Oregon Public Broadcasting

The Oregon coast got a jolt Monday when a 4.1 magnitude earthquake hit 100 miles off the state’s central coast.

The quake’s epicenter was six miles deep, according to the U.S. Geological Survey.

No tsunami warning was issued.

Seismologist David Oppenheimer says the quake was so small that even if it did have aftershocks, they wouldn’t be detectable.

David Oppenheimer: “This is a very typical earthquake for the Blanco Fracture Zone. Now, it’s possible to cause a small tsunami and they have been recorded, but not the kind that people worry about.”

The specific fault line is called the Blanco Fracture Zone.

Seismologists say the state’s real earthquake concern is not there – but along the Cascadia Subduction Zone, closer to the California border.