A swarm of earthquakes has been rattling the ocean off the coast of Oregon over the past 24 hours. Officials have reported over 50 quakes, between 200 and 300 miles off the coast of Newport, though none of them were felt on land, and there were no reports of damage or injuries.
The quakes occurred on the Blanco Fracture Zone fault line, which is one of the most active in the United States. According to CNN, the fault line has produced over 1,500 quakes with a magnitude over 4.0 since the 1970s, making it more active than the San Andreas Fault in California.
The quakes were relatively shallow and ranged in magnitudes between 3.8 and 5.8. Nine of the earthquakes had a magnitude above 5.0.
There were no reports of tsunamis as a result of the earthquakes.
"Blanco Fracture zone quakes are strike-slip (lateral motions of the crustal blocks on either side, rather than up-down displacement), so it is very unlikely for them to pose a tsunami threat, even if a bigger quake happened, like a magnitude 7.0, for example," Harold Tobin, Director of the Pacific Northwest Seismic Network at the University of Washington, told CNN.
Tobin said it is unlikely that the recent swarm of earthquakes is a precursor to a bigger one.
"Today's quakes can be thought of as something like a main-shock and a swarm of aftershocks, the one distinction being that in this case, there's not a lot of magnitude difference among them," he explained.