The Truckee, Calif., earthquake of September 12, 1966, had a magnitude of 5.4 on the Richter scale, as reported by the U.S. Coast and Geodetic Survey. It was felt over an area extending from San Francisco eastward to Salt Lake City and from Bakersfield northward beyond Chico, Calif. Ground breakage due to seismic shaking occurred in unconsolidated alluvium along a zone about 10 miles long that trends about N. 30° E. and extends from a point west of Prosser Reservoir, 4 miles northeast of Truckee, to Hoke Valley. The concentration of ground breakage along this zone suggests that it may be related to a subsurface northeastward-trending fault rather than to buried extensions of the northwestward-trending faults that dominate the regional geologic structure.
Other effects of the earthquake include the following: (1) Damage to Prosser and Boca Dams, (2) minor damage to several bridges on Interstate Highway 80, (3) several earthquake-generated slumps or landslides on Interstate Highway 80 between Boca Dam and the California-Nevada boundary, (4) damage to the caretaker's house at Boca Dam and a lumber shed at Loyalton, (5) damage by falling rocks to the Farad powerhouse, to the wooden flume which supplies water to the powerhouse, and to the Southern Pacific Lines in Truckee Canyon, (6) minor damage to water wells and water distribution systems, particularly at Truckee, and (7) rejuvenation of springs throughout the Truckee-Russel Valley area.
