Chaitén (volcano)

Chaitén is a volcanic caldera in diameter, west of the elongated ice-capped Michinmahuida volcano and northeast of the town of Chaitén, near the Gulf of Corcovado in southern Chile. The most recent eruptive phase of the volcano erupted on 2008. Originally, radiocarbon dating of older tephra from the volcano suggested that its last previous eruption was in 7420 BC ± 75 years. However, recent studies have found that the volcano is more active than thought. According to the Global Volcanism Program, its last eruption was in 2011. The caldera rim reaches above sea level. Before the current eruption, it was mostly filled by a rhyolite obsidian lava dome that reached a height of , partly devoid of vegetation. Two small lakes occupied the caldera floor on the west and north sides of the lava dome. The translucent grey obsidian which had erupted from the volcano was used by pre-Columbian cultures as a raw material for artifacts and has been found as far away as to the south and north, for example in Chan-Chan. The Chaitén volcano entered a new eruptive phase for the first time since around 1640 on the morning of May 3, 2008. The Chilean government began an evacuation of the nearby town of Chaitén (population 4,200) and the surrounding area the same day, the main phase of which was completed by May 3, 2008. One elderly person died while at sea en route to Puerto Montt. By the afternoon of May 3, the plume of ash from the eruption had spread across Chile and Argentina to the Atlantic Ocean, contaminating water supplies, and reportedly coating the town of Futaleufú located southeast to a depth of . Ash thickness estimates are often exaggerated during volcanic crises; later field investigations suggest that the average ash thickness deposited across Futaleufú was less than . A team of scientists from the US was dispatched to the area to assess the air quality and the risks from chemicals in the falling ash. The initial phase of the actual eruption in 2008 was characterised by ash emissions and seismic activity; local seismic measurements in 2005 registered earthquakes up to magnitude 3.