The U.S. Geological Survey says a magnitude 5.9 earthquake struck just over 100 miles off the Oregon coast in the Pacific Ocean just before 7 am local time Saturday morning. The tremor was centered about 300 miles southwest of Portland.
The earthquake formed near a convergent plate boundary where two of earth's tectonic plates come together, and one plate is forced upward as the other slides beneath it. Such tectonic plate boundaries, or faults, are often the site of some of the largest tsunami-producing earthquakes including the large earthquake that produced the deadly tsunami in December 2004 in the Indian Ocean.
The West Coast and Alaska Tsunami Warning Center says the Saturday morning Pacific quake was likely not strong enough to produce a major tsunami, however underwater landslides that may be caused by the earthquake could produce enhanced waves along the United States Pacific Coast.
No damage has been reported.