Experts of the Red Sismológica Nacional (RSN) – National Seismological Network – say the phreatic eruption in the Poás Volcano, (Spanish: Volcán Poás) this week is keeping them active as explosions release acid gas.

On Wednesday May 1 A phreatic explosion occurred from the crater lake. On Wednesday a small earthquake swarm occurred probably caused by fluid movements bringing heat into the crater lake.

Although the phenomenon occurs frequently, volcanologists highlight the fact that this time it activity is not in the lagoon, as usual, but rather on a rock structure.

The explosion has caused large rocks to come loose and the gassy smoke reaching 700 degrees Celsius.

The experts are keeping the volcanic activity very closely, especially the decreasing level of lagoon that has dropped almost a metre (three feet) in the week.

For now the Parque Nacional Volcán Poás is open to the public. Experts urge caution when visiting the volcano.

The Poás has erupted 39 times since 1828.

Poás was near the epicentre of a 6.1-magnitude earthquake in January 2009 that killed at least forty people and affected Fraijanes, Vara Blanca, Cinchona (the most affected area), the capital San José, and the Central Valley.

There was also eruptive activity in 2009 involving minor phreatic eruptions and landslides within the northern active crater. Poás eruptions often include geyser-like ejections of crater-lake water.

Poas volcano eruptions: 1828, 1834, 1838(?), 1860, 1879(?), 1880, 1888-91, 1895, 1898-1907, 1910, 1910, 1914, 1914-15, 1925, 1929, 1941-46, 1948-51, 1952-57, 1958-61, 1963, 1964-65, 1967, 1969, 1970, 1972-73, 1974-75, 1976, 1977, 1977-78, 1978, 1979-80, 1980, 1981, 1987-90, 1991, 1992, 1992-93, 1994, 1996, 2010, 2011, 2012

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