Fernbridge along State Route 211 reopens following deadly quake in Humboldt County
FERNDALE — The Fernbridge in Humboldt County reopened Wednesday night after sustaining damage in this week's deadly 6.4 magnitude earthquake.
Caltrans District 1 said there was damage to the bridge's deck and underlying structure and $6 million in emergency funding was allocated for repairs that have already begun and include repaving the road and adding additional support to the bridge's approaches.
The bridge, which is on State Route 211 over the Eel River,reopened shortly before 9 p.m. Crews will be at both ends of the bridge to ensure traffic flows smoothly. Caltrans said a structure maintenance and investigations unit determined repairs could be safely made with one-way control traffic in place.
"Thanks very much to the residents that use Fernbridge for their patience," said Tai Morgan-Marbet, Caltrans resident engineer. "Please plan extra time into your route in anticipation of delays in the area. For the first couple of days, we'll have flaggers conducting one-way traffic control, and eventually, we're looking at using a temporary signal. Please be alert and follow prompts patiently and safely."
The quake, which happened near the town of Ferndale on the Northern California coast, has killed at least two people and injured more than a dozen others.
More than 70,000 were left without power in the aftermath, but Pacific Gas and Electric said Wednesday night that restoration efforts were complete.
The big earthquake originated in an area under the Pacific Ocean where multiple tectonic plates collide, creating the state's most seismically active region.
The Mendocino Triple Junction is the meeting place of the Gorda, Pacific and North American plates, massive moving slabs of Earth's crust that are also known as lithospheric plates.
WHAT'S HAPPENING?
The small Gorda Plate — often referred to jointly with the Juan de Fuca Plate to the north — is diving under the North American plate in a process called subduction. It is part of what scientists call the Cascadia subduction zone, which stretches from Northern California into Canada.
"In this Triple Junction area, it's a complicated jigsaw puzzle," said Lori Dengler, professor emeritus of geology at Cal Poly Humboldt.
Tuesday's magnitude 6.4 earthquake occurred at 2:34 a.m. southwest of Ferndale, about 210 miles northwest of San Francisco. The quake was centered offshore and numerous aftershocks followed.
Initial analysis by the U.S. Geological Survey points to the Gorda Plate as the quake's source.
"The location, depth and faulting mechanism indicate that this event likely occurred within the subducting Gorda Plate," the USGS said.
DOES THIS HAPPEN OFTEN?
It was the latest in a long history of large quakes that have struck the lightly populated region of redwood forests and quaint Victorian homes as the plates grind against each other.
The USGS said that in the past century there have been at least 40 other earthquakes of magnitude 6 or larger, including six quakes of magnitude 7 or larger, within 155 miles of where Tuesday's quake was centered.
The quake occurred one year to the day after the nearby Dec. 20, 2021, Petrolia quake. That quake was actually two overlapping quakes of magnitudes 6.2 and 5.7, according to the USGS.
"We have hundreds of faults in the vicinity of what we call the Triple Junction," Dengler said. "It's just been sheared up. There are all sorts of pieces."
