The National Weather Service reported that there were more than 50 earthquakes in less than 24 hours off the coast of Oregon.
The strongest of the earthquakes had a magnitude of 5.8 and caused slight damage to buildings. The US Geological Survey said the earthquakes were too far out to be felt on land.
Experts say that a swarm of earthquakes isn't inherently dangerous.
The director of the Pacific Northwest Seismic Network and professor of earth and space sciences at the University of Washington told The Seattle Times that this is not cause for alarm.
The NWS wrote on the social networking site that swarms are common. They occur far from shore along strike-slip faults. There is no risk of a disaster because there is little water displaced.
Strike-slip faults are similar to thrust faults, in that rock mass slide alongside one another, and are more likely to produce more powerful earthquakes.
The Fracture Zone of the Blanco is seismoically active.
Over the past five years, there have been 49 earthquakes above a 4.5 magnitude in the area west of Newport, Oregon.
"This is perhaps the most active fault in North America," said Tobin.
The BFZ produces destructive earthquakes.
The Cascadia Subduction Zone, where the bulk of powerful earthquakes in the northwest have historically taken place, has the potential to generate a 9.0-magnitude earthquake according to the Oregon Office of Emergency Management. A 100 feet high wave could hit the coast as the earthquake moved inland, but it could be dissipated as it moved inland.
The New Yorker reported in 2015 that FEMA had projected that there would be over 20,000 deaths and over 30,000 injuries in a Cascadia earthquake.
There is a one in three chance of that happening in the next five decades.
Experts say that BFZ earthquakes are unrelated to the threat.
The big fault under land won't be affected by the Blanco Fracture Zone because it isn't connected to the subduction zone.
Five magnitude 5 earthquakes in an hour is impressive, but not a concern as this is far from the Cascadia subduction zone.
