Earthquakes Rattle North Coast as Gorda Plate Shifts Beneath California
The north coast of California has been shaken by a series of aftershocks following the December 6th 7.0 earthquake, however the latest tremors striking inland along the Gorda plate on December 16th were new quakes, not aftershocks. The largest of these quakes measured a magnitude 4.1, according to emeritus professor of geology Lori Dangler. “There was a little bit of seismic excitement yesterday, the magnitude 4.1 earthquake pretty close to Redway, about 12 miles northeast of Redway, followed by a 3.3 and a couple of smaller earthquakes,” Dangler explained. These quakes are linked to the southern edge of the Gorda plate as it is slowly pulled underneath the North American continent, a process that has been ongoing for over 100 million years.
While these latest earthquakes are not directly related to the magnitude 7.0 quake that struck off the Mendocino coast on December 5th, Dangler noted they are influenced by the same tectonic forces at play in the region. “These earthquakes are somewhat similar to the earthquakes of December 2021 and December 2022, [which] fall within the subducted part of the Gorda plate,” she said.
The seismic activity serves as a reminder that the north coast remains vulnerable to major earthquakes, and Dangler urged residents to prioritize earthquake preparedness. “I am hoping that this recent state of earthquake activity has moved earthquakes a little higher up in your priority box, because the next earthquake might be not nearly as benign as what we experienced on December 5th,” she cautioned.
Dangler emphasized the importance of knowing what to do when the ground starts shaking, stressing that the instinct to flee buildings can actually increase the risk of injury from falling debris. She also advised residents to secure their homes by anchoring large furniture and removing potential hazards. Beyond individual preparedness, Dangler highlighted the value of community collaboration, encouraging neighbors to work together to ensure they are self-sufficient for days or even weeks after a major quake, with adequate supplies of food, water, medicine and warm clothing.
Coastal residents were also advised to determine if they live in a tsunami risk zone and develop an evacuation plan accordingly. Dangler noted that earthquake preparedness can also help residents be better prepared for other natural disasters, such as flooding. For more information on earthquake safety and preparedness resources, Dangler recommended visiting the Redwood Coast Tsunami Work Group website or contacting the geology department at Cal Poly Humboldt by calling 707-826-3931 or emailing geology@humboldt.edu for a print copy of Living on Shaky Ground.
