Mother Nature rumbles

Scientists are listening to earthquakes off the Oregon coast. The earthquakes are the type that usually indicate impending volcanic activity - but there are no volcanos.

Scientists listening to underwater microphones have detected an unusual swarm of earthquakes off central Oregon, something that often happens before a volcanic eruption — except there are no volcanoes in the area.

Scientists don't know exactly what the earthquakes mean, but they could be the result of molten rock rumbling away from the recognized earthquake faults off Oregon, said Robert Dziak, a geophysicist for the National Oceanic and Atmospheric Administration and Oregon State University.

There have been more than 600 quakes over the past 10 days in a basin 150 miles southwest of Newport. The biggest was magnitude 5.4, and two others were more than magnitude 5.0, OSU reported.

On the hydrophones, the quakes sound like low thunder and are unlike anything scientists have heard in 17 years of listening, Dziak said. Some of the quakes have also been detected by earthquake instruments on land.

There's no connection, of course, but it reminded me of Mount St. Helens and the explosion in May, 1980. If there's a lesson for us: We're studying the Earth more than ever before, and the Earth just reminded us again how little we actually know.