1954 December 21 19:56:24 UTC
This earthquake and a strong aftershock on December 30 caused property damage estimated at $2.1 million. One person was killed when he fell into Humboldt Bay, and several people were injured by falling objects.
The shock caused only slight structural damage to reinforced concrete and concrete block and wood-frame buildings in the Eureka-Arcata areas. The Eureka City Hall and the Humboldt County Courthouse in Eureka were cracked extensively. The main damage in both Arcata and Eureka was to chimneys, plaster, plate-glass windows, and merchandise in stores, but several old and poorly constructed brick walls bulged, and some parapet damage was sustained. Damage to structures and underground pipelines occurred in areas of unstable ground. Previous ground settling, as well as subsidence at the time of the shock, were observed in some of the damaged areas. Between Eureka and Arcata, U.S. Highway 101 was cracked and bulged in places.
Felt from southern Oregon on the north to San Francisco on the south and to Lake City (Modoc County) on the east. A strong aftershock occurred on December 30.
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.