A Katmai National Park's eruption happened a century ago Wednesday -- but it is still the largest volcanic blast in nearly 200 years, easily loud enough to have been audible 290 miles away where Anchorage now stands.
On June 6, 1912, the Novarupta stratovolcano produced the biggest volcanic eruption of the 20th century: bigger than the 1883 eruption of Krakatoa (more properly called Krakatau) in Indonesia, as well as Mount Pinatubo's 1991 blast in the Phillipines. It was 30 times larger than the spring 1980 eruption of Mount St. Helens, which killed more than 50 people in Washington State in the spring of 1980.
Because Alaska was so sparsely populated in 1912 (U.S. Census figures show only about 50,000 people lived in the territory at the time), only one person died in the eruption of Novarupta. She was an elderly woman suffered respiratory arrest on Kodiak Island, 160 miles away. That's where an ash cloud averaging a foot thick settled down.
Novarupta sits in what geologists call a subduction zone -- basically a seam in the Earth's crust where two tectonic plates collide, triggering earthquakes and violent volcanoes.
When Novarupta exploded in 1912, the sound was heard nearly 800 miles away in Juneau. By 6 p.m. on the day of the eruption, Kodiak Island was in complete darkness.
The biggest blast from the volcano was on June 6, but eruptions continued for another three days. Novarupta's total output from the duration of the eruption was greater than that of all other Alaska volcanoes in recorded history combined.
What's worse, it could happen again. In fact, it will happen again. The U.S. Geological Survey says another eruption in the Valley of 10,000 Smokes is inevitable, but nobody knows when -- it could be next year, or centuries in the future.
The USGS says a new eruption would force airports across Alaska to close due to the resulting ash cloud. The effects could ground planes as far away as Canada, the Lower 48 and Europe as well.
Kodiak Island would once again be covered in a foot of ash, but it's not clear whether the island would have to be evacuated. Depending on the amount of notice, advising residents to take shelter in their homes might be the best course of action, but life on the island would be hard for a long time afterward.
Until then, Novarupta remains on the books as the world's largest eruption since Indonesia saw the eruption of the Tambora volcano in 1815.
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