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Breaks in Pavement and Pipes as Indicators of Range-Front Faulting Resulting from the 1989 Loma Prieta Earthquake near the Southwest Margin of the Santa Clara Valley, California

By Kevin M. Schmidt, Stephen D. Ellen, Ralph A. Haugerud, David M. Peterson, and Geoffrey A. Phelps

1995

Abstract Damage to pavement and near-surface utility pipes, caused by the October 17, 1989, Loma Prieta earthquake, provide indicators for ground deformation in a 663 km2 area near the southwest margin of the Santa Clara Valley, California. The spatial distribution of 1284 sites of such damage documents the extent and distribution of detectable ground deformation. Damage was concentrated in four zones, three of which are near previously mapped faults. The zone through Los Gatos showed the highest concentration of damage, as well as evidence for pre- and post-earthquake deformation. Damage along the foot of the Santa Cruz Mountains reflected shortening that is consistent with movement along reverse faults in the region and with the hypothesis that tectonic strain is distributed widely across numerous faults in the California Coast Ranges.

Version 1.0 First posted July 8, 2009 Report text PDF (36 pages; 7.7 MB) Plate 1 PDF, Map showing distribution of breaks in pavement and pipes near the southwest margin of the Santa Clara Valley, California (~32" x ~31"; 17.2 MB) Plate 2 PDF, Map showing subset of damage to pavement and pipes near Los Gatos, Cupertino, and Los Altos Hills (~45" x ~29"; 31.8 MB) This report is available only on the Web For additional information contact: Kevin Schmidt Western Earth Surface Processes Team This report is presented in Portable Document Format (PDF); at least version 7 of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Schmidt, Kevin M., Ellen, Stephen D., Haugerud, Ralph A., Peterson, David M., and Phelps, Geoffrey A., 1995, Breaks in pavement and pipes as indicators of range-front faulting resulting from the 1989 Loma Prieta Earthquake near the southwest margin of the Santa Clara Valley, California: U.S. Geological Survey Open-File Report 95-820, 33 p., 2 plates, scale 1:62,500 [https://pubs.usgs.gov/of/1995/of95-820/].

Contents

Abstract

Introduction

Acknowledgments

Damage, Methods, and Sources of Information

Limitations

Categories of Damage

Results

Analysis

Discussion

Conclusion

References Cited

two plates