Yellowstone's Echinus Geyser erupted for the first time in six years, with multiple bursts reported in February.

When geologists study volcanic hazards or try to anticipate what a volcano may do in the future, one of their primary tools is to examine the volcano’s past behavior.

Yellowstone National Park sits atop one of the most studied volcanic systems on Earth, and the question of what a full-scale caldera-forming eruption would do to the United States draws enormous ...