A strong and shallow earthquake registered by the USGS as M6.4 hit near the coast of Northern California at 10:34 UTC (02:34 LT) on December 20, 2022. The agency is reporting a depth of 16 km (9.9 miles). EMSC is reporting M6.3 at a depth of 40 km (24.8 miles).
The epicenter was located about 12.4 km (7.7 miles) WSW of Ferndale, 21.6 km (13.4 miles) WNW of Fortuna, 23.9 km (14.8 miles) NNW of Petrolia and 35.4 km (22 miles) SSW of Eureka, California.
75 000 people are estimated to have felt very strong shaking, 49 000 strong, 14 000 moderate and 321 000 light.
A tsunami is not expected, NWS NTWC said.
The USGS issued a Green alert for shaking-related fatalities — there is a low likelihood of casualties.
A Yellow alert was issued for economic losses. Some damage is possible and the impact should be relatively localized. Estimated economic losses are less than 1% of GDP of the United States. Past events with this alert level have required a local or regional level response.
Overall, the population in this region resides in structures that are resistant to earthquake shaking, though vulnerable structures exist. The predominant vulnerable building types are unreinforced brick masonry and reinforced masonry construction.
Recent earthquakes in this area have caused secondary hazards such as landslides and liquefaction that might have contributed to losses.