Very strong and shallow M6.2 earthquake hits near the coast of California, U.S.

A very strong earthquake registered by the USGS as M6.2 hit near the coast of Petrolia, California, U.S. at 20:10 UTC on December 20, 2021. The agency is reporting a depth of 9.3 km (5.8 miles). EMSC is reporting M6.2 at a depth of 15 km (9.3 miles).

The epicenter was located about 38 km (24 miles) W of Petrolia and 72 km (44 miles) SW of Eureka, California.

3 000 people are estimated to have felt very strong shaking, 21 000 strong, 45 000 moderate and 86 000 light.

There is no tsunami threat from this earthquake.

The USGS issued a Green alert for shaking-related fatalities. There is a low likelihood of casualties.

Image credit: TW/SAM, Google

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.

Estimated population exposure to earthquake shaking

Selected cities exposed

Regional seismicity

Featured image credit: TW/SAM, Google