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United States: Swarm of more than 40 earthquakes rattle off the coast of Oregon

One of North America’s most active fault lines sprung to life on Tuesday after a swarm of more than 40 earthquakes ranging from a magnitude 3.5 to 5.8 rattled off the coast of Oregon, catching the attention and concern of millions in the region.

The series of quakes, which began early Tuesday morning and continued into Wednesday, were all clustered between 200-250 miles west of the coastal town of Newport, Oregon, far enough to be mostly undetected on land, but given the area’s seismic history, it is creating quite a buzz.

“If you had asked me yesterday where on Earth would be most likely to produce a bunch of magnitude 5.0+ quakes in a single day, this would have been high on my list,” Harold Tobin, Director of the Pacific Northwest Seismic Network at the University of Washington said.




The fault line responsible for the quakes is the Blanco Fracture Zone. According to an analysis by Oregon State University, it is more active than the infamous San Andreas Fault in California, having produced more than 1,500 quakes of magnitude 4.0 or greater since the 1970s.

What has been most impressive about this week’s quakes is the swarm has included at least 9 tremors reaching a magnitude 5.0 to 5.8, with the majority occurring at a shallow depth of only 10 km.

The sheer number of magnitude 5.0 or greater quakes in the region triples the annual average since 1980, according to the USGS database.



According to seismologist Dr. Lucy Jones, there have been more than 133 quakes of magnitude 5 or greater on the Blanco Fracture Zone since 1980 and have never been followed by something on land.

However, this week’s quakes have raised the concerns that a so-called “big one” could be near.