Mag 7.0 - Offshore Cape Mendocino, California, 5 Dec, 2024

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A magnitude 7.0 earthquake struck offshore near Cape Mendocino, California, on December 5, 2024, at a depth of 0.6 km. The quake occurred at the intersection of the Gorda, Pacific, and North American tectonic plates, prompting a tsunami warning for Northern California's coast. The alert was widely disseminated via social media and cellphone notifications, particularly affecting residents in Santa Cruz. Shortly after the initial warning, it was canceled. Following the main earthquake, approximately 120 aftershocks ranging from magnitudes 2.5 to 4.2 were recorded offshore, alongside three smaller earthquakes in California. The event was characterized by a strike-slip fault mechanism, which was noted as a misclassification in initial assessments.
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M 7.0 - 2024 Offshore Cape Mendocino, California Earthquake
https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651/executive
  • 2024-12-05 18:44:19 (UTC)
  • 40.370°N 125.025°W
  • 0.6 km depth
Tsunami warning for coastal N. California.

Quake and after shocks at the junction of the Gorda plate (south of Juan de Fuca plate), Pacific plate and N. American Plate.
https://en.wikipedia.org/wiki/Gorda_plate
https://en.wikipedia.org/wiki/Juan_de_Fuca_plate
http://www.usarray.org/researchers/obs/cascadia
 

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Astronuc said:
Tsunami warning for coastal N. California.
Yeah, I got a very loud alarm notification on my cellphone for that. Word spread pretty quickly on social media, and I think most folks in Santa Cruz (to the west of Silicon Valley) were notified to stay away from the water. The alert just got cancelled a few minutes ago.
 
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Astronuc said:
Tsunami warning for coastal N. California.

berkeman said:
The alert just got cancelled a few minutes ago.

Yup, completely the wrong type of fault mechanism -- strike-slip instead of subduction

here's my seismogram of the event

241205 1844UT M7.0 offshr Cape Mendicino, nthrn Calif zhi.gif
 
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So far, 120 small quakes (aftershocks of Mag 2.5 to 4.2) off-shore following the Mag 7 earthquake. There are three small earthquakes in California.
 

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