A swarm of small to medium earthquakes rattled the seafloor off the coast of Oregon overnight and into Monday afternoon. The latest one was a 5.9 Richter in the same area as the other four, 250 miles off Newport. They were fairly shallow – not of the variety that is usually associated with a major movement of the Cascadia Subduction Zone. None of the five produced a tsunami.
The shakers are fairly shallow as earthquakes go which indicates earth movement not directly connected with the Cascadia Subduction Zone east of this location. The area of these recent quakes is actually headed west while the Juan de Fuca plate is diving under the North American plate off the coast. Geologists say there’s still mountains of research to get through before they understand more about the relationship, if any, between the two geologic phenomenon.