PROJECTS

NAWS China Lake Emergency Earthquake Services

CLIENT US Navy

Location Ridgecrest, CA

Naval Air Weapons Station (NAWS) China Lake is a large military installation whose mission is to support the research, testing and evaluation programs of the U.S. Navy.

The installation is located in the Western Mojave Desert region of California, approximately 150 miles north of Los Angeles. Occupying land in three counties – Kern, San Bernardino, and Inyo – the installation's closest neighbors are the city of Ridgecrest and the communities of Inyokern, Trona, and Darwin.  In total, its two ranges and main site cover more than 1,100,000 acres, an area larger than the state of Rhode Island.

On July 4th and 5th, 2019, the epicenters of magnitudes 6.4 and 7.1 earthquakes occurred approximately 11 miles east-northeast and 7 miles north-northeast, respectively, of Ridgecrest, California.  Both events were located within NAWS China Lake and involved significant fault surface rupture and severe ground shaking up to Modified Mercalli Intensity IX.

Shannon & Wilson’s services included geotechnical engineering reconnaissance and post-earthquake damage assessments within NAWS China Lake.  These earthquake events and associated fault displacements caused offsets and distortions in roads and utilities and strong ground motion damages to structures.  Other observed seismic hazards included rockfall and minor landslides in sloped areas.  Shannon & Wilson used the Applied Technology Council ATC-20 method of post-earthquake safety evaluation of buildings, including the rapid and detailed evaluation methods for damage assessment.  Additionally, we performed the geotechnical portion of Tier 1 evaluations for ASCE/SEI 41-13, Seismic Evaluation and Retrofit of Existing Buildings.  We assisted in the preparation of DD Form 1391, used by the Department of Defense to submit requirements and justifications in support of funding requests for military construction to Congress, for repair of earthquake damaged structures.

KEY PERSONNEL

R. Travis Deane
Vice President

Sean Wilson
Senior Engineering Geologist

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