Irazu Volcano National Park

  The name comes from the indigenous word istaruqeu which means hill of tremor. Through the years it has been changed to Irazú.  Its activity has been documented from the beginning of the Spanish colony (1563). The first known eruption dates from 1723 and the last strong period of activity was between 1963-65. On a clear day, the Pacific Ocean can be seen along with Atlantic. With a telescope, the Nicaraguan lake can also be seen.  In 1955, it was created as park through article No. 4 by the Costa Rican Tourism Insitute. The  National Parks Services started park adminstration from 1970. The park measures 2000 hectares. It is an active volcano with a long history of eruptions and eruptives cycles and is a zone of great hydrological importance. Several rivers are born here that feeds the river basins on the Chirripó River, Reventazón River, River Sarapiquí and Ri'o Grande de Tárcoles.

  Irazú is a strato volcano (layers differentiated by volcanic material) located in an altitude of 3432 ms, with violent eruptions and five differentiated craters. The most important are: the main crater, where the bottom has a permanent pond with yellowish and  green color, the Diego crater, Playa Hermosa, lagoon and the pyroclastic apt. The outer slope of the main crater  can be seen emitting water steam and gases.