Swarm of more than 50 earthquakes rattles off the Oregon coast, geologists say

At least 50 earthquakes have rattled off the Oregon coast in the past 24 hours, geologists said.

The earthquake swarm of dozens of earthquakes was reported Tuesday, Dec. 7, into Wednesday morning, according to the U.S. Geological Survey.

The swarm included two 5.8 magnitude earthquakes and dozens more quakes bigger than 3.4 magnitude, USGS reported.

The earthquake activity off the Oregon coast isn’t uncommon, experts said. In the past five years, there have been nearly 50 earthquakes above 4.5 magnitude, according to the Pacific Northwest Seismic Network.

“The activity off the coast of Oregon is certainly eye-catching, but nothing to be extra concerned about,” experts said. “This area, called the Blanco Fracture Zone, is very active.”

There is no tsunami risk from the earthquake swarm, according to the National Weather Service. Some water may be displaced, but the earthquakes happened far from the shoreline and along faults.

Since the earthquakes happened so far from shore, few people reported feeling any shaking, according to USGS.

Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says. It replaces the old Richter scale.

Quakes between 2.5 and 5.4 magnitude are often felt but rarely cause much damage, according to Michigan Tech.

This story was originally published December 8, 2021 at 6:27 AM with the headline "Swarm of more than 50 earthquakes rattles off the Oregon coast, geologists say."