Geologists record 38 small quakes on Mt. Hood since Sunday

An example of an earthquake seismograph readout.


by Keely Chalmers, KGW News

Posted on March 28, 2014 at 2:34 PM

Updated Friday, Mar 28 at 3:18 PM

A swarm of small earthquakes on Mount Hood has captured the attention of state geologists and rattled the nerves of some nearby residents.

The quakes started Sunday evening and have been rumbling directly beneath Government Camp. Rachael Fisher lives there and recently felt some unusual shaking.

“Yeah I did think I felt something up at the Palmer Lodge just up the road... yeah I think I may have felt something,” she explained.

As of Friday geologists have recorded 38 tremors. The largest one was only a magnitude 2.3, barely big enough to feel.

More: State urges preparedness after two West Coast tremors

But it's not the size of the quakes that's intriguing the scientists, it's where they're happening. They seem to be occurring right alongside a recently discovered fault.

“The fact that the earthquakes are defining a fault means that that fault is active and if it can make a magnitude 2.3 it can probably make a much larger earthquake,” explained Ian Madin Chief Scientist with the Oregon Department of Geology and Mineral Industries.

Madin has been tracking this swarm since it began.

Unlike past seismic swarms on Mount Hood, he said this one is likely not tied to any volcanic activity.

And he does not think the quakes are a pre-cursor to a future eruption.

But he explained now that geologists know there may be active fault close to Government Camp, they can keep a closer eye on it.