Costa Rica Volcanoes
Costa Rica`s three separate volcanic mountain ranges, Guanacaste, Tilaran and Central comprise some of the most amazing volcanoes in the world, from active ones like Poas, Turrialba and Arenal to majestic dormant ones like Tenorio and Barba.
Turrialba, (3,340 meters) the southeast-most of Costa Rica's Holocene volcanoes, is a large vegetation-covered stratovolcano located to the northeast of Irazu volcano. Three well-defined craters occur at the upper end of a broad summit depression that is breached to the northeast. Turrialba has been quiescent since a series of explosive eruptions in the 19th century that were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the summit craters.
Rincon de la Vieja
Rincon de la Vieja, the largest volcano in northwest Costa Rica, is a remote volcanic complex in the Guanacaste Range consisting of an elongated, arcuate NNW-SSE-trending ridge. At least nine eruptive vents are located within an older 15-kilometer-wide caldera remnant, with activity migrating to the southeast, where the youngest-looking craters are located. The twin cone of 1,916-meter-high Santa Maria volcano, the highest peak of the Rincon complex, is located at the eastern end of a smaller, 5-kiloeter-wide caldera and has a 500-meter-wide crater. A Plinian eruption producing the 0.25 cubic kilometers Rio Blanca tephra about 3,500 years ago was the last major magmatic eruption from the volcano. All subsequent eruptions, including numerous historical eruptions possibly dating back to the 16th century, have been from the Active Crater, which contains a 500-meter-wide crater lake.
Poás, one of the most active volcanoes of Costa Rica, is a broad, well-vegetated volcano with a summit area containing three craters along a north-south line. The frequently visited multi-hued summit craters of one of Costa Rica's most prominent natural landmarks are accessible by vehicle. The 2,708-meter-high complex stratovolcano is constructed within eroded remnants of nested 7- and 3-kilometer-wide calderas. A north-south-trending fissure extending to the lower north flank has produced the Congo stratovolcano and several maars. The southernmost of two summit crater lakes, Botos, is cold and clear, and last erupted about 7,500 years ago. The other is warm and acid and has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Poás eruptions often include geyser-like ejection of crater lake water.
Miravalles (2,208 meters) is an andesitic stratovolcano that is one of five post-caldera cones along a northeast-trending line within the Pleistocene, 15 x 20 kilometer Miravalles caldera. Morphologically youthful lava flows cover the western and SW flanks of the volcano. The only reported historical eruptive activity was a small steam explosion in 1946, although high heat flow remains and a geothermal field is located within the caldera.
Costa Rica's highest volcano, Irazú has a broad summit, vegetated flanks, and a history of frequent eruptions going back to 1723. Its last eruption, 1963-65, sent tephra and secondary mudflows into cultivated areas, caused at least 20 deaths, and destroyed 400 houses and some factories. ...
The Arenal Volcano lies directly adjacent to Lake Arenal, a dammed reservoir for generating hydroelectric power. The volcano has been watched by many tourists from a mountain lodge 2.8 kilometers (1.75 miles) south of the vent that enables visitors to hear, to see, and occasionally to smell its dynamism