Lava dome at Katmai National Preserve, AK.

Katmai National Park and Preserve, Alaska. 80-meter (260-foot)high Novarupta, a blocky rhyolite lava dome that marks the vent for the June 1912 eruption that created the Valley of Ten Thousand Smokes. 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. Falling Mountain, a lava dome truncated by the 1912 eruption, is visible behind the Novarupta dome. Snow-capped Mount Mageik volcano can be seen at the top.