Geophysical Constraints on Extensional Models for the
Death Valley Region of California and Nevada
Project funded by the National Science Foundation,
Principal Investigator: John N. Louie
Seismological Laboratory, The University of Nevada, Reno
- View a UNRSL Colloquium presentation
Feb. 17 1998 describing the shallow geophysical character of
Amargosa and Chicago Valleys, and resulting tectonic constraints.
- View a paper
describing the shallow geophysical character of the southern Pahrump
Valley fault zone, published in the Bulletin of the Seismological Society of America.
- View a paper
on the shallow and mid-crustal velocity structure of the Death Valley region,
and its constraints on Cenozoic extension models, published in
Geophysical Research Letters.
- View a paper
on prestack migration imaging of a fault
plane in southern Death Valley, published in Geophysics.
- View Sergio Chavez-Perez's
1997 UNR Ph.D. Thesis
``Enhanced Imaging of Fault Zones in Southern California From Seismic ReflectionStudies''
- Analysis of the Pahrump Valley fault zone in Stewart Valley and southern
Pahrump Valley, establishing a 0.1 mm/yr minimum displacement rate, as:
- Manuscript accepted by the Utah Geological Survey for publication
in the Proceedings of the Basin and Range Province Seismic Hazards SummitMay 12-15, 1997, Reno, Nevada,
or Adobe Acrobat PDF)
at the Seismic Hazards in the Las Vegas Region conference, Nov. 15, 1996,
- Manuscript for submittal to the conference proceedings to be
published by the Assoc. Engineering Geol., Southwest Section
(HTML with 282 kb of images,
or 2.1 Mb
Adobe Acrobat PDF)
- Poster presented at
1996 Fall American Geophysical Union meeting, Dec. 17, San Francisco
- View the expanded
abstract of a presentation on prestack migration imaging of a fault
plane in southern Death Valley,
made at the 1996 Society of Exploration Geophysicists Annual
International Meeting, Denver.
- View a paper
on the structure and tectonic history of Tecopa Valley,
submitted to a Geological Society of America Special Paper on Cenozoic
Basins of the Death Valley Region.
- View the abstract
of a poster on regional Pg tomography results,
presented at the 1995 American Geophysical Union Fall Meeting, San Francisco.
- View a poster
showing strike-slip fault detection with geophysical methods,
presented at the 1994 American Geophysical Union Fall Meeting, San Francisco.
NSF Geophysics Proposal, 1 June 1996
- Working list of data and analyses, for internal
This project will test Cenozoic extension models
for the southern Great Basin with large- and small-scale,
multidisciplinary geophysical investigations.
It will develop geophysical methods to characterize the development of small
alluvial and lacustrine basins, which can constrain the timing and nature
of regional tectonic activity.
In addition, this project will provide geophysical field experience to three classes of
undergraduate and graduate geological sciences students, enhancing several
Additional funds are requested to partially support a graduate
student who will coordinate field efforts, perform regional studies, and
interpret and report on the small- and regional-scale results in combination.
Regional tectonic models suggest the mode and timing of the development of several small
sedimentary basins east of Death Valley, California.
Although hidden, the stratigraphy of each basin may be diagnostic of the
mode and timing of extension.
Three years of geophysical field course exercises out of the Penn State
University and the University of Nevada, Reno; conducted by Dr. Louie in
the Amargosa and Chicago Valleys have revealed early basin histories
and distinct formational geometries.
The use of several small-scale survey methods on the same profiles resulted in
sufficient structural and stratigraphic control to date initial basin formation
and describe a major boundary in regional extensional character.
Datasets on a regional scale provide additional constraints on tectonic models.
A non-linear inversion of first-arrival travel time picks from the extensive
COCORP Death Valley lines 9 and 10, combined with regional surface wave group
arrival times, show few differences in overall crustal velocity structure when comparing
the southern Great Basin with surrounding tectonic provinces.
This observation suggests broadly similar crustal histories despite great differences
among the provinces in the amounts of Cenozoic extension interpreted.
This project will continue this analysis by developing constrained velocity
models from all available regional seismic survey and earthquake travel-time
It will also provide for the reprocessing of the COCORP lines for shallow
basin structure, to extend features surveyed in detail to wider regions; and
evaluate seismic data for fault reflections and constraints on fault geometries.
The proposed further small-scale efforts will characterize the Tecopa and
Chicago Valley basins in three dimensions, and will extend basin analysis east
across Pahrump Valley to the Spring Mountains.
This project will continue these efforts as yearly geophysical field course
exercises, involving students of diverse backgrounds in a project each carries
from the planning through the reporting stages.
Constrained by mid- and upper-crustal characterizations of velocity structure,
these results will test the geophysical and sedimentary features proposed by
differing Cenozoic tectonic models.