This is a destructive margin, where the denser Nazca plate is subducted beneath the less dense continental lithosphere of the South American plate.
Chaitén explosive because the lava is Rhyolitic has high gas pressure and high Silica content.
Chaitén is also part of the world’s longest fold mountain chain, the Andes Mountains.
USGS conducting Real-time seismic monitoring.
Eruption:
In May 2008, Chaitén began erupting violently, producing numerous plumes, pyroclastic flows, minor earthquakes and lahars, and building a new lava dome on the north side of the old one. The ash cloud was up to 17 kilometers high and was visible on satellite images for hundreds of kilometers over the Atlantic.
This area of Chile has reasonably low population density. Only the towns of Chaitén and Futaleufu are in the vicinity.
Impacts:
Eruption has had serious consequences for the nearby town of Chaitén, inundating it with lahars and ash, and ash from the eruption has even disrupted travel and agriculture in surrounding countries.
Chaitén blanketed with ash. 4,000 people who lived there were evacuated by boat. The town of Futaleufu, with about 1,000 residents, was also evacuated.
Lahars had cut communications in areas and made access difficult whilst ash falls up to 15cm deep had blocked rivers and contaminated water supplies.
Just one death caused by stress.
Responses
Chilean government ordered the complete evacuation of the town.
Residents were told not to drink the water.
Chilean officials distributed facemasks and fresh water.
The Chilean government ordered a50km exclusion around the town.
Financial aid to small businesses was granted and 90 day freeze on payment of existing loans.