Preliminary reports from the United States Geological Survey show the agency registered a 6.0 magnitude earthquake off the shore of Oregon on Tuesday evening in the Pacific Ocean. This earthquake struck at 7:31 p.m. local time. The West Coast and Alaska Tsunami Warning Center issued an alert that a tsunami was not expected with this earthquake.
This quake was at a shallow depth of 6.2 miles and was located along the Blanco Fault of the Juan de Fuca plate -- about 159 miles west of Coos Bay, Oregon. This earthquake comes one day after a 5.6 magnitude quake rattled northern California near the Pacific Coast. A 4.2 magnitude earthquake struck off the coast of Vancouver Island toward the northern edge of the Juan de Fuca plate earlier in the day on February 14 at 2:54 p.m. local time.
The Juan de Fuca plate is a small plate located along the Cascadia Subduction Zone in the Pacific Northwest. The Cascadia zone features both seismic and volcanic activity as the Juan de Fuca plate moves eastward and tries to subduct -- or slide underneath -- the westward drifting North American plate. This earthquake was located along plate boundaries, which is where most earthquakes occur -- unlike the New Madrid Seismic Zone that is located just south of southern Illinois.
New Madrid and other fault zones within the interior of North America are not a result of plate boundaries shifting, converging, diverging, or subducting. As with the case of New Madrid, seismic activity in that region occurs due to an ancient failed rift that occurred when the North American continent attempted to pull apart but failed. This is know as the Reelfoot Rift which is part of the New Madrid Seismic Zone.
As with any earthquake, planning ahead and being prepared is the only defense. The Earth can shake at any time without warning and while the Cascadia Subduction Zone sees numerous small earthquakes on a regular basis, New Madrid and adjacent seismic regions that cover southern Illinois (such as the Wabash Valley) experience very small earthquakes in very limited numbers. That could change at any time -- and the 6.0 magnitude temblor off the coast of Oregon on Tuesday is a perfect example of this.
Comments