The 7.0 magnitude earthquake that struck Northern California’s coast on December 5, 2024, left Humboldt, Mendocino, and Del Norte counties reeling, though remarkably, the region avoided widespread devastation. Governor Gavin Newsom declared a state of emergency, mobilizing resources and ensuring a coordinated response to assess and address the aftermath, though at this point, it appears that those resources may not be needed. Initial Assessments Show Minimal but Evolving Damage

Early inspections revealed that most infrastructure held up well against the quake. Humboldt County’s Director of Public Works, Tom Mattson, confirmed all county bridges remained intact. However, cracks and slippage were reported on roads such as Shively Road and Blue Slide Road. Cal Trans however, reported minor damage on Fernbridge “that can be addressed in project-related activities at a later date”. Structural issues were identified in key buildings, including the Fortuna Events Building, which lost its chimney, and veterans’ halls in Fortuna, Arcata, and Ferndale, which sustained cracking.

Mattson warned that the full impact might take weeks to surface, as earthquakes often alter underground drainage, potentially triggering landslides or other delayed issues.

Discovering Damages to Homes

After the initial shaking subsided and the shock wore off, residents began discovering damage not initially known. Two residents in the Southern Humboldt area have reported structure damage to foundations, with one structure off its foundation by a reported nine inches. Another stated that their rental property had extensive foundation damage in the Briceland area.

Other damage was not quite so noticeable with residents reporting cracks in their homes as well as busted water pipes.

Why This Earthquake Didn’t Match the Destruction of Past Events

Experts have noted that the recent quake caused less damage compared to the devastating 6.4 magnitude earthquake in December 2022. Cal Poly Humboldt Emeritus Professor of Geology, Lori Dengler explained that the location and fault movement played critical roles in the reduced impact.

The 2022 earthquake struck closer to the coast, with its rupture directly underneath the Eel River Valley—a region with soft sediment that amplified seismic waves, leading to significant destruction in towns like Rio Dell. In contrast, the recent quake occurred roughly 40 miles offshore on the Mendocino fault. Its offshore location diffused the energy, resulting in less concentrated shaking in populated areas.

“It’s not magnitude alone,” Dengler emphasized. “It’s location, geology, and the built infrastructure on top of it.”

A Reminder to Stay Prepared

Emergency preparedness expert Larry Masterman underscored the region’s good fortune, noting the earthquake’s magnitude was comparable to the deadly 1989 Loma Prieta quake, which caused extensive damage in the San Francisco Bay Area. “This was a wake-up call,” he said, urging residents to secure their homes, anchor heavy furniture, and install automatic gas shut-off valves.

Despite the minimal damage, Governor Newsom’s emergency declaration enables the rapid deployment of state resources, including the National Guard, and the use of state-owned facilities to support recovery even as the initial damage seems manageable.

Looking Ahead: It’s Not If But When

While the North Coast was fortunate this time, officials caution that the region’s seismic activity demands vigilance. Residents are encouraged to take proactive steps to prepare for the next quake. As Mattson noted, “Earthquakes can bring delayed effects, and with winter approaching, the risks could compound.”

The recent quake is a reminder of the North Coast’s vulnerability. Though this event may have spared the region, the next one might not be as forgiving.

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If you sustained damage from the December 5, 2024, earthquake, share a picture of the damage and your location in the comments.