Check it out and give us feedback.
View Site
USGS - science for a changing world

The USGS Visitors Center at the National Center in Reston, Virginia

Maps, Imagery, and Publications Hazards Newsroom Education Jobs Partnerships Library About USGS Social Media

Earth Science Quiz Answer to largest active volcano in US


a geyser
The youngest caldera is an elliptical depression, nearly 80 kilometers long and 50 kilometers wide. Most of Yellowstone National Park lies inside the caldera. The caldera is buried by several extensive rhyolite lava flows erupted between 75,000 and 150,000 years ago.
Yellowstone Caldera is one of the largest and most active volcanoes in the world. Cataclysmic eruptions 2.0, 1.3, and 0.6 million years ago ejected huge volumes of rhyolite magma. Each eruption formed a caldera and extensive layers of thick pyroclastic-flow deposits.
map of Yellowstone Caldera

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Ask USGS
Page Last Modified: Friday, October 02, 2009