Volcano case studies

Question 1

Eyjafjallajökull, Iceland

Answer 1

• 2010
• VEI 2-4, large ash cloud
• No deaths, no injuries (potential health problems from ash)
• Constructive boundary: European & N.American
• Phreatic (interaction of water & hot magma)
• Est $2.6bn GDP loss (shut airports)
• Extra business for channel tunnel
• 2.8m tn less carbon emitted

Question 2

Mt Pelee, Martinique

Answer 2

• 1902
• VEI 5, pyro flows
• 29,000 dead (3rd deadliest in history)
• Destructive boundary: S.American & Caribbean
• Crude monitoring & no evacuation despite eary signs of eruption (low tech/knowledge)
• US: $200,000 in aid + navy w/ supplies

Question 3

Montserrat, Caribbean

Answer 3

• 1995-1997
• VEI 3, intermittent pyro flows, ash clouds, lahars
• 19 dead
• 2/3 of island became exclusion zone
• Ex-capital Plymouth buried over time by ash & lahars
• People evacuated to North of island, living in poor quality shelters up to 10 years
• Farmers went back to tend to crops & 9 died (due to long dormant periods as well as arguable lack of land given so farmers needed to go back)
• Damaged environment: coral reefs & chicken frog

Question 4

Nevado del Ruiz, Colombia

Answer 4

• 1985
• VEI 3, lahar
• Lahar triggered by phreatic erruption
• 23,000 dead
• Warnings & requests for evacuation given weeks before but ignored by citizens
• Happened at night, people couldn’t see lahar coming
• Erruption detected, but storm had disconnected communication to Armero –> warning not recieved
• Population never fully recovered, now 12,000
• Evacuation plan made by government was confusing (green = bad, red = good)
• Night time delayed aid, high altitude stopped helicopters, mud stopped heavy rescue machinery

Question 5

Tangiwai, New Zealand

Answer 5

• 1953 & 2007
• 153 dead in 1953 after lahar destroyed railway bridge
• Sensors put in place (e.g. vibration & water level sensors)»_space; alert sent to authorities 2 hr before lahar reaches tracks»_space; trains diverted
• 2007: lahar in same place, 0 deaths

Question 6

Sidoarjo, Indonesia

Answer 6

• 2006-present
• Average 100,000 cubic m /day
• Over 60,000 displaced
• 11 dead
• Suspicion that Lapindo(gas drilling company) caused eruption as bore hole connected to flow

Question 7

Nyiragongo, DRC

Answer 7

• Frequently errupting: 2002, 2021
• Both VEI 2
• Highly populated area (Goma) due to fertile soil
• Highly fluid lava travels up to 60mph & hard to predict
• 2002: 100 dead, 20% of Goma destroyed, shambolic evacuation
• Built an observatory, GVO, which predicted 2021
• 2021: 37 dead (mostly in car crash due to panic), shambolic evacuation again
• Political situation means armed guards needed for seismologists, limits access

Question 8

Pinatubo, Phillipines

Answer 8

• 1991
• VEI 6, pyro flows, lava, ash cloud
• 367 dead
• Ash settled & collapsed 200k buildings
• Ash harmed crop growth for 2 years, but minerals boosted yield after
• 0.5 degree global temp cooling due to ash
• Successful evacuation of 200,000 in weeks leading up to erruption
• Post eruption: risk map created & increase in monitoring (cameras around rim)

Question 9

Eldfell, Iceland

Answer 9

• 1973
• VEI 3
• 1 death (died of heart attack while protecting home)
• 1 mile long fissure erruption
• Slow moving, able to evacuate 6,500 people
• Lasted several months
• 350 homes destroyed
• Seawater pumped & sprayed to solidify lava, saved harbour

Question 10

Toba Supervolcano, Indonesia

Answer 10

• 75,000 years ago
• VEI 8 (highest possible)
• Near extinction of human race caused genetic bottlneck, only those in parts of Africa thought to have survived
• Core sample in Lake Malawi shows plants to be same before & after eruption»_space; winter less severe?
• 6-8 year volcanic winter
• Ash up to 100m thick near volcano

Question 11

Mt St Helens, USA

Answer 11

• 1980
• VEI 5
• 57 dead
• Juan de Fuca subsided under N.American
• M5.1 quake triggered landslide which caused lateral erruption
• $1.1bn cost
• 20 mile exclusion zone (loggers died inside zone ans some outside too)
• Evac policy & exclusion zone based on vertical, not lateral eruption
• Sediment retention system + dredging in Spirit Lake to stop lake collapsing & sediment downstream (should also be don in Lake Nyos however can’t afford»_space; 1300 dead due to gasses)
• Bezimyanny, Russia 1956 same erruption type but no deaths as rural

Question 12

Campi Flegrei, Italy

Answer 12

• One supervolcano caused large complex of 20 caldera craters, 100 sq km
• African plate subducting under Eurasian
• Continued monitoring»_space; hot magma detected below whole area
• 1m livng within the caldera»_space; eruption would be devastating

Question 13

Pompeii, Italy

Answer 13

• 79 A.D
• Estimated 2000 dead
• Buried under 25m of ash
• VEI 4
• Lack of knowledge»_space; no evacuation despite ash could & pumice falling hours before pyro flows