Mentasta

Location - Mentasta Lake

The Mentasta School ALISON observatory was located on Mentasta Lake at 62° 55.588'N, 143° 46.835'W according to our GPS unit. A moderately large body of water roughly 4 km2 in area in the Alaska Range about 50 miles southwest of Tok, Mentasta Lake was a very scenic location for an ALISON study site.

A satellite view of Mentasta Lake (right). The village of Mentasta is light colored area on the west side of the lake. The light linear feature is the road.

Kim stands in front of two ice thickness gauges on Mentasta Lake.

The study site on Mentasta Lake is a short distance offshore from Benny Funk’s cabin.

People

Measurements at the Mentasta observatory were made by Barb Dalke and her high school students. A total of 42 students of all grades are enrolled at Mentasta School, where Barb is also the principal. Barb has been teaching at Mentasta for ten years. Prior to that she taught at the Alcan border post school, and at Tok before that. She has also taught at Kaltag. Barb has taken the GLOBE training course and is a participant in the UAF-based Observing Locally-Connecting Globally GLOBE program.

Barb (front, right), Kim (yellow vest) and the Mentasta School students who monitor the Mentasta Lake ALISON observatory.

The village of Mentasta (population ~ 150) and Mentasta Lake lie directly above the Denali Fault, which ruptured on 3 November 2002, causing a magnitude 7.9 earthquake. The earthquake caused a tremendous displacement of the water in the lake, known as a seiche (a local man, Benny Funk, said it resembled a tsunami, which is not unreasonable), that broke up the ice cover and shoved large amounts of ice up on the shore.

The RADARSAT satellite radar image sub-scenes show the lake ice before (left, 26 October 2002) and after (right, 12 November 2002) the earthquake. Before the earthquake the ice appeared dark because it was smooth and reflected most of the radar signal away from the antenna. After the earthquake the ice appeared brighter because of scattering off the rough surface and greater signal return to the antenna. Note also that the outline of the lake was greatly obscured after the earthquake due to scattering from the rough ice that was thrown up on the shore.

The original radar images were obtained from the Alaska Satellite Facility at the University of Alaska Fairbanks and are copyrighted by the Canadian Space Agency (CSA). The white O marks the location of the ALISON observatory.

Data

Download data for these graphs and other ALISON data.