Frequent historical eruptions have kept the summit craters of Irazú volcano devoid of vegetation. The thick layer of dark-gray ash and scoria that caps the rim at the left center in this photo marks ashfall deposits formed during the 1963-65 eruptions of Irazú, which were among the largest from the volcano in historical time.

Photo by Mike Carr, 1982 (Rutgers University).

Irazú