Chaiten | Universe Today

Written by Jerry Coffey

Chaiten is a volcanic caldera in Chile that is about 3 km in diameter. The caldera rim reaches 1,122 m above sea level. The volcano has erupted many times with the most recent eruption being on May 2, 2008. The volcano's last eruption had followed a very long period of quiet. According to carbon dating of the previous lava flows, the volcano had not erupted since 7420 B.C. The volcano is 17 km west of the elongated, ice-capped Michinmahuida volcano, and 10 km northeast of the town of Chaiten in the Gulf of Corcovado.

Prior to the current eruption, Chaiten was mostly filled by a rhyolite obsidian lava dome that reached a height of 962 m, partly devoid of vegetation. Two small lakes occupied the caldera floor on the west and north sides of the lava dome. The translucent gray obsidian which had erupted from the volcano was used by pre-Columbian cultures as a raw material for artifacts and have been found as far away as 400 km to the north and south. Rhyolite volcanoes do not erupt very often. This eruption is known as the first major explosive eruption of rhyolite magma volcano in nearly a century. The last was the 1912 eruption of Novarupta. Although there have been rhyolitic eruptions in the southern section of the Southern Volcanic Zone in the past, these are relatively scarce and there is no historic rhyolitic eruption of the magnitude of Chaitén.
The Chilean government began an evacuation of the nearby town of Chaiten and the surrounding area the same day as the eruption began and was completed by May 3, 2008. One elderly person died. 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 towns. Ash thickness estimates are often exaggerated during volcanic crises; later field investigations suggest that the average ash thickness deposited was less than 5-10 cm.

Chaitan was still active on February 19 2009 when a partial dome collapse caused pyroclastic flows to descend through the Chaitén river valley reaching approximately 5 km from the town of Chaitén. The ash once again reached the town of Futaleufu and parts of Chubut province in neighboring Argentina. The volcano remains listed as active and few people have returned to the neighboring town of Chaiten.

There is a good article about Chaiten here. We have a great article about the Chaiten volcano causing lighting storms here on Universe Today. Astronomy Cast offers a good episode about how volcanoes have shaped the Earth and other planets.

Filed under: Astronomy

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