Introducing Parque Nacional Volcán Irazú
Looming on the horizon 19km northeast of Cartago, Irazú, which derives its name from the indigenous word ara-tzu (thunder-point), is the largest and highest (3432m) active volcano in Costa Rica. In 1723 the Spanish governor of the area, Diego de la Haya Fernández, watched helplessly as the volcano unleashed its destruction on the city of Cartago (one of the craters is named in his honor). Since the 18th century, 15 major eruptions have been recorded.
One of the most memorable occurred in March of 1963, welcoming visiting US President John F Kennedy with a rain of volcanic ash that blanketed most of the Central Valley (it piled up to a depth of more than 0.5m). During two years worth of subsequent activity, agricultural lands northeast of the volcano were devastated, while clogged waterways flooded the region intermittently. In 1994 Irazú unexpectedly belched a cloud of sulfurous gas, though it quickly quietened down. At the time of research, the volcano was slumbering peacefully, aside from a few hissing fumaroles.
The national park was established in 1955 to protect 23 sq km around the base of the volcano. The summit is a bare landscape of volcanic-ash craters. The principal crater is 1050m in diameter and 300m deep; the Diego de la Haya Crater is 1000m in diameter, 80m deep and contains a small lake; and the smallest, Playa Hermosa Crater, is slowly being colonized by sparse vegetation. There is also a pyroclastic cone, which consists of rocks that were fragmented by volcanic activity.