The Poas Volcano experienced a phreatic eruption this afternoon, at 14h27. A column of 200 meters above the level of the acid lake of the active crater has risen. A phreatic eruption is the compound of the emission of steam and rock fragments, without emission of magmatic products, which occurs as a result of heating of groundwater by a magmatic concentration
The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica’s most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2708-m-high complex stratovolcano extends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world’s most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Eruptions often include geyser-like ejections of crater-lake water.
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July 06, 2016.Poas , Costa Rica :
Source : Ovsicori , GVP.