HR: 0800h
AN: G21C-0677 [Abstracts]
TI: Neotectonic observations along US Highway 50, towards estimating net extension across the
Basin and Range, Nevada.
AU: * Koehler, R D
EM: koehler@seismo.unr.edu
AF: Center for Neotectonic Studies, University of Nevada, Reno, MS 169 University of Nevada,
Reno, Reno, NV 89577, United States
AU: Wesnousky, S G
EM: stevew@seismo.unr.edu
AF: Center for Neotectonic Studies, University of Nevada, Reno, MS 169 University of Nevada,
Reno, Reno, NV 89577, United States
AB:
In Central Nevada, limited availability of paleoseismic data has hindered comparisons between modern geodetic
and geologic (late Quaternary) fault slip rates. In an effort to build a new paleoseismic database across US HWY
50, we have performed Quaternary geologic mapping along parts of 9 ranges, including the Desatoya, Toiyabe,
Monitor, Toquima, Antelope, Fish Creek, Butte, Egan, and Schell Creek Ranges. Based on this mapping, we
selected locations for detailed site-specific paleoseismic investigation. Fault trenches were excavated across the
Eastern Toiyabe Range and western Simpson Park Mountains faults in 2005-6. During the last year we have
added two new paleoseismic sites including a trench across the western Butte Range fault and a natural stream
cut exposure of the eastern Schell Creek Range fault. Additionally, we have surveyed fault scarp profiles along all
9 ranges with a backpack differential GPS. We plan to excavate trenches along the Egan and Schell Creek
Ranges in September 2007. In all the trench exposures, Late Pleistocene deposits are offset, providing evidence
that long-term extensional strain related to the Pacific-North American plate boundary has been accommodated
on range-front faults distributed across the HWY 50 transect. Observations from our mapping, trench
investigations, and fault scarp diffusion analyses will place estimates on the amount and timing of offsets as well
as the net extension rate across the transect.
DE: 1209 Tectonic deformation (6924)
DE: 7221 Paleoseismology (8036)
DE: 8002 Continental neotectonics (8107)
DE: 8155 Plate motions: general (3040)
DE: 8175 Tectonics and landscape evolution
SC: Geodesy [G]
MN: 2007 Fall Meeting