Tectonics Pack D

Question 1

What are the examples of primary social impacts of volcanic hazards?

Answer 1

• Death by asphyxiation, thermal injuries and trauma (91,000 killed from 1900 to 2016)
• Deaths (80% from 10 deadliest eruptions)

Question 2

What are examples of primary environmental impacts of volcanic hazards?

Answer 2

• Reshaping of the landscape by eruption, lahars and landslides
• Destruction of vegetation
• Changes to drainage patterns by lahars and landslides
• Increased precipitation due to released water vapour
• Reduction in temperature through ash clouds reducing incoming solar energy

Question 3

What are the examples of secondary environmental impacts of volcanic hazards?

Answer 3

• Emissions of greenhouse gases add to global warming
• Emissions of SO2 increase the risk of acid rain

Question 4

What are the examples of secondary social impacts of volcanic hazards?

Answer 4

• People left homeless (150,000 per year)
• Poor health from stress-related illness or spread of disease
• Lack of food due to drop damage and lack of clean water

Question 5

What are the examples of secondary economic impacts of volcanic hazards?

Answer 5

• Loss of income from destruction of farmland and businesses
• Financial loss from associated unemployment
• Financial loss from loss of primary activities (e.g. agriculture or forestry)
• Loss or damage to businesses
• Cost of clean up operations, repairs and rebuilding

Question 6

What was the background of the Tonga eruption?

Answer 6

• 15th January 2022
• VEI 5-6
• Underwater volcano (HTHH) in the Pacific Ring of Fire
• 1 in 1000 year eruption
• 100,000 population
• 170 volcanic islands

Question 7

What were the causes of the Tonga eruption?

Answer 7

• Convergent destructive boundary
• Composite volcanic
• Phreatomagmatic eruption (interaction with water created gas rich magma)
• Displaced seawater caused a tsunami
• Tsunami travelled further and faster due to Lamb waves coupling with ocean

Question 8

What were the events in the Tonga eruption?

Answer 8

• Eruption column was 57km (into mesosphere)
• Caldera dropped to -850m
• Tsunamis waves of 10-20m hit land with 90m initial waves
• 1.9km2 material ejected
• Tsunami across the Pacific Ocean

Question 9

What were the social impacts of the Tonga eruption?

Answer 9

• 84% of Tonga affected
• 7 deaths across Tonga, Fiji and Peru
• Food insecurity and water contamination
• Respiratory problems from ash
• 600 homes destroyed

Question 10

What were the economic impacts of the Tonga eruption?

Answer 10

• $180 million in damage
• 85% of agricultural households affected – crop destruction
• 5 weeks offline due to damaged undersea cable
• Damaged infrastructure (e.g. roads, ports, schools)

Question 11

What were the environmental impacts of the Tonga eruption?

Answer 11

• 400,00 tonnes of SO2 released
• 146 million tons of water vapour released
• Cooling effect of -0.1°C in S hemisphere
• Water contamination from salt and ash
• Oil spill in La Pampilla refinery in Peru
• Destroyed coral reefs and fish

Question 12

What were the responses to Tonga ?

Answer 12

• Immediate evacuation
• Warnings across the Southern hemisphere
• $21.5 million in direct aid
• Water purification, tents, communication equipment, food
• Red Cross has supplies for 1200 households but was not sufficient
• Created a Recovery and Resilience Plan - $240 million
• Launched MACRES, an early warnings and report system

Question 13

What was the background of the Nevado del Ruiz eruption?

Answer 13

• In Colombia
• 13th November 1985
• VEI 3

Question 14

What were the causes of the Nevado del Ruiz eruption?

Answer 14

• Convergent destructive boundary
• Stratovolcano covered by ice
• Phreatomagmatic eruption

Question 15

What were the events in the Nevado del Ruiz eruption?

Answer 15

• Pyroclastic flow melted 10% of ice on volcano
• Caused a lahar travelling at 60km/h through existing river valleys

Question 16

What were the social impacts of the Nevado del Ruiz eruption?

