The area affected by a December 8, 1994 phreatic explosion is visible from the NW rim of Irazú's summit crater. The explosion originated from a fumarolic area (lower right) on the upper NW flank and produced ashfall to about 30 km from the vent, destroying forests down to 2500 m elevation. The explosion, which produced no juvenile material, created an irregular crater 60-80 m in diameter. Landslides and lahars traveled down the Río Sucio drainage (right center).

Photo by Lee Siebert, 1998 (Smithsonian Institution).

Irazú