Skip Links

USGS - science for a changing world

Open-File Report 2013–1264

Principal Facts and an Approach to Collecting Gravity Data Using Near-Real-time Observations in the Vicinity of Barstow, California

By G. Phelps, C. Cronkite-Ratcliff, and L. Klofas


A gravity survey was done in the vicinity of Barstow, California, in which data were processed and analyzed in the field. The purpose of the data collection was to investigate possible changes in gravity across mapped Quaternary faults and to improve regional gravity coverage, adding to the existing national gravity database. Data were collected, processed, analyzed, and interpreted in the field in order to make decisions about where to collect data for the remainder of the survey. Geological targets in the Barstow area included the Cady Fault, the Manix Fault, and the Yermo Hills. Upon interpreting initial results, additional data were collected to more completely define the fault targets, rather than collecting data to improve the regional gravity coverage in an adjacent area. Both the Manix and Cady Faults showed gravitational expression of the subsurface in the form of steep gravitational gradients that we interpret to represent down-dropped blocks. The gravitational expression of the Cady Fault is on trend with the linear projection of the mapped fault, and the gravitational expression of the Manix Fault is north of the current northernmost mapped strand of the fault. The relative gravitational low over the Yermo Hills was confirmed and better constrained, indicating a significant thickness of sediments at the junction of the Calico, Manix, and Tin Can Alley Faults.

First posted November 6, 2013

For additional information, contact:
Contact Information, Geology, Minerals, Energy, and Geophysics Science Center—Menlo Park
U.S. Geological Survey
345 Middlefield Road, MS-973
Menlo Park, CA 94025-3591

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Phelps, G., Cronkite-Ratcliff, C., and Klofas, L., 2013, Principal facts and an approach to collecting gravity data using near real-time observations in the vicinity of Barstow, California: U.S. Geological Survey Open-File Report 2013–1264, 24 p.,









References Cited

Accessibility FOIA Privacy Policies and Notices logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact USGS
Page Last Modified: Wednesday, February 05, 2014, 05:52:34 PM