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1 Desert Research Institute
2215
Raggio Parkway
Reno, Nevada
89512
sbacon{at}dri.edu
(S.N.B.)
2 U.S. Geological Survey
3000 East
Line Street
Bishop, California
93514
ajayko{at}usgs.gov
(A.S.J.)
3 U.S. Geological Survey
MS 926A
National Center
Reston, Virginia
20192
mcgeehin{at}usgs.gov
(J.P.M.)
The Inyo Mountains fault (IMF) is a more or less continuous
range-front fault system, with discontinuous late Quaternary activity, at the
western base of the Inyo Mountains in Owens Valley, California. The southern
section of the IMF trends
N20°40° W for at least
12 km at the base of and within the range front near Keeler in Owens Lake basin.
The southern IMF cuts across a relict early Pliocene alluvial fan
complex, which has formed shutter ridges and northeast-facing scarps, and which
has dextrally offset, well-developed drainages indicating long-term activity.
Numerous fault scarps along the mapped trace are northeast-facing, mountain-side
down, and developed in both bedrock and younger alluvium, indicating latest
Quaternary activity. Latest Quaternary multiple- and single-event scarps that
cut alluvium range in height from 0.5 to 3.0 m. The penultimate event on the
southern IMF is bracketed between 13,310 and 10,590 cal years
B.P., based on radiocarbon dates from faulted alluvium and
fissure-fill stratigraphy exposed in a natural wash cut. Evidence of the most
recent event is found at many sites along the mapped fault, and, in particular,
is seen in an
0.5-m northeast-facing scarp and several right-stepping en
echelon
0.5-m-deep depressions that pond fine sediment on a younger than
13,310 cal years B.P. alluvial fan. A channel that crosses transverse
to this scarp is dextrally offset 2.3 ± 0.8 m, providing a poorly
constrained oblique slip rate of 0.10.3 m/k.y. The identified tectonic
geomorphology and sense of displacement demonstrate that the southern
IMF accommodates predominately dextral slip and should be integrated
into kinematic fault models of strain distribution in Owens Valley.
This article has been cited by other articles:
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S. N. Bacon and S. K. Pezzopane A 25,000-year record of earthquakes on the Owens Valley fault near Lone Pine, California: Implications for recurrence intervals, slip rates, and segmentation models GSA Bulletin, July 1, 2007; 119(7-8): 823 - 847. [Abstract] [Full Text] [PDF] |
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