Tag Archives: volcano

Atka Volcanic Complex

Earthquake activity on Atka Island

The southern portion of Atka Island is older than the north, with some volcanic rock dating back 5 million years. The active northern part of the island once had one large cone, which was lost in a large eruption, and is now peppered with several smaller volcanos.

A volcanic complex can have several vents, and a widely varying composition of lava. Seismic activity within a complex can be difficult to pinpoint the source of the activity. Which vent is rumbling now? Some of those smaller vents have developed into stratovolcanoes.

Korovin Volcano has been very active in recent times, while Mount Kliuchef last erupted in 1812. The Atka Complex recently was elevated to a Level Yellow, due to seismic activity on the island. Interestingly, the swarm of activity is not near the known suspects, but several kilometers the the west and southwest, and approximately 10 miles from the community of Atka.

Source: AVO


Great Sitkin & other rumblings

The growing lava dome on Great Sitkin; Photo credit: AVO/Dave Ward (8/4/21)

I had to share this shot from the Alaska Volcano Observatory and photographer Dave Ward. Great Sitkin has been at Level Orange and the lava dome has been growing since mid-July. According to AVO, the dome is now 100 meters across. What are the odds of having such a clear day out on Great Sitkin Island? Wonderful shot by Mr Ward.

Great Sitkin has been active most of the summer, although that lava dome build up has occurred in the last couple of weeks.

The glow of Great Sitkin at night. Photo credit: AVO/Peggy Kruse

Both Pavlof and Semisopochnoi Volcanos are also at Level Orange. Pavlof is known to erupt with little to no warning, and it is showing elevated seismic activity, and at least one ash eruption. Explosions and elevated seismic activity on Semisopochnoi Island also continues. At least one ash eruption dissipated quickly, and sulfur dioxide emissions have been detected by satellite.

Cleveland Volcano rounds things out at a Level Yellow. Some seismic activity, but no reported ash eruptions.


Timing is everything

An eruption plume from the Great Sitkin volcano on the Aleutian Chain

Volcanos world-wide seem to be getting a bit anxious of late, and Alaska has three rumbling right now. The Great Sitkin volcano, which dominates the skyline of Great Sitkin Island, erupted on May 25. Lauren Flynn of the U.S. Fish & Wildlife Service captured this image as Great Sitkin erupted. Flynn was aboard the Research Vessel Tiglax at the time.

Great Sitkin Island was a fuel depot during WWII. The island lies between Adak and Atka, and is roughly 11 miles long by 10-1/2 miles wide. The Great Sitkin volcano rises to a height of 5710 feet above sea level.

Photo credit: Lauren Flynn/USF&WS/AVO


Wrangell-St Elias National Park and Preserve

National Park Week Day II; Today’s Park Theme: Volunteer Sunday

The Chitina River en route to McCarthy

Wrangell-St Elias may very well be my favorite road accessible park in Alaska. Denali is closer, and I visit it the most, but Wrangell-St Elias is a trip of its own. First off, it is the largest National Park at 13.2 million acres. It starts at sea level and rises all the way up to 18,008 feet with the summit of Mount St Elias, which is the second highest peak in the United States.

Mount Blackburn

Within Wrangell-St Elias is four mountain ranges: The Chugach, Wrangell, St Elias, and the eastern part of the Alaska Range. Mount Wrangell is one of the largest active volcanoes in North America, and nine of the sixteen tallest peaks in the U.S. are within the boundaries of Wrangell-St Elias.

If you prefer glaciers, Wrangell-St Elias has you covered with 60% of Alaska’s glacier ice within this park. It has the state’s longest tidewater glacier, North America’s largest piedmont glacier, and the world’s longest valley glacier.

The park offers an endless list of things to do. The hiking here is phenomenal, although established trails are few. The beating heart of this park is wilderness. I have seen the gamut of Alaska wildlife with Wrangell-St Elias.

The Kennecott Mine

The Edgerton Highway runs along the Copper River Valley to Chitina, where the McCarthy Road follows the old CR&NW Railway grade to the Kennicott River. For years, you had to stop there to take a tram across the river to the town of McCarthy and the mines of Kennecott. Today, the tram sits unused, and a walking bridge spans the river.

The Kennecott Mine and company town were named after the Kennicott Glacier, but they missed the spelling by a letter. It gets confusing trying to keep it straight. Copper ore was discovered here in 1900, and a rush soon started. Eventually, Kennecott would have five mines operating, but by 1938 operations had shut down. During that time span, the mines produced over 4.6 million tons of copper ore, and gross revenues of $200 million. I’m not sure what that dollar amount would add up to today. The Kennecott Mines are now a National Historic Landmark District.

McCarthy, Alaska in 1915
McCarthy Hardware in 2011

The population of McCarthy in 1920 was 127. By 2010 it had dropped to 28.

Some of the mines like Jumbo can be hiked to, and the green of copper ore can still be seen in the rocks around the area.

Fishing the Copper and Chitina Rivers is an Alaskan tradition, going back millenniums. Dipnetting for salmon is restricted to Alaska residents, but I can tell you that it is an adventure like no other.

If you want a park that you can disappear into, Wrangell-St Elias may just be the place for you. 2018 saw only 79,450 to the nation’s largest park. Like Alaska in general, that’s a lot of elbow room.

Find your Park!

Veniaminof goes Orange

Mount Veniaminof; Photo credit: AVO/Allan Lerner

Mount Veniaminof, which is located on the Alaska Peninsula, erupted last Thursday. The ash plume that exploded from the volcano did not reach 10,000 feet. Veniaminof last erupted in the fall of 2018.

Mount Veniaminof is a rather active stratovolcano, having erupted at least 14 times in the past 200 years. It is surrounded by a 25 square mile ice field. According to the National Park Service, the glacier is the only one known in North America with an active volcano at its center.

Image credit: AVO/Hannah Dietterich

As of 7 March, Veniaminof continued to show an ash plume via satellite imagery. Mount Veniaminof rarely shows itself for the camera. The volcano is visible only one or two days a year, the rest of the time, Veniaminof is shrouded in clouds and fog.


Mount Shishaldin

Shishaldin8.20.2008--Cyrus_Read.jpg

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-volcano-january-2-2019-bg.jpg

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.

276919041_a120a37203_b.jpg

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


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.


Brewing on 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.


Kodiak after Novarupta

Kodiak, Alaska in 1912


Photo courtesy of Katmai National Park & Preserve

The Alaskan community of Kodiak one day after the eruption of Novarupta in 1912. Over a foot of ash fell on the town, collapsing roofs and engulfing the area in near total darkness.


Novarupta: Revisited


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
*

* geology.com