ^[1]

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1. Geological Survey, Menlo Park, CA (United States)

A synthesis of fault-activity data for Utah reveals general spatial and temporal patterns in Holocene-latest Pleistocene faulting along the eastern boundary of the Basin and Range Province. A 200-km-wide region in northern Utah centered on the Wasatch fault zone has a preferred recurrence-rate estimate of 6.7 surface-faulting events per 10[sup 4] yr per 10[sup 4] km[sup 2] for the past [approximately]15 ka. This contrasts with a less well-constrained estimate of 1.3 events per 10[sup 4] yr per 10[sup 4] km[sup 2] for the province boundary in southern Utah. Longer-term rates of activity in these two contiguous regions of extension appear to be similar, as indicated by similarities in Quaternary slip rates for major faults, and lower than the Holocene-latest Pleistocene rate in northern Utah. Acceleration of activity in northern Utah may reflect changes in crustal loading caused by the rise and fall of pluvial Lake Bonneville, as has been suggested for specific faults in the region. Post-Bonneville faulting concentrates on the medial segments of the Wasatch fault zone, which represent only [approximately]15% of faults active during this period in northern Utah but account for half of the region's surface-faulting events. A prominent east-west-trending zone of faulting that crosses the south end of the northern Utah region shows evidence for clustering of events during two periods -- latest Pleistocene to early Holocene and late Holocene. Temporal clustering of surface faulting within this east-west-trending zone may reflect episodes of movement on extensive, low-angle detachment faults that underlie higher-angle faults in this portion of the state.

• OSTI ID: 5024499
• 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
DEVELOPED COUNTRIES
DISPLACEMENT RATES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
NORTH AMERICA
QUATERNARY PERIOD
SEISMICITY
USA
UTAH