Please enable JavaScript.
Coggle requires JavaScript to display documents.
Detailed specific example: Tonga - Coggle Diagram
Detailed specific example: Tonga
Brief information
December 2021, a submarine volcano in Tongan islands erupted
Island increased by 200-600 metres on eastern side
January 15 2022, next explosion
5.7 on Volcanic Explosivity Index
Largest atmospheric explosion recorded by modern instruments
10km³ of material displaced and 140 megatons of water vapour ejected
Volcanic islands lie along a subducting plate boundary
Pacific plate subducting beneath the Indo-Austrailian plate
Causes
Magma inside the volcano under enormous pressure
Shifting Earth pulled surrounding sea water into subduction zone
Seawater met hot magma, boiled, and added water vapour and other gases to magma chamber
Rock fracture under the pressure, gas expanded, blasted the magma apart
Massive eruption, sent a plume of material 58km into atmosphere
Crater located 200 metres below sea-level
Water poured into volcano and turned the water into steam
Increasing expansion of the eruption
The impacts of the eruption
Social and economic
4 people on the islands died whilst several were injured
Flooding and damage to properties on the islands from the Tonga tsunami
Total economic cost caused: $182 million
Air traffic was interrupted as it wasn't safe, they were allowed back 5 days later, once the ash was mostly gone
Communication channels damaged, restored 5 days later
Environmental
Large amounts of water vapour produced
Ejected into the atmosphere
Water vapour is a greenhouse gas
The ash created acid rain and acid gas, affecting the surface water and groundwater
The acid can cause long-lasting damage to coral reefs and disrupt the life cycle of aquatic organisms
Iron added from the magma to the water, affecting the food web
Triggers growth of blue-green algae and sponges
Positive impacts is the addition of nutrients ash to the soils
Increases soil fertility and supports plant growth
Increases habitat availability for terrestrial organisms
Volcanic
Tsunamis around Pacific basin
Affecting Far Eastern Russia, Chile, and Peru
Tsunamis in Tonga up to 15m high
Atmospheric shockwaves that moved around the planet, causing damage on distant coastlines
Responses to the eruption
Immediate response
15-17 January 2022
People urged to stay indoors to avoid the ash
Can irritate eyes or cause medical conditions e.g. asthma and bronchitis
People advised to prevent contamination of freshwater storage with sulphur dioxide by covering rainwater tanks
Drinking water also became more acidic with time
20 January 2022
20 January 2022
First aid planes from New Zealand and Australia arrived
Phones were partially restored
15 January 2022
Tsunami warning issued for people to move away from coastlines, low-lying areas were evacuated
2 February 2022
2 February 2022
Once aid shipments were received, the country went into COVID-19 lockdown as two port workers tested positive
14 January 2022
Tsunami warning issued for people to move away from coastlines
International assistance
New Zealand
Provided desalination equipment to produce fresh water
Austrailia
Carried out surveillance flights to assess damage
New Zealand, Chine, the USA, etc
Provided relief supplies to Tonga to assist with reconstruction
Engineers helped restore internet access and restore communications
France, the USA, Australia, and New Zealand
Co-ordinated humanitarian aid
Early warnings
December 2021
The Tongan government notified the population of increased volcanic activity
Managing the impacts of eruptions in Tonga
Prediction and monitoring
Hazard mapping
Maps areas at highest risk of tsunamis, earthquakes, and ash fall
Island chains constantly observed
For change in volcanic and seismic activity
Funding through the Climate Risk and Early Warning Systems initiative
Ensures faster and broader warnings across the island chain
Planning and protection
Well-developed emergency plans and briefing of the community.
Stores of items like food, water, shelter, clothing, and medical resources for response in the event of an eruption
Developed evacuation routes and plans for low-lying areas and islands.
