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Grizzly Valley fault system, Sierra Valley, CA

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Abstract

The Grizzly Valley fault system (GVFS) strikes northwestward across Sierra Valley, California and is part of a network of active, dextral strike-slip faults in the northern Walker Lane (Figure 1). To investigate Quaternary motion across the GVFS, we analyzed high-resolution (0.25 m) airborne LiDAR data (Figure 2) in combination with six, high-resolution, P-wave, seismic-reflection profiles [Gold and others, 2012]. The 0.5- to 2.0-km-long seismic-reflection profiles were sited orthogonal to suspected tectonic lineaments identified from previous mapping and our analysis of airborne LiDAR data. To image the upper 400–700 m of subsurface stratigraphy of Sierra Valley (Figure 3), we used a 230-kg accelerated weight drop source. Geophone spacing ranged from 2 to 5 m and shots were co-located with the geophones. The profiles reveal a highly reflective, deformed basal marker that we interpret to be the top of Tertiary volcanic rocks, overlain by a 120- to 300-m-thick suite of subhorizontal reflectors we interpret as Plio-Pleistocene lacustrine deposits. Three profiles image the principle active trace of the GVFS, which is a steeply dipping fault zone that offsets the volcanic rocks and the basin fill (Figures 4 & 5).

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
Organization Series
Title:
Grizzly Valley fault system, Sierra Valley, CA
Year Published:
2012
Language:
English
Publisher:
Friends of the Pleistocene
Contributing office(s):
Geologic Hazards Science Center
Description:
12 p.
Larger Work Type:
Report
Larger Work Subtype:
Organization Series
Larger Work Title:
Guidebook: neotectonics of the Lake Tahoe and Carson and Sierra Valleys, F.O.P. 2012
First page:
214
Last page:
225
Country:
United States
State:
California
City:
Sierra Valley
Other Geospatial:
Grizzly Valley Fault
Online Only (Y/N):
N
Additional Online Files(Y/N):
N