Everything you need to know about Chile's volcano eruption

For the first time in 42 years, the Chilean volcano, Calbuco has erupted, spewing vast clouds of ash into the skies of southern Chile.

Here are the basic facts on the eruption and what it means for the local population...

Where is it?

Roughly 1,000km south of Chile's capital Santiago, Calbuco is situated in a (relatively sparsely populated) national reserve. Residents from the nearby towns of Ensenada, Puerto Varas and Puerto Montt have all been evacuated from a 20km radius around the erupting volcano. Such is the potential scale of the eruption that the Argentinian city of Bariloche - some 100km away - is also bracing itself with emergency measures in case the ash cloud rolls in.

What threat does it pose?

With some 500 potentially active volcanoes, Chile is no stranger to eruptions - but the Calbuco eruption has taken local authorities by surprise. An emergency director for the region, Alejandro Verges, told international media that Calbuco had not been under any "special form" of observation before the eruption on 22 April. Some 4,000 people have been evacuated from the 20km radius as a precaution, with local schools closed, planes grounded and residents advised to stay indoors - avoiding potential 'lahars', a nasty blend of water and rock fragments that can cascade down a volcano's slopes.

What happened last time it erupted?

The eruption in 1972 only lasted for four hours, spewing ash into the air after a "relatively weak" explosion. A more potent eruption occurred in 1961: lasting for the better part of a month between February and March, Calbuco produced an ash cloud that extended some 15km into the air as it formed a new lava dome that broke through the glacier filling its summit crater. Rivers of lahar reached as far as the shore of Lake Llanquihue, about 10 km north of the summit, while lava flowed from its crater.

What does it look like?

Frankly, beautiful - in a terrifying sort of way. Initial eruptions at 18:00 local time caused vast amounts of ash to fill the sky, before "dirty thunderstorms" set in. You can watch footage of the fireworks below.

[Via: The Guardian, AFP]

(Images: Rex)