Chaiten, Chile volcanic eruption

Question 1

Location

Answer 1

• West coast of South America
• Convergent boundary
• Nazca plate sub ducting under the S.A plate
• Sits above the Peru-Chile subduction zone

Question 2

Vulnerability

Answer 2

• Low population density
• Small impact on local scale
• Vulnerable to earthquake and volcanic events (Chaiten and Futaleufu)
• Polar storms mixed with ash making the hazard worse
• This created lahars and river flooding

Question 3

Nature of hazard

Answer 3

• VEI of 4
• infrequenct
• Rhyolitic lava dome, last active 9400 years ago

Question 4

Eruption details

Answer 4

• 2008 violent eruption
• Pyroclastic flow, minor earthquakes and lahars.
• Lava dome built on North side
• 17km high ash cloud
• High Plinian eruption of ash gas and rock
• Dome was 540,000m^2 containing 55m^3 of material

Question 5

Capacity to cope

Answer 5

• Prediction, preparation and prevention were poor
• only 7/20 volcanoes on island measured
• Chaiten was a low threat volcano so no monitoring
• Low population =little managaement.
• No real time monitoring until 15 days after 1st eruption by the USGS
• Chile has a stable armed government so the armed services =aid.

Question 6

Social impacts

Answer 6

• Chaiten (10km away) blanketed with ash
• 4000 evacuated by boat
• 1000 evacuated from Futaleufu
• Nationally, plume was so thick, schools, highways and airports forced to close in Argentina
• Communication cut due to lahars
• Respiratory problems for residents
• Unclean water= disease
• Loss of jobs in agriculture
• 1 death

Question 7

Environmental impacts

Answer 7

• 15m of ash fall= blocked rivers= contaminated water supplies
• 90% of chaiten was flooded
• Farm animals killed due to suffocation from ash
• 80-90% of Chaiten was damaged
• Marine life affected
• 20-30% of town completely destroyed
• LAND NOW HIGHLY FERTILE

Question 8

Economic impacts

Answer 8

• High evacuation/ relocation cost
• Airline industry suffered in Chile and Argentina (5 planes encountered ash, several got engine damage,
• Airports upto 2,300 km away had to cancel flights
• GDP locally dropped as agricultural FACILITIES ARE DESTROYED

Question 9

Immediate responses

Answer 9

• 5000 evacuated by Chilian Navy on, 3,900 by the 3rd May
• 90 day freeze of payment on loans
• Financial aid to small businesses
• Residents told not to drink water
• 50km exclusion zone
• Face masks and fresh water distributed
• 2 year after rebuilding began new site location made.

Question 10

Long term response

Answer 10

• Volcano began to be seismically monitored
• Assessments made of volcanic hazards
• Creation of real time monitoring network
• Volcano disaster assistance program set up
• Chaiten town relocated completely, 10km away from previous site
• early warning systems put in.