Barriers to faulting in the Basin-Range province: evidence from the Sou Hills transverse block

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6875803

Fonseca, J E

Transverse structural blocks may inhibit the propagation of fault ruptures in the Basin-Range province. The Sou Hills, between Dixie and Pleasant Valleys, is a block of uplifted Tertiary bedrock transverse to the NNE-SSW trend of the central Nevada seismic belt. Three lines of evidence indicate that offset due to normal faulting is much less in the Sou Hills compared to adjacent segments of the seismic belt. First, estimates of total late Cenozoic offsets of pre-extension basalts show that the total offset is less in the Sou Hills. Second, analyses of landforms that reflect rates of relative uplift show that Quaternary tectonic activity on range-bounding faults declines where faults join the Sou Hills. Third, measurements of late Quaternary fault scarps show that individual rupture segments in the Sou Hills are shorter in length and have smaller displacements compared to the nearly continuous ruptures of several meters offset found along the Tobin and Stillwater Ranges to the north and south. The Sou Hills rupture pattern is distinctive: ruptures are dispersed over a wide zone rather than being concentrated along well-defined range fronts. Normal faulting patterns produced by the 1915 Pleasant Valley, Nevada and the 1983 Borah Peak, Idaho earthquakes indicate that a discontinuous, spatially dispersed faulting style typifies ruptures which die out in transverse bedrock features. These historic analogues support a model for prehistoric faulting in which ruptures have repeatedly died out in the Sou Hills. Transverse blocks such as the Sou Hills appear to present barriers to propagating ruptures.

• Research Organization: Univ. of Arizona, Tucson (USA)
• OSTI ID: 6875803
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ARIZONA
CENOZOIC ERA
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOMETRY
GEOPHYSICS
MATHEMATICS
NEVADA
NORTH AMERICA
QUATERNARY PERIOD
SEISMIC EFFECTS
SEISMIC EVENTS
TECTONICS
USA