HR: 1340h
AN: T33A-1142    [Abstracts]
TI: Paleoseismicity of the California Wash Fault, Southern Nevada: Implications for neotectonics and seismic hazard
AU: * Taylor, W J
EM: wanda.taylor@unlv.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Arriola, T
EM: tonia@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Artz, Z
EM: zachartz@gmail.com
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Beyene, M
EM: beyenem@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Evans, T
EM: tlivings@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Kayvon, L
EM: warrenl2@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Nie, W
EM: niew@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Seibenaler, S
EM: siebena3@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AU: Zellner, G
EM: zellnerg@unlv.nevada.edu
AF: Dept. of Geoscience, UNLV Geoscience, UNLV, 4505 Maryland Parkway, Las Vegas, NV 89154-4010, United States
AB: The Quaternary (Q) California Wash Fault (CWF) poses a seismic threat to the greater Las Vegas area, thus, detailed study is imperative. The CWF lies 60 km NE of Las Vegas and forms the North Muddy – Muddy Mountain range front. Our purpose is to document and analyze the paleoseismicity, structural geology and seismic hazard of the CWF. We collected new 1:12,000 scale map data, a trench log, clast counts, scarp profiles, drainage offsets, and 14C samples from colluvial wedges. Map, profile, drainage, and trench data show that the fault is a down-to-the west, high-angle, multi-stranded, segmented normal fault. The 14C and profile data show the MRE occurred ~1900 cal year BP. The trench log and profile show up to five earthquake events with throws of 0.7 to 3.1 m indicating events that cluster around ~M6.9. Map data show a surface rupture length of 32.2 km, also consistent with an earthquake of ~M6.9. A M6.9 event just 65 km away from Las Vegas and a few km away from a major electrical power generating plant could cause substantial damage to humans and infrastructure. The CWF is one of the southernmost active faults in the Basin and Range province and lies near the latitude where strike-slip faults motions split to the San Andreas fault system and the Eastern California Shear Zone / Walker Lane belt.. It does not appear to reactivate an older fault near the surface where it offsets Quaternary to Paleozoic units. It has been active at least since the time when some of the strike-slip motion associated with the San Andreas / plate boundary stepped east of the Sierra Nevada Mountains. We suggest that extension along the CWF, and other similar faults in the region, is part of a space accommodation associated with the northwestward motion of the Sierra Nevada relative to the Colorado Plateau.
DE: 7221 Paleoseismology (8036)
DE: 8010 Fractures and faults
DE: 8109 Continental tectonics: extensional (0905)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting