The excitement is over for now for scientists at the Yellowstone Volcano Observatory as a larger than normal swarm of earthquakes ended under the northern part of Yellowstone Lake at the Yellowstone National Park in Wyomying.

Seismologists at the YVO say that between December 26 of last year until January 8, 2009, Yellowstone experienced approximately 900 seismic events with magnitudes up to 3.9 on the Richter scale. After January 8, the seismic activity dramatically decrease in the park.

Scientists are quick to point out that earthquake swarms are a common occurrence in Yellowstone but they normally do not happen in this quantity. Yellowstone had 315 quakes for the month of January. 205 were associated with the swarm under Yellowstone Lake.

Yellowstone is situatied on top of a volcano that last erupted over 70,000 years ago.

This swarm is the second largest on record. A swarm of quakes in 1985 is the largest. Records of quake activity at Yellowstone have only been kept since 1973

Experts at the YVO say there are several common causes for earthquake activity at Yellowstone. One such cause are the stresses that occur below ground from the nearby Teton and Hebgen Lake faults.

At this time, none of the hot springs at Yellowstone seem to be affected from the extra seismic activity.

Sources:
Yellowstone Volcano Observatory
The Denver Post

This camera is located approximately 7.5 miles (12 km) from Redoubt’s summit crater..

On January 23, Mount Redoubt began showing increased volcanic activity. Since then, scientists at The Alaska Volcano Observatory have been staffed 24 hours a day monitoring the 10,197 foot peak’s activity.

Research geophysicist Peter Cervelli, with the observatory says “we expect based on the past behavior of this volcano that this activity is going to culminate in an eruption.”

The observatory has now put the mountain, which is located 100 miles southwest of Anchorage, Alaska, on code level Orange-Watch, the second highest level. This level is given when, “a Volcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain or an eruption is underway that poses limited hazards including no or minor volcanic-ash emissions.” This is according to the U.S. Geological Survey.

The A.V.O. says the biggest concern about an eruption is what ash in the air could do to air traffic. Michelle Coobes, a geologist at the A.V.O stated, “once that silica-rich ash gets ingested into the engine, it can remelt and coat the insides of the engines and freeze up those engines.”

In 1989, a Boeing 747 airliner flew through an ash cloud a day after Mount Redoubt erupted. This caused all four engines of the plane to stall. Luckily the pilot was able to get two of the engines restarted and the plane landed safely in Anchorage.

As a precaution, approximately 200 pilots and mechanics as well as their planes are being moved from Elmendorf Air Force Base in Alaska to McChord Airforce Base in Washington State.

December 1989 was the last time Mount Redoubt erupted. The event lasted until April of the following year.

A webcam of the peak can be seen at the top of this story.

The Alaska Volcano Observatory has set up a Twitter feed for those who want to keep up with this story.

Sources:
Alaska Volcano Observatory
CNN.com-Reference 1
CNN.com-Reference 2
MSNBC.com