EON

Swarm Of Small Quakes Mystify Experts

Newport – One of the more pristine area of the Pacific Northwest, the Oregon Coast has long been known for its quiet Pacific charm. But much of that charm is caught up in mystery.

What is causing the rash of earthquakes that is being experienced?

There have been nearly 600 small earthquakes in a region of about 350 kilometres off the coast of Yachats. These earthquakes have been small, registering about 2 or 3 on the magnitude scale, but a few of them have been larger, registering 4 or 5.

These quakes have posed no threat, as they have not caused any rapid water movement nor have they posed any danger to coastal residents. The quakes are coming from the middle of a magma plate, the Juan de Fuca tectonic plate. This is unusual because most of the time the action of plates rubbing against each other is what causes earthquakes.

The Pacific plate, for example, grinds against the southern edge of the Juan de Fuca plate at the famous San Andreas Fault in California. That is where most of the earthquakes in the Pacific Region normally come from, not from the middle of a plate.

Swarms of earthquakes of this nature tend to indicate volcanic activity, But much has to be learned about how plate tectonics affect the earth, and these earthquakes may be one element of that learning.