An earthquake swarm continues off the US Pacific Coast. But experts don't seem concerned

The earthquake swarm off the Oregon coast continues -- with almost 100 quakes in the past 48 hours -- but experts say not to worry.

While the major concern with big earthquakes this far from land is the possibility of tsunamis, "events the size that have so far occurred in this swarm will not generate noticeable tsunamis," writes the United States Geological Survey.

In addition, the fault line where the swarm is taking place -- the Blanco Fracture Zone -- moves side to side and isn't the type of megathrust fault that displaces ocean water to form tsunamis. Such tsunami-producing earthquakes are more common on a nearby fault line.