Earthquake strikes off Northern California near Oregon border; tsunami warnings canceled

The National Weather Service canceled its tsunami warning for the U.S. West Coast after a powerful earthquake shook parts of California on Thursday.

At least 5.3 million people in California were under a tsunami warning after the 7.0-magnitude temblor, the U.S. Geological Survey said in a yellow alert, which predicted localized but minimal damage. The quake was felt as far south as San Francisco, where residents felt a rolling motion for several seconds. It was followed by smaller aftershocks.

There were no immediate reports of major damage or injury.

The quake struck at 10:44 a.m. west of Ferndale, a small city in coastal Humboldt County near the Oregon border, according to the USGS.

“It’s not surprising to have earthquakes in this area,” Christine Goule, director for the USGS Earthquake Center in San Francisco, said at a news conference. “There are three tectonic plates in the region. There is a 40% chance of aftershocks of 5.0 or lower over the next week.”

It was felt as far south as San Francisco, where residents felt a rolling motion for several seconds. It was followed by smaller aftershocks.

The San Francisco Bay Area Rapid Transit District, known as BART, has returned to operations after a short stoppage.

Earthquake tracker: The latest earthquakes recorded in the PNW

The San Francisco Zoo’s visitors have been evacuated as a result of the earthquake, the zoo said in a post on the social media platform X. The animals have been secured and staff has been moved to higher ground.

Throughout Northern California phones buzzed with a tsunami warning from the National Weather Service that said: “A series of powerful waves and strong currents may impact coasts near you. You are in danger. Get away from coastal waters. Move to high ground or inland now. Keep away from the coast until local officials say it is safe to return.”

The National Weather Service’s U.S. Tsunami Warning System reported Thursday afternoon that after earlier tsunami warnings and watches had been issued for the three U.S. West Coast states had been canceled.

The tsunami Warning is canceled for the coastal areas of California and Oregon. No tsunami danger presently exists for this area. This will be the final U.S. National Tsunami Warning Center message for this event. Refer to https://t.co/npoUHxX900 for more information.

— NWS Tsunami Alerts (@NWS_NTWC) December 5, 2024

As part of its coverage of this earthquake and subsequent tsunami warning, The Associated Press compiled a list of facts to consider about tsunamis:

What is a tsunami?

A tsunami, a word that comes from the Japanese characters for harbor and wave, is a series of extremely long waves caused by the sudden displacement of the ocean, according to the National Weather Service.

“Most tsunamis, and the largest, result from earthquakes on reverse faults. These tsunami-generating earthquakes originate mainly in subduction zones, where tectonic plates collide and one is forced under the other,” the National Oceanic and Atmospheric Administration said.

If this is large enough and closer to the ocean floor, the energy from the earthquake can cause the ocean floor to suddenly rise or fall. “This sudden vertical displacement of the ocean floor is what typically sets a tsunami in motion,” NOAA said.

“Tsunamis radiate outward in all directions from the point of origin and can move across entire ocean basins,” the service says.

When the waves reach land, they can cause coastal flooding, and the powerful currents can last several hours or days.

The weather service calls a tsunami as “one of the most powerful and destructive natural forces.”

How often to they happen?

Tsunamis that cause damage or death near earthquakes occur about two times a year, according to the Global Historical Tsunami Database.

A tsunami racing across an ocean and causing damage or deaths more than 620 miles (1,000 kilometers) away happens about twice a decade.

Where do they occur?

Tsunamis can occur in any ocean, sea or large body of water. But certain areas are prone to tsunamis because of their proximity to the source and other factors, such as depth and the shape of the ocean floor.

The database says between 1900 and 2015, there were 754 confirmed events. Of those, 78% were in the Pacific Ocean. According to the database, Japan has had the most tsunamis since 1900, followed by Russia and Indonesia.

A magnitude 9.2 temblor, the second most powerful earthquake ever recorded globally, caused widespread damage in the Anchorage area in 1964 and killed 131 people, including some in Oregon and California by the ensuing tsunami.

Most destructive tsunamis

In 2004, a magnitude 9.1 earthquake occurred off Sumatra, an Indonesian island in the Indian Ocean. It generated a tsunami that was as high as 167 feet (51 meters), causing an estimated 230,000 deaths.

Another magnitude 9.1 earthquake struck in Japan in 2011, creating a tsunami with waves reaching 1,272 feet (39 meters). The tsunami caused about 18,000 deaths and prompted a nuclear power plant accident.

Contributing: The Associated Press; Steve Coogan and Bill Kaczaraba, MyNorthwest