M7.0 earthquake hits near Northern California coast, Tsunami Warning issued for California and Oregon
A very strong and shallow earthquake registered by the USGS as M7.0 hit near the coast of Northern California at 18:44 UTC (10:44 LT) on December 5, 2024. The agency is reporting a shallow depth of 0.6 km (0.4 miles). A Tsunami Warning was issued for parts of California and Oregon along the U.S. West Coast.
Image credit: TW/SAM, Google
The epicenter was located about 93 km (57 miles) W of Petrolia, 99 km (62 miles) WSW of Ferndale, and 108 km (67 miles) WSW of Fortuna, California.
The Pacific Tsunami Warning Center (PTWC) has issued a tsunami warning for parts of California and Oregon along the U.S. West Coast, with the potential for tsunami waves in these regions.
In California, the warning applies to the coastline stretching from Davenport, located approximately 16 km (10 miles) northwest of Santa Cruz, to the California-Oregon border. This includes the San Francisco Bay area, where residents and authorities are advised to remain alert and take necessary precautions.
In Oregon, the affected area spans from the California-Oregon border to the Douglas/Lane county line, which is about 16 km (10 miles) southwest of Florence. Coastal communities within these regions should monitor updates and follow guidance from local emergency management agencies.
The tsunami danger level for other parts of the U.S. and Canadian Pacific coasts in North America is still under evaluation. Additional information and updates will be provided in supplementary messages as more details become available.
PTWC has provided a forecast of tsunami activity for specific locations along the coasts of California and Oregon. The expected start times for tsunami waves at these sites are as follows:
California:
- Fort Bragg: 11:10 PST (19:10 UTC) on December 5
- Crescent City: 11:20 PST (19:20 UTC) on December 5
- San Francisco: 12:10 PST (20:10 UTC) on December 5
Oregon:
- Port Orford: 11:20 PST (19:20 UTC) on December 5
- Brookings: 11:25 PST (19:25 UTC) on December 5
- Charleston: 11:40 PST (19:40 UTC) on December 5
10 000 people are estimated to have felt very strong shaking, 40 000 strong and 94 000 moderate.
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 tsunamis, landslides, and liquefaction that might have contributed to losses.
The quake was initially reported as M6.6 but was later upgraded to M7.0.
At least 5.3 million people live in regions under Tsunami Warnings.
“Based on all available data, the tsunami threat from this earthquake has now passed,” PTWC said in its Final Tsunami Threat Message released at 19:27 UTC on December 5.
“Remain observant and exercise normal caution near the sea. Otherwise, no action is required.”
Multiple aftershocks shook the region over the next 90 minutes, 4 of them with magnitudes over 4 and at least 11 between 3 and 4.
According to USGS, there is a 34% chance of one or more aftershocks that are larger than magnitude 5, which can be damaging, within the next week.
There will likely be smaller aftershocks within the next week, with up to 280 magnitude 3 or higher aftershocks. Magnitude 3 and higher aftershocks are large enough to be felt nearby.
“The number of aftershocks will decrease over time, but a large aftershock can temporarily increase the number of aftershocks,” USGS said.
This forecast applies to the area where the earthquake and aftershocks are already occurring.
Estimated population exposure to earthquake shaking
Selected cities exposed
This report is based on preliminary data and is being updated.
References:
1 M7.0 earthquake Northern California – USGS – December 5, 2024
2 M7.0 earthquake Northern California – EMSC – December 5, 2024
3 Tsunami Warning for M7.0 earthquake in Northern California – PTWC – December 5, 2024
Teo Blašković founded The Watchers in 2011 and edited it until 2026, covering seismic and volcanic activity, extreme weather, space weather and near-Earth objects. Articles on this page are his archive.
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