Alaska Volcano Observatory

Aerial view of 80-m (260 ft)-high Novarupta, a blocky rhyolite lava dome that marks the vent for the 1912 eruption that created the Valley of Ten Thousand Smokes in Katmai National Park and Preserve, Alaska. This eruption was the most voluminous on Earth in the 20th century, ejecting nearly 30 cubic kilometers (7 cubic miles) of material in 60 hours. Surrounding the dome is an oval-shaped ring of coarse tephra that accumulated during the waning explosive phases of the 1912 eruption. Photograph by C. Nye, Alaska Division of Geological and Geophysical Surveys, August, 1991.