Editor's Summary

2 March 2006

Echo from a supervolcano

Yellowstone National Park is on the site of one of the largest volcanoes on Earth, a super-explosive volcano that last erupted about 640,000 years ago, ejecting 1,000 cubic kilometres of material in the process. Supervolcanoes have had far-reaching effects on topography, climate and biosphere, so researchers have followed many different avenues in the attempt to understand them. Now using radar interferometry data from the European Space Agency's ERS-2 satellite, a group from the US Geological Survey has identified an unusual feature at Yellowstone, the uplift of a large area about 30 by 40 km centred under the north rim of the caldera. Even more unusually, during the uplift episode the caldera floor has subsided. This type of deformation has not been seen before and has profound implications for the workings of large active calderas. The cover shows Steamboat Geyser, the world's tallest active geyser, taken on 23 October 2003 by park geologist Henry Heasler.

LetterUplift, thermal unrest and magma intrusion at Yellowstone caldera

Charles W. Wicks, Wayne Thatcher, Daniel Dzurisin and Jerry Svarc