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TITLE: 5,700 B.C.—Mount Mazama Erupts

About 7,700 years ago, a group of overlapping volcanoes called Mount Mazama was the site of a colossal eruption that produced a caldera 8-9 km (5-6 mi) wide and 589 m (1,932 ft) deep. It later filled with water, creating the deepest lake in the United States: Oregon’s Crater Lake.


Far-flung Ash

The eruption of Mount Mazama was one of the largest on Earth in the last 10,000 years. It ejected 100 cu km (24 cu mi) of pumice and ash enough to bury Washington, D.C., under a layer 568 m (1,860 ft) deep! More than 1 cm (0.4 in) of ash fell in Canada’s province of Saskatchewan, 1,200 km (750 mi) away.


Pyroclastic Falls, Pyroclastic Flows

Like many explosive eruptions, the Mount Mazama event blasted some particles into the air (producing pyroclastic falls) and sent others flowing along the ground (creating pyroclastic flows).


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Smithsonian National Museum of Natural History Department of Mineral Sciences website Credits