Answer 16

• 23,000 deaths
• 8000 made homeless

Question 17

What were the economic impacts of the Nevado del Ruiz eruption?

Answer 17

• 3400ha of agricultural land lost
• Power lines destroyed which isolated Armero
• Services and businesses destroyed
• $1 billion in damages

Question 18

What increased vulnerability to the Nevado del Ruiz eruption?

Answer 18

• Evacuations were not enforced by mayor
• Warning signs from eruption were not heard as it was dark and poor weather
• Risks maps were not distributed and poorly drawn so people though they were in safe zones

Question 19

What were the responses to the Nevado del Ruiz eruption?

Answer 19

• Efforts took too long and were hindered by mud and destroyed roads
• 12 hours for first survivors to be rescued
• Not enough antibiotics so injured people died

Question 20

What was the background of the Nyiragongo eruption?

Answer 20

• In E African Rift Valley, DRC
• 22nd May 2021

Question 21

What were the causes of the Nyiragongo eruption?

Answer 21

• Continental divergent boundary
• Steep sided cinder cones and stratovolcano
• Lava lake fluctuates in size, depth and temperature

Question 22

What were the events in the Nyiragongo eruption?

Answer 22

• Effusive lava flow at 1km/h towards Goma (20km away)

Question 23

What were the social impacts of the Nyiragongo eruption?

Answer 23

• 32 deaths due to asphyxiation and accidents in evacuation
• 1700 homes destroyed
• 17 villages destroyed

Question 24

What were the economic impacts of the Nyiragongo eruption?

Answer 24

• Local markets closed reducing informal work

Question 25

What were the responses to Nyiragongo?

Answer 25

- 400,000 evacuated to shelters, host families or across border to Rwanda - Evacuation was difficult because of conflict, covid and extreme poverty - UN cut funds due to corruption - Improved response from 2002 where 250 died

Question 26

What was the background of the Hawaii eruption?

Answer 26

- Archipelago over a 320km hotspot - Kilauea - SE shore of Hawaii Island - Flows frequently so not considered a major hazard - 30th April 2018

Question 27

What were the causes of the Hawaii eruption?

Answer 27

- Pacific plate moving NW over Hawaiian hotspot - Crater floor collapsed after increased pressure - Shield volcano

Question 28

What was the monitoring in Hawaii like?

Answer 28

- Data from SO2 levels and thermal activity to forest eruption times - Raise alert levels depending on precision of forecast and risk

Question 29

What were the events of the Hawaii eruption?

Answer 29

- Effusive eruption - 24 fissures over 35km2 - Most destructive eruption in the last 200 years

Question 30

What were the social impacts of the Hawaii eruption?

Answer 30

- 700 structures destroyed - 48km of roads covered by lava - 3000 residents evacuated - Isolated without water or electricity

Question 31

What were the economic impacts of the Hawaii eruption?

Answer 31

- $800 million in damages - 20% of state’s crops destroyed - 45% decrease in tourism - Shut of geothermal power plant

Question 32

What were the environmental impacts of the Hawaii eruption?

Answer 32

-350ha of new land beyond old coastline - SO2 emissions led to acid rain - Increased ocean acidity damaged marine ecosystems

Question 33

What were the responses to the Hawaii eruption?

Answer 33

- Evacuation of residents- - Monitoring of volcano during its active period

Question 34

What was the background of the Lake Nyos disaster?

Answer 34

- In NW Cameroon - 21st August 1986 - Ancient volcanic caldera with water - Happened overnight

Question 35

What were the causes of the Lake Nyos disaster?

Answer 35

- Limnic eruption - CO2 accumulated in deep water (stratified water) - Mixing of deep sea CO2 due to disruption (e.g. seismic activity or landslides) - CO2 dissolved and formed bubbles - Rapidly escaped to form clouds of gas

Question 36

What were the events in the Lake Nyos disaster?

Answer 36

- Flow of CO2 travelling 25km at 100km/h

Question 37

What were the social impacts of the Lake Nyos disaster?

Answer 37

- 1750 people died due to suffocation

Question 38

What were the economic impacts of the Lake Nyos disaster?

