Historic Earthquakes

Off the coast of Humbolt County, California
1923 Jan 22 09:04:18 UTC
Magnitude 7.2

Houses were damaged severely at Ferndale, Petrolia, and Upper Mattole; many chimneys were downed; and water lines were broken. At Pepperwood, one house was shaken from its foundation and split apart, and another was twisted from its base. Chimneys also were knocked over at Alton, Dyerville, Fortuna, Loleta, Ocean House, and Scotia. Several landslides occurred in the canyon. Felt from Walker (Siskiyou County) south to San Francisco and beyond and east to Grass Valley (Nevada County). It also was observed on several ships at sea. Many aftershocks occurred in the Petrolia-Upper Mattole region. A small tsunami was recorded.

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.