By Oregon Capital Chronicle staff
A strong earthquake struck off the northern California coast Thursday morning, triggering an unusual tsunami warning for northern California and southern Oregon and an evacuation of some residents and visitors there.
The National Tsunami Warning Center, which is based in Alaska, issued the warning shortly after the 7 magnitude quake hit off the northern California coast about 10:44 a.m. It hit 45 miles southwest of Eureka, which lies about 100 miles south of the Oregon border. Center officials said the earthquake was shallow – about 8 miles deep – and that a swath of the coast in the two states could be affected. In Oregon, the warning covered the area stretching from Brookings and Gold Beach to Bandon, Port Orford and north of Reedsport.
U.S. Geological Survey officials later said the earthquake was caused by horizontal movement of undersea plates, which is why a tsunami didn’t materialize. Over 13,000 people reported feeling the earthquake, with concentrations of reports in the Medford area and even further north, The Oregonian/OregonLive reported.
The general area where the earthquake occurred is known as the Mendocino Triple Junction, likely near the Mendocino Fracture Zone, according to Tim Clements, a research geophysicist with the USGS. The earthquake was not on the Cascadia Subduction zone, he added, but it was near it.
Tsunami warning center officials said they had no reports of any immediate damage and lifted the warning just before noon, but by that time at least some people had already been evacuated.
Brookings police started to evacuate residents close to shore to higher ground in anticipation of the tsunami hitting around 11:24 a.m., an emergency responder told the Capital Chronicle.
Curry County Emergency Manager Jeff Hughes directed police and firefighters in Gold Beach to turn on two manually-operated warning sirens and tell everyone to evacuate immediately.
“We didn’t actually physically go in and start removing people,” Hughes said.
There wasn’t enough time to do more than send out a countywide evacuation order and get emergency responders to warn people in low-lying areas near the water, he said
“Whoever heard it and heeded it, went to high ground,” he said. As of midday, there were no reports of property damage or injuries, Hughes said.
“It’s a good run for folks who are paying attention, who are actually subscribed to the notification systems and are actually prepared for circumstance. There’s a vast number of people who are not, or were not, and I cannot emphasize enough, if you live on the coast, to be prepared for circumstances like this,” Hughes said.
All state park beaches were closed after the first warning Thursday until reopening abut 3 p.m. by the Oregon Parks and Recreation Department.
Andy Bryant, a hydrologist with the National Weather Service in Portland, said typically it takes about 45 minutes to an hour for a quake to trigger a tsunami and that usually the waves come in succession. He also said the fact that the quake was centered off Eureka and not the Oregon coast meant that waves would be traveling northward.
“It’s not like the waves would be coming in perpendicular to the coast,” Bryant said. “That likely will reduce the impact.”
Outside the immediate warning area, Lane County sent out a notification to inform coastal area residents that they could seek higher ground if they were concerned, said Devon Ashbridge, public information officer for Lane County.
“While it wasn’t expected that Florence would be directly impacted, we wanted them to be aware of that to make the best decision they can for their safety,” Ashbridge said.
The initial warning went right up to the county line between Douglas and Lane counties, about 10 miles from Florence. The county put out a similar alert in 2022 during an earthquake in the South Pacific, Ashbridge said.
While the alert was limited to coastal and surrounding areas, not countywide, it went to more than 22,000 contacts, Ashbridge said. Some of those, however, are duplicates because people can sign up to receive alerts by automatic phone calls, texts or emails.
“We’re of course incredibly grateful that this didn’t cause a tsunami, but we know the possibility is out there,” she said. “So these moments of panic are a good reminder to prepare.”
Lincoln County emergency managers sent a tsunami warning to the 12,140 subscribers who signed up for its alert system.
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