Answer 38

- 3500 livestock died due to suffocation

Question 39

What were the environmental impacts of the Lake Nyos disaster?

Answer 39

- 1.6 million tons of carbon released

Question 40

What were the responses to the Lake Nyos disaster?

Answer 40

- Degassing system installed to release CO2 from bottom of the lake - Reduces the risk of a large scale disaster again

Question 41

What was the background of the Soufriere Hills eruptions?

Answer 41

- In Monserrat, Caribbean - Period of activity started in 1995 for 20 years after 300 year of dormancy - Limited initial knowledge of volcanoes - April 1996

Question 42

What were the causes of the Soufriere Hills eruptions?

Answer 42

- Convergent destructive plate boundary of Atlantic and Caribbean plates - Volcanic dome formed from build-up of andesitic lava - Changes shape and explosions, earthquakes or rain can cause collapse

Question 43

What were the social impacts of the Soufriere Hills eruptions?

Answer 43

- 20 deaths in 1996 - No clear guidance on risks so people got too close - Plymouth buried by debris/lava - Population reduced 75% after relocation - Living in shelters for 10 years

Question 44

What were the economic impact of the Soufriere Hills eruptions?

Answer 44

- Bellum Valley golf course destroyed by lahars - Clogged machinery engines

Question 45

What were the environmental impacts of the Soufriere Hills eruptions?

Answer 45

- Vegetation and farmland destroyed by pyroclastic flows, lahars and ash - Declining mountain chicken frog numbers - Acidification of water and coral covered from ash - Competition between wild and feral animals - Farms and houses in exclusion zones - Acid rain from hydrogen sulfide and sulfur dioxide - Coast extended by 300m

Question 46

What were the responses to the Soufriere Hills eruptions

Answer 46

- Zoning system changed multiple times - Illegal to go in exclusion zones - Evacuation of 2/3 of island’s population in 1996 - Houses and community centres used for prisons and government departments - Relocation to UK - Temporary shelters in camps, churches and schools - £25 million a year from British government to rebuild economy

Question 47

What was the monitoring like in Montserrat?

Answer 47

- Roadblocks to reduce risk exposure - Zoning and levels for future evacuation so people can live and work near volcano - Scientific monitoring on volcano

Question 48

What was the background on Iceland?

Answer 48

- Period of activity in April 2010 - Iceland is one of the most geologically active places in the world - 1/4 of country is the 30 volcanic systems

Question 49

What was the background on the E15 eruption?

Answer 49

- 2010 - Along Mid Atlantic ridge - VEI 3 in April

Question 50

What were the causes of the E15 eruption?

Answer 50

- Constructive plate margin of N American and Eurasian plates - Phreatomagmatic eruption as located below a glacier

Question 51

What were the events of the E15 eruption?

Answer 51

- GLOF - 9km ash plume

Question 52

What were the social impacts of the E15 eruption?

Answer 52

- Destroyed roads, bridges and infrastructure - Local water supplies contaminated with fluoride - Cancelled sporting event

Question 53

What were the economic impacts of the E15 eruption?

Answer 53

- Grazing land destroyed - Geothermal water system and HEP plants damaged - Clogged machinery - 100,000 flights cancelled/rerouted - No fly zone meant airlines lost £130 million per day

Question 54

What were the environmental impacts of the E15 eruption?

Answer 54

- Glacier won’t ever recover - Animals left behind - Weather patterns blew ash towards Europe - Ash blocked sun - Flooding

Question 55

What was the preparation like for the E15 eruption?

Answer 55

- Well trained team and high quality equipment - GPS monitors detected ground deformation - 1000 people evacuated in 30mins to 4 safe zones - Ash modelling helped local evacuation decisions

Question 56

What were the responses to E15?

Answer 56

- Evacuation of area around volcano - European Red Cross Societies mobilised volunteers and staff - Masks worn to prevent choking on ash - Provided food, counselling, psychological support - 700 were evacuated from disaster zone three times over past month - Developed a new structure for air traffic management called Functional Airspace Blocks (FABs) - Levees utilised and debris removed from flood routes