Poas Volcano

Poas Volcano stands in Alajuela Province, Costa Rica, part of the Cordillera Central within the Central America Volcanic Arc, reaching about 2,708 meters. It is an active stratovolcano with a large active crater, roughly 1.3 kilometers across, holding one of the most acidic crater lakes in the world, Laguna Caliente, whose water can approach a pH close to zero because of dissolved sulfuric and hydrochloric gases venting from below. The volcano has a long history of phreatic and phreatomagmatic eruptions, explosive events driven by the interaction of magma-heated water and steam with the crater lake and groundwater, punctuated by longer quiet periods during which the lake refills. A significant eruptive episode from 2017 into subsequent years produced ash plumes and forced repeated closures of the surrounding Poas Volcano National Park, one of Costa Rica's most visited protected areas. This entity documents Poas Volcano specifically as a geological formation, an active stratovolcano holding one of the world's most acidic crater lakes.