Over 50 earthquakes have been recorded off the Oregon coast in the past 24 hours.
According to the U.S. Geological Survey’s website, a total of 56 earthquakes have been recorded off the coast of Oregon between Dec. 7 and Dec. 8, with the largest two quakes reaching magnitude-5.8.
All the earthquakes were recorded about 10 kilometres below the surface.
The earthquakes have been occurring about 320 kilometres (200 miles) to 400 kilometres (250 miles) west of Newport, Ore., in an area called the Blanco Fracture Zone.
The Pacific Northwest Seismic Network, which monitors earthquakes and volcanoes in Washington and Oregon, said on social media Wednesday that the “swarm” of earthquakes, while interesting, isn’t overly concerning because they are too far away from the Cascadia Subduction Zone.
“These are too small and far away from Cascadia (CSZ) to affect it. These relatively small transform faulting (side-to-side motion) events don’t generate tsunamis,” the network said in a series of tweets.
PNSN, which also lists the number of recorded earthquakes at 58, called the Blanco Fracture Zone one of the most seismically active areas in North America, even more so than the San Andreas.
Over the last day and a half there has been a swarm of 58 M3.5-5.8 earthquakes on the Blanco Fracture Zone (BFZ). These are too small and far away from Cascadia (CSZ) to affect it. These relatively small transform faulting (side-to-side motion) events don’t generate tsunamis. pic.twitter.com/9exgtAOf7n
— PNSN (@PNSN1) December 8, 2021
The Blanco Fracture Zone is one of the most seismically active areas in North America, even more so than the San Andreas. Even for this area, there have been an unusual number of EQs larger than M5 in this swarm. This is interesting, but let’s talk about why it isn’t concerning. pic.twitter.com/51r1wWJCvQ
— PNSN (@PNSN1) December 8, 2021
It is also very unlikely for the EQs in this swarm to cause a tsunami. These EQs are strike-slip, meaning the crustal blocks on either side of the fault slide past each other. This does not result in a significant vertical displacement of water, and thus does not cause a tsunami.
— PNSN (@PNSN1) December 8, 2021
With files from The Associated Press