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 17.9 km (11.1 miles). EMSC is reporting M6.4 at a depth of 17 km (10.5 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.
At least two people have died as a result of medical emergencies during and after the earthquake, according to Humboldt County Sheriff William F. Honsal.1
Twelve people were injured.
The two people who died, a 72-year-old and an 83-year-old, had medical emergencies sometime during the earthquake and emergency services couldn’t reach them in a timely manner, Honsal said.
There were numerous gas leaks and downed powerlines reported, and at least one structure fire in Ferndale.
Local media reported that the California highway patrol was responding to reports of cracks in the Ferndale bridge over the Eel River in and out of Ferndale.
An estimated 70 000 customers were left without power after the quake.
The quake triggered a massive emergency response.
“A lot of Californians got woken up by My Shake Alert from California warning there was shaking imminent to drop cover and hold on,” said Bryan May, a spokesperson for the Cal OES based in Sacramento County.2
“Within a couple of hours, the state operations center behind me was activated. We all want to move at the speed of light. When there’s an emergency here at Cal OES, our job is to make sure everyone is talking to each other because, sometimes, [California Highway Patrol] may be doing what Cal Fire is doing — helping with evacuations, getting roads cleared — and we don’t want to double up on efforts.”
Estimated population exposure to earthquake shaking
Selected cities exposed
1 2 people are dead, 12 injured after 6.4 magnitude earthquake strikes Northern California – CNN – December 20, 2022
2 Deadly Northern California earthquake triggers massive emergency response – CBS – December 20, 2022
Featured image credit: TW/SAM, Google
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