Tag Archives: novarupta

Historic Ash

Kodiak Island just Southeast of Katmai

Kodiak Island had a somewhat unique Winter Warning on Thursday. Mixed in the fresh snow was some ancient volcanic ash. Ash from the Novarupta eruption of 1912 was carried across the Shelikof Strait due to some high winds, and the ash came down with the recent snowfall. The ash was not expected to climb above 7000 feet, but airlines were notified, and air quality on the island may have been diminished.

Ashfall, over a foot deep, on Kodiak Island; June 1912

The Novarupta eruption started on 6 June 1912, and lasted three days. The eruption was the most powerful of the 20th Century. The ash cloud is thought to have risen to over 100,000 feet, which is incredibly impressive. An estimated 3.6 cubic miles (15 cubic KMs) of magma erupted. That’s 30 times more than the Mount St Helens eruption. As much as 600 feet of ash was dumped on the region now known as The Valley of 10,000 Smokes.

The ash kick-up does happen from time to time, when winds hit the area just right, and carry loose ash over to Kodiak.

All seven volcanos in the Katmai region, including Novarupta, remain at Level Green.


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
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* geology.com