Monday, December 29, 2008

I'm Not a Seismologist... (UPDATED)

"...but I did stay at a Holiday Inn Express last night."

Okay, so it was two weeks ago, and it was a Best Western, and I actually found out about it from the Drudge Report, but something interesting is happening in Yellowstone National Park.


From the USGS Yellowstone Volcano Observatory:
The University of Utah Seismograph Stations reports that a swarm of small earthquakes of magnitude 3.5 and smaller is occurring beneath Yellowstone Lake in Yellowstone National Park, five to nine miles south-southeast of Fishing Bridge, Wyoming. The swarm began yesterday afternoon, Dec. 26, and has continued and intensified today. The two largest earthquakes in this swarm have been shocks of magnitude 3.5 and 3.4 which occurred at 1:17 and 1:26 pm MST, respectively, today. Many smaller earthquakes have also occurred, including three events this morning of magnitude 2.5 to 2.8 and a magnitude 3.2 event at 3:30 pm MST. Some of the earthquakes in the swarm have been reported felt by people in the Yellowstone Lake area. Swarms of this nature are relatively common in this part of Yellowstone Park.

These swarms are suggestive of magma movement, but given the nature of Yellowstone Park, that's not saying much. There's lots of magma movement.

What is of interest is if this remains a trend. Sustained swarms, coupled with changing depths of the earthquakes, could suggest a volcano is developing. Right now, there is enough data to say what, if anything, is happening. But it is enough to command some attention.

Further resources:

USGS Yellowstone Volcano Observatory
University of Utah Seismograph Stations
UUSS Recent Earthquakes in Yellowstone

UPDATE, 4:00 PM:

Scientists watch unusual Yellowstone quake swarm

Scientists are closely monitoring more than 250 small earthquakes that have occurred in Yellowstone National Park since Friday.

Swarms of small earthquakes happen frequently in Yellowstone. But Robert Smith, a professor of geophysics at the University of Utah, says it's very unusual to have so many over several days.

The largest tremor was Saturday and measured magnitude 3.8.

Smith says it's hard to say what might be causing the tremors but notes that Yellowstone is very geologically active. An active volcano there last erupted 70,000 years ago.