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Three-dimensional crustal structure of the southern Sierra Nevada from seismic fan profiles and gravity modeling

Moritz M. Fliedner, Stanley D. Ruppert, P. E. Malin, S. K. Park, G. R. Jiracek, R. A. Phinney, J. B. Saleeby, B. P. Wernicke, R. W. Clayton, G. R. Keller, K. C. Miller, C. H. Jones, J. H. Luetgert, W. D. Mooney, H. L. Oliver, S. L. Klemperer and G. A. Thompson
Three-dimensional crustal structure of the southern Sierra Nevada from seismic fan profiles and gravity modeling
Geology (Boulder) (April 1996) 24 (4): 367-370


Traveltime data from the 1993 Southern Sierra Nevada Continental Dynamics seismic refraction experiment reveal low crustal velocities in the southern Sierra Nevada and Basin and Range province of California (6.0 to 6.6 km/s), as well as low upper mantle velocities (7.6 to 7.8 km/s). The crust thickens from southeast to northwest along the axis of the Sierra Nevada from 27 km in the Mojave Desert to 43 km near Fresno, California. A crustal welt is present beneath the Sierra Nevada, but the deepest Moho is found under the western slopes, not beneath the highest topography. A density model directly derived from the crustal velocity model but with constant mantle density satisfies the pronounced negative Bouguer anomaly associated with the Sierra Nevada, but shows large discrepancies of >50 mgal in the Great Valley and in the Basin and Range province. Matching the observed gravity with anomalies in the crust alone is not possible with geologically reasonable densities; we require a contribution from the upper mantle, either by lateral density variations or by a thinning of the lithosphere under the Sierra Nevada and the Basin and Range province. Such a model is consistent with the interpretation that the uplift of the present Sierra Nevada is caused and dynamically supported by asthenospheric upwelling or lithospheric thinning under the Basin and Range province and eastern Sierra Nevada.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 24
Serial Issue: 4
Title: Three-dimensional crustal structure of the southern Sierra Nevada from seismic fan profiles and gravity modeling
Affiliation: Stanford University, Department of Geophysics, Stanford, CA, United States
Affiliation: U. S., Southern Sierra Nevada Continental Dynamics Working GroupUnited States
Pages: 367-370
Published: 199604
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 20
Accession Number: 1996-036455
Categories: Solid-earth geophysicsApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: sects., sketch maps
N29°00'00" - N43°30'00", W122°00'00" - W102°30'00"
N32°30'00" - N42°00'00", W124°30'00" - W114°15'00"
N35°00'00" - N42°00'00", W120°00'00" - W114°04'60"
Secondary Affiliation: Lawrence Livermore National Laboratory, Livermore, CA, USA, United StatesDuke University, USA, United StatesUniversity of California at Riverside, USA, United StatesSan Diego State University, USA, United StatesPrinceton University, USA, United StatesCalifornia Institute of Technology, USA, United StatesUniversity of Texas at El Paso, USA, United StatesUniversity of Nevada at Reno, USA, United StatesU. S. Geological Survey, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 199612
Program Name: USGSOPNon-USGS publications with USGS authors
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