The Shishaldin Volcano on Unimak Island; Photo credit: USGS
Mount Shishaldin, which is one of the most beautiful and perfectly cone-shaped volcanos on the Aleutian Chain, has been restless since July 2019, with several short burst eruptions. At the end of December, temperature elevations were measured at its summit, and seismic activity had increased substantially.
This past Friday morning, Shishaldin erupted, sending ash five miles into the air. Volcanic lightning, and the glow of lava near the summit, could be seen from Cold Bay.
Shishaldin from high; Photo credit: AVO
At an elevation of 9373′, Mount Shishaldin is the highest peak in the Aleutians. Shishaldin is relatively young, with its cone less than 10,000 years old, although remnants of an ancestral volcano can be found on Unimak.
Mount Shishaldin, postcard image, circa 1910; Photo credit: J.E. Thwaites
The first known ascent of Shishaldin happened in 1932, when G. Peterson and two others, made the climb to the summit. It is widely understood, that native Aleuts and visiting Russians certainly made the climb previously, but their ascents were not documented.
Local climbers are known to still make the climb to Shishaldin’s summit, then ski back down its flank.
Mount Veniaminof letting off some steam, 25 September 2018; Photo credit: AVO/Mari Peterson
Mount Veniaminof, the glacier covered volcano on the Alaska Peninsula, has been erupting since early September. The Alaska Volcano Observatory reports that lava is still flowing from the caldera this week. The volcano last erupted in 2013.
ESA Sentinel-2 image of Veniaminof, showing lava flow on the south flank of the volcano. Photo credit: AVO/USGS
Veniaminof sent a plume of ash, 13,000′ into the air in late November, but that action has come to a stop, at least for now.
Currently joining Veniaminof on AVO’s Orange Alert List, is the seemingly always active Mount Cleveland.
Mount Cleveland from Concord Point; Photo credit: AVO/USGS/John Lyons photographer
Lava flow was seen in the crater of Mount Cleveland this week, about 80 meters across. With lava flowing over the active vent, the odds of an explosion to clear that vent has increased substantially. With that in mind, the warning level on Cleveland was raised to Orange.
Great Sitkin Volcano on 17 June 2018; Photo credit: AVO/Alaska Airlines Captain Dave Clum
Great Sitkin Volcano, also on the Aleutian Chain, which had a minor eruption on June 10th, is still smoking. AVO has Great Sitkin’s warning level at Yellow.
Novarupta, still steaming in 1923, 11 years after its eruption. Photo courtesy: Katmai NP&P
On 6 June 1912, Novarupta, located in the Aleutian Range, erupted. The 60 hour eruption would end up being the most powerful volcanic event of the 20th Century.
The people in Juneau, Alaska, 750 miles away, heard the blast from the eruption an hour after it occurred. In the end, 30 cubic kilometers of ejecta blanketed the area. That was 30 times more than the 1980 eruption of Mount St Helens; 3 times more than the second largest eruption of the century from Mount Pinatubo; and more ejecta than all of Alaska’s historic eruptions combined. The ash fall was so heavy, that roofs on buildings on Kodiak island collapsed from the weight.
The pyroclastic flow from Novarupta, filled 20 km of the valley of Knife Creek, turning the v-shaped valley into a wide, flat plain. When it was over, the pyroclastic flow would solidify into an area 120 square kilometers at depths of over 200 meters.
Katmai Caldera, photo credit: USGS
So much magma was expended during the eruption, that the peak of Mount Katmai, which lies 6 miles from Novarupta, collapsed, leaving a two mile wide by 800 foot deep crater. Early investigations had Katmai as the source of the massive eruption.
Novarupta lava dome, photo credit: USGS
It wasn’t until the 1950’s, when investigators realized that Novarupta was responsible for the eruption, and not Katmai.
In 1916, the National Geographic Society sent an expedition to Alaska’s Katmai area. Led by Robert Griggs, it was Griggs who named the former valley of Knife Creek, “The Valley of 10,000 Smokes”.
“Having reached the summit of Katmai Pass, the Valley of Ten Thousand Smokes spreads out before one with no part of the view obstructed. My first thought was: We have reached the modern inferno. I was horrified, and yet, curiosity to see all at close range captivated me. Although sure that at almost every step I would sink beneath the earth’s crust into a chasm intensely hot, I pushed on as soon as I found myself safely over a particularly dangerous-appearing area. I didn’t like it, and yet I did.” — James Hine, Zoologist, 1916 Griggs Expedition *
Bogoslof volcano, as seen from a satellite image, 18 minutes after the start of the eruption 5.28.17
Bogoslof once again went red on Monday morning at 10am. The ash plume extended to 32,000′. The ash cloud from the above photo, from a May eruption, rose to over 40,000′. Since December, Bogoslof has erupted 60 times.
Bogoslof’s eruption of 23 December 2016. Photo credit: Crew of USCG Cutter Alex Haley
With Bogoslof being as active as it has been recently, there has been an increase in interest regarding Alaska’s many volcanoes. Since mid December, Bogoslof has erupted ten times.
Plume from the eruption of Bogoslof on 20 December. Photo credit: Paul Tuvman/AVO
According to Alaska Volcano Observatory, which is a joint program by the U.S. Geological Survey and the University of Alaska – Fairbanks, Alaska has 90 volcanoes that have erupted in the past 10,000 years – and could erupt again. Of those 90, 50 have erupted since records started being kept in 1760.
Unlike volcanoes in Hawaii, which tend to ooze lava, Alaska volcanoes usually explode, sending ash as high as 50,000 feet in the air. Airlines get anxious when ash gets above 20,000 feet, and Bogoslof has consistently sent plumes into the 35,000′ range.
FAA estimates that roughly 80,000 large aircraft fly downwind of the Aleutian volcanoes yearly, with 30,000 people doing so every day. When Redoubt erupted in 1989, a KLM jet, which was 150 miles away, flew through Redoubt’s ash path. The jet lost all four engines with 231 people on board. The aircraft had dropped two miles, down to just over 13,000 feet, when the crew managed to restart the engines, and safely land in Anchorage.
Changes in Bogoslof Island with the recent eruptions. Credit: USGS/AVO
Photos and statistics come courtesy of AVO and their website. A special shoutout to the USCG Cutter Alex Haley: Nice photo, I hope its inclusion in the post is acceptable.
The submarine volcano at Bogoslof Island in the Aleutian Chain has gone Red twice in two days. An ash plume was sent up 34,000 feet on Wednesday, causing some concern for passing aircraft.
Bogoslof Island was first mapped after it’s eruption in 1796. The 173 acre island has seen six eruptions since then, from various vents. The island rises to 490′ above sea level, but approximately 6000′ from the seabed.
Castle Rock on Bogoslof Island; Photo credit: Ann Harding/AVO
“Castle Rock”, as seen above, is the eroded remnant of a dome from the 1796 eruption. Currently, AVO has downgraded the alert level to Orange.
Brown bears fishing at Brooks Falls in Katmai National Park
The Katmai National Park Bear Cam is back up and running for the season. The camera overlooks Brooks Falls in the park, where the bears congregate to fish the salmon run.
The 6395 square mile park was established as a National Monument in 1918. Located on the Pacific side of the Alaska Peninsula, Katmai is home to approximately 2200 brown bears. It is considered to be one of the Seven Wildlife Wonders of the World.
The Bear Cam has once again been set up by explore.org. The link is below.