Magnitude 5.8, 5.5 earthquakes strike off coast of Oregon

A series of earthquakes have struck off the Oregon coast but scientists say they weren't strong enough to trigger tsunamis.

The largest came first, at magnitude 5.8. It struck about midnight Sunday and was followed by three quakes early Monday. They were of magnitude 4.3, 5 and 4.4.

They struck at a fault nearly 300 miles west of Coos Bay, Oregon. They were relatively shallow, at 6 miles deep.

Scientists at the U.S. Geological Survey said it usually takes an earthquake of magnitude 7 or better to trigger a tsunami.

They say the fault that produced them generates frequent earthquakes, but it isn't the type of fault that produces the most violent quakes.