This area was impacted by an 8 December 1994 phreatic explosion is visible from the NW rim of Irazú's summit crater, seen here in 1998. The explosion originated from a geothermal area (lower right) on the upper NW flank and destroyed vegetation down to 2,500 m elevation. The explosion, which produced no juvenile material, created an irregular crater 60-80 m in diameter and sent ashfall to about 30 km distance. Landslides and lahars traveled down the Río Sucio drainage (right center).

Photo by Lee Siebert, 1998 (Smithsonian Institution).

Keywords: environmental impact | vegetation

Irazú