Mount Edgecumbe, as seen from Thomsen Harbor, Sitka, Alaska; Photo credit:U.S. Forest Service/Jeffrey Wickett
Last April, a series of earthquakes around and under Mount Edgecumbe brought greater attention to what was considered a dormant volcano. Measurements show that magma is moving deep underneath Edgecumbe. Other signs have also brought new scrutiny: Hikers have discovered vents with bubbling gas near the volcano, and satellite images show a bulging of the ground around Edgecumbe.
None of this means that Edgecumbe will blow anytime soon, but the State of Alaska has reclassified Mount Edgecumbe as a “high risk volcano”. With 73,000 people living in the region, the reclassification was probably wise. Currently, the east side of Edgecumbe is bulging faster than any volcano in Alaska.
The Alaska Volcano Observatory has plans to install seismic sensors and other instruments on Mount Edgecumbe over the coming months. Core samples show that the volcano erupted between 4000 -4300 years ago, and Tlingit oral history tells of an eruption approximately 800 years ago.
Currently, Alaska has one volcano at Code Orange, and four others at Code Yellow.
Unrest under Mount Edgecumbe and a bulging eastern flank
The storm that took over the Alaskan skies last night was pretty impressive. The entire sky lit up to the point that the snow on the ground glowed green.
I heard that last night’s magnetic storm was rated a Kp7. The Kp index rates the magnitude of a geomagnetic disturbance. A 0, 1 or 2 is considered “Quiet”. A Kp3 is “Unsettled”. Kp4 = “Active”. Kp5 is a “Minor Storm” G1. Kp6 is a “Moderate Storm” G2, while last night’s Kp7 is considered a “Strong Storm” G3. Kp8 and Kp9 top the index as “Severe Storm” G4 and “Extreme Storm” G5, respectively.
There are some really incredible images out there online from last night’s Strong Storm. The two here are only cell phone images, and they do not do the aurora justice. It was really a phenomenal show. As you can see, we were not limited to just the green northern lights, but quite a bit of red was visible to the naked eye.
The skies were crystal clear, as expected, with temps dipping down to -32F at the cabin. I can’t wait to see if we get a second round tonight.
A magnetic storm is headed our way from the sun, which should offer great aurora viewing Sunday and Monday. Hopefully the clear skies hang around tonight. With a forecast of -20F, I am assuming we will have the all clear for the aurora.
The Nenana Basin lies southwest of Fairbanks. The Parks Highway runs along its eastern boundary, and the Tanana River runs right through the middle of it. The basin is 56 miles long and 7.5 miles wide. Over the course of millions of years, the basin has been filled in with river sediment. Considering that the basin is 4 miles deep (7km), that is a lot of fill.
Several entities have been drilling test holes throughout the basin looking for oil and gas, so the University of Alaska – Fairbanks has been studying the basin’s makeup. One thing they found is that earthquakes last longer and feel a lot stronger in the basin, than just outside the basin.
The shockwaves from an earthquake travel differently through the sediment, which is mostly gravel, than the solid rock along the ridge lines. Reverberation also plays a roll here: The seismic waves are amplified by the basin walls and floor.
Seismic sensors have verified what local residents have been claiming: The shaking is a lot worse down in The Flats than up in the hills.
Source credit: Alaska Public Media, University of Alaska – Fairbanks
There is a cluster of volcanic islands in the Aleutian Chain that scientists have recently been asking a rather provocative question: Could they all be a part of one giant super volcano, similar to the Yellowstone Caldera?
This tight grouping of islands is home to six stratovolcanoes: Carlisle, Cleveland, Herbert, Kagamil, Tana and Uliaga. Mount Cleveland has been one of the most active volcanoes in North America over the past 20 years.
Most stratovolcanoes tend to have modest sized reservoirs of magma. Although that doesn’t mean they can’t have explosive eruptions, but they are dwarfed by caldera forming eruptions. A caldera is formed by tapping a huge reservoir of magma in the earth’s crust. A caldera forming eruption releases a massive amount of lava and ash, and they are catastrophic, often causing world-wide effects.*
Field work continues, although there is nothing easy about doing research in the Aleutians.
Mount Cleveland
Photo and map credit: USGS, *University of Alaska – Fairbanks
It’s the tail end of Volcano Week with the National Park Service. The above photo, of Mount Wrangell, was taken in 1902 by W.C. Mendenhall, of the U. S. Geological Survey. The namesake of Mendenhall Glacier.
Mount Wrangell is a andesitic shield volcano within Wrangell-St Elias National Park. Its last eruption was in 1930, but it has been actively steaming for over 100 years.
The Yukon Quest Sled Dog Race starts on Saturday morning from downtown Fairbanks. The race, 550 miles long, is roughly half the distance from what it was pre-pandemic. Gone is the international flavor of the race, with Alaska and The Yukon going their separate ways.
In addition to the 550, there will also be a 300 mile run and an 80 mile youth mush.
Only time will tell if the race can survive without the international aspect of the Whitehorse – Fairbanks cooperation.
