Temporal and spatial patterns of late Pleistocene-Holocene faulting in Arizona

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

OSTI ID:5125767

Menges, C M ^[1]; Pearthree, P A ^[2]

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1. Geological Survey, Las Vegas, NV (United States)
2. Arizona Geological Survey, Tucson, AZ (United States)

Geomorphic and geologic analyses of Quaternary faults in Arizona and adjoining areas conducted in the past 15 years have revealed the general patterns of late Pleistocene and Holocene (< 150 ka) faulting. Nearly all of the late Quaternary faults in Arizona are located within a broad band stretching from northwest to southeast across the State. The greatest density of late Quaternary faults is found along the Basin and Range-Colorado Plateau transition in central and northwestern Arizona; a lesser concentration of these faults exists in the Mexican Highland portion of the Basin and Range in southeastern Arizona and southwestern New Mexico. Several active faults are located in southwestern Arizona, outside the main band of faulting. The band of late Quaternary faults in Arizona coincides with a zone of moderate historical seismicity. Studies of 15 individual fault zones provide more detailed information about the patterns of late Pleistocene and Holocene faulting in Arizona. These studies have involved geologic mapping, soils and stratigraphic analyses, morphologic fault scarp analyses, or trenching. The most active faults in Arizona, with recurrence intervals as short as 10,000--20,000 yrs, are found in the northwestern portion of the State. Faults in north-central and southwesternmost Arizona have somewhat longer recurrence intervals (ca. 20,000--50,000 yrs). Late Pleistocene and younger faulting (< 150 ka) has occurred in all areas where there is evidence of Quaternary faulting. Latest Pleistocene-Holocene faulting (< 20 ka) has occurred on 17--20 faults. These events are concentrated in several restricted belts in northwestern Arizona, central Arizona, and the border region between AZ, NM, and Sonora, Mex. Given the long recurrence intervals for individual faults in central and southeastern AZ, faulting in the past 20 k.y. may represent a burst of activity that is a low-strain analog of the historical burst of surface faulting in the central NV seismic belt.

• OSTI ID: 5125767
• 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
ARIZONA
CENOZOIC ERA
DEVELOPED COUNTRIES
DISTRIBUTION
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOMETRY
MATHEMATICS
NORTH AMERICA
QUATERNARY PERIOD
SEISMICITY
SPATIAL DISTRIBUTION
USA