Chaiten, Chile Case Study

Case study: Chaiten, Chile

Background information:

· Took place on Friday 2^nd May 2008

· This was its first eruption in 9,400 years

· The initial eruption let off a plume of ash and steam which rose up to 17km high. Winds spread this plume over to Argentina, then over the Atlantic

· The town of Chaiten, which is 10km from the volcano was blanketed with ash

· 4000/4200 people were evacuated by boat along with 1000 people from a nearby town

· The ash was so thick in Argentina that planes were stopped, schools were shut and highways closed

Timeline:

· First earthquake was on 30/04/08

· Eruption began on 01/05/08

· Initial eruption led to an ash column 18km, 6 hours duration

· Continuous ash emission as high as 30km with large explosions continuing from 2-8^th May

· Lava dome extrusion with sustained vapour and ash column

· Situated above a subduction zone where the Pacific Ocean Plate is consumed beneath the South American continental crust

· Was a caldera 2.5km wide and 4km long, composed of viscous rhyolitic lavas and pyroclastics

The nature of the volcanic hazard

· By late May the lava eruptions had generated a new dome of around 540,000m in area, containing 55million m of new material

· The ash column was at its peak between 20-30km high

· The fall…