Irazu volcanIrazú (3432 m) immediately east of the capital San José is Costa Rica's highest and one of its most active volcanoes. Tephra fall (ash) during the last major eruption of Irazú in 1963-65 caused heavy damage to infrastructure and life in San José and its surroundings.
Introduction:Irazú is a massive stratovolcano covering more than 500 sq km with at least 10 flank cones on the southern flank, all being older than at least 14,000 years when a massive lava flow (the "Ceravantes" flow) was erupted.
All known eruptions from Irazú during the past 10,000 years have been explosive and originated from the summit craters that show a migration to the W over time. The historically active crater contains a small acid lake of changing size and color.
Source: GVP, Smithsonian Institution