Chaiten Volcanic Eruption Flashcards
What caused the Chaiten eruption?
- oceanic-continental convergence between Nazca & S. American plates
- melting of Nazca plate in asthenosphere
Why is the Southern part of Chile extremely volcanically active compared to the Northern part?
- oceanic plate dips at steep angle at the southern part of the subduction zone
- whilst northern end may be experiencing flat-slab subduction.
What fold mountain chain is Chaiten apart of?
-the Andes (longest fold mountain chain)
What hazards did the eruption cause at Chaiten?
-numerous plums, pyroclastic flows, minor earthquakes and lahars
What impact did the lahars cause?
- it inundated the nearby town of Chaiten (10km Southwest)
- cut communications in areas
- and made access difficult
What impact did the ash cloud have?
- caused 4,000 to evacuate by boat from the town of Chaiten and 1,000 from town of Futaleufu as they were blanketed with ash
- effected smaller communities with heavy ash falls
Which airports were forced to close or cancel flights due to the ash cloud and why?
- airports in Argentina and Uruguay closed
- due to significant engine damage of airplanes that encountered the eruption ash-cloud
What were the impacts of the ash falls?
- blocked rivers
- contaminated water supplies
- suffocated farm animals.
How much of the town of Chaiten was reported damaged and what was the main cause of the destruction?
- 80-90% Chaiten was destroyed
- due to flooding of the river Blanco.
What type of country is Chile in terms of development and how well is it at prediction, preparation and prevention?
- EDC
- has got some armed services
- stable democratic government
- should be relatively good at prediction, preparation and prevention.
What was Chile’s vulnerability like to the Chaiten eruption?
- low population density (impacts localized), only town of Chaiten & Futaleufu in vicinity
- vulnerable to earthquake and volcanic events due to tectonic setting at a subduction zone
What was monitoring like of the volcano Chaiten? Why was it like this?
- not high as volcano was considered dormant (last erupted 9,400 years ago) = low risk
- single volcano observatory
- many other active volcanoes in the area
What was the VEI of Chaiten classified as and what type of eruption did this go on to produce?
-VEI (Volcanic explosive index) of 4 = explosive eruption
What type of lava did the old lava dome consist mainly of and where was the new lava dome created?
- rhyolitic lava dome
- new dome built north side of old one
Who helped with the evacuation of 3,900 people?
-the Chilean Navy
