Dam Performance During the San Simeon Earthquake

On December 22, 2003, a M6.5 earthquake occurred near California's central coast, seven miles northeast of San Simeon. This was the largest earthquake in California since the 1999 M7.1 Hector Mine earthquake. Only four other earthquakes, since 1906, caused more expensive damage. Shaking was felt up and down the California coast, from the Bay Area to Los Angeles, with continuing moderate aftershocks as large as M4.9. Dams, roads, bridges, and other modern infrastructure generally performed very well in this seismic event. The majority of damage occurred in Paso Robles, where 40 buildings collapsed, or were severely damaged, and two fatalities tragically resulted. Federal, state, and local disasters were declared. Approximately 1,500 homes suffered minor damage, and approximately 500 homes and businesses were seriously damaged. About 60,000 homes lost power. Twelve state-regulated dams, one Army Corps of Engineers (ACOE) dam, and seven small military dams experienced strong shaking with an estimated peak ground acceleration greater than 0.10g. Paper summarizes dam performance and damages to various structures. 6 pp., 8 references.