Surprise Eruption in Chile Sparks Interest in Volcano Early Warning

Typical eruption column of Chaitén Volcano, Chile, on May 26, 2008, between stronger explosive activity. The circular caldera rim is 3 km (1.9 miles) in diameter, which was formed about 9,400 years ago. A lava dome that erupted sometime later is the knobby feature between the billowing ash and rim on the left. A new lava dome is growing in the caldera but it is out of view behind eruption column. U.S. Geological Survey photograph by J.N. Marso.