GlacierDogMapMe: Where Was the Largest Volcanic Eruption of the 20th Century?
* 100 years ago in June 1912, the 20th century experienced its largest, most voluminous, explosive volcanic eruption. It occured in Alaska and formed the huge lava dome, Novarupta. In what is now Katmai National Park and Preserve, over 3 cubic miles (about 13.5 cubic kilometers) of magma blasted through the floor of a broad glacial valley for 60 hours. Clouds of ash rose high into the atmosphere and drifted downwind, dropping more than a foot of ash on Kodiak, dusting Puget Sound, and eventually circling the globe. The ash and gas cloud colored the Mediterranean sky and measurably depressed global temperatures. The eruption was also correlated with some 50 earthquakes recorded at distant seismic stations (including 14 shocks of magnitude 6.0 to 7.0) and produced a series of ash flows that filled what became the Valley of Ten Thousand Smokes.
* 6 miles from erupting Novarupta, Mount Katmai collapsed into a deep, steep-walled, steaming crater. For many years Katmai was believed to be the volcano creating the massive eruption. But in the 1950s geologist Garniss Curtis carefully mapped ash thicknesses that identified Novarupta as the culprit.
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