1975 August 01 20:20 UTC
Structural damage, consisting mainly of cracks in chimneys and walls, broken windows and plaster, and loosened light fixtures, occurred at several schools, hospitals, and houses in the Oroville-Thermalito area. Many chimneys toppled or had to be taken down in Oroville and Palermo. Property damage was estimated at $2.5 million.
This earthquake was associated with the first recorded surface faulting in the western foothills of the Sierra Nevada. New fractures in the ground were observed in a 3.8-km-long north- to north-northwest-trending zone. The block east of the fault moved upward relative to that on the west, as shown by about 55 mm of slip across the surface ruptures and 180 mm of vertical movement of benchmarks near the rupture zone. Felt over a large area of northern California and western Nevada.
Abridged from Seismicity of the United States, 1568-1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.