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Wednesday 18 March 2015

Villarrica eruption

Villarrica, a stratovolcano located in southern Chile erupted spectacularly on 3rd March causing authorities to evacuate over 3600 people from the vicinity of the volcano.


The volcano, measuring 2847 metres  is one the country’s  most active volcano with numerous documented eruptions of which the majority have been a VEI 1 or VEI 2. Villarrica’s most violent eruptions according to radicarbon dating took place  in 1810 (+/- 200) measuring a VEI 5 and in 0670 BCE measuring a VEI 4.


According to the Global Volcanism Program, Villarrica showed signs of activity in early December last year; however the activity was minimal and only began to intensify in February 2015. In early February the volcano experienced an increase in seismicity, sulphur dioxide emissions, crater incandescence and lava lake temperature. Strombolian eruptions took place during early to mid February emitting ash plumes and ejecting tephra (including lava bombs measuring 5 metres in diameter) several metres high.


From 28th February to 2nd March the volcano showed signs of greater increase in activity including significant seismic activity, further strombolian activity, ejection of tephra and an increase in the level of the lava lake.  On 3rd March at approximately 03:00 am after an increase in seismic levels the most significant eruption took place. A lava fountain was produced reaching heights of 1.5 km, tephra was ejected several metres around the volcano and lava flows travelled down the volcano. An ash plume was also produced, reaching a height of up to 8 km and travelled 400 km towards the east.


The Alert Level was raised to Red from Orange and a 10 km exclusion was placed as a result of the increased intensity of the eruption. Residents within this zone including those from the towns of Pucon and Conaripe were evacuated as a precautionary measure but returned when the intensity of the eruption decreased later that evening. 


Due to a decline in activity on 5th March, the exclusion zone was reduced to 5 km and the Alert Level was lowered to Orange. A further decline in activity continued at the volcano, including decrease in seismicity and the absence of an active lava lake on 6th March and subsidence of material in the crater and decrease in gas levels on 9th March. The Alert Level was lowered to Yellow on 10th March as a result; however a 3 km exclusion zone remains due to fear of avalanches on the volcano.

Source: Reuters

Source: EPA (Francisco Negroni)

Source: Rocuant/AFP/Getty Images

Source: AP, Aton













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