Volcanic Gas Precursors to Phreatic Eruptions at Poás Volcano, Costa Rica

Poás volcano (Costa Rica) is one of the most chemically extreme environments on Earth, hosting an ultra-acidic crater lake (pH ~0, T ~50°C) as well as high temperature fumaroles (up to ~800°C in recent years). The lake was the site of intense phreatic eruptive behavior between 2006 and 2014. Volcanic eruptions involving interaction with water are particularly energetic, causing a disproportionate number of human casualties. Phreatic eruptions are also exceedingly difficult to forecast, often occurring with little or no geophysical precursors.

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