Irazú Volcano

Lore & Background

The name Irazú may come from the combination of 'ara' (point) and 'tzu' (thunder) or a corruption of Iztarú, an indigenous village on its flanks. In Costa Rica it is known as 'El Coloso' (the Colossus) due to past catastrophes. The volcano's summit has several craters, including the Main Crater, which is 1,050 meters in diameter and 300 meters deep, and the Diego de la Haya crater, which is 600 meters in diameter and 100 meters deep and contains a green crater lake of variable depth.

Reader's Guide

Irazú Volcano has erupted at least 23 times since its first historically recorded eruption in 1723. Its most famous eruption began in mid-March 1963, just before US President John F. Kennedy's state visit to Costa Rica, showering San José and the central highlands with volcanic ash for two years. Historical eruptions generally have VEIs of 1 to 3, are explosive, and include phreatic eruptions and pyroclastic flows. The latest eruption, on December 8, 1994, was a one-day phreatic event at a flank vent that produced lahars. The volcano is a popular tourist spot, easily visited from San José via a road to the summit, and on clear days both the Atlantic and Pacific oceans are visible, though such days are rare. The summit also houses television transmitters for San José stations.

Did You Know?

• The volcano's summit has four main craters, including the green crater lake Diego de la Haya.