tectonics

• Tonga volcanic eruption -2022 -

  • on Tonga ridge formed by convergent boundary where pacific plate is subducted by the indo-australia plate - forming long, volcanic island chain
  • volcano consists of 2 uninhabited islands
  • pokes up 100m above sea level and is 20km wide
  • underwater volcano
• Tonga volcanic eruption: details -

  • underwater eruption triggered a tsunami and covered many of tongas islands in a thick layer of volcanic ash
• Tonga volcanic eruption: social impacts -

  • residents struggled to breathe due to ash in the air
  • 600 buildings including 300 homes damaged
  • 4 deaths
  • blanket of thick ash contaminated water supplies, cut off all communication and prevented surveillance flights (made it difficult for relief efforts)
  • deaths reported in Peru and California due to swell and storm surges from the tsunami
• Tonga volcanic eruption: economic impacts -

  • fishing boats, local schools and infrastructure were destroyed
  • damaged to underwater cables meant that communications were suspended and internet service was unavailable for 2 weeks after
  • local businesses were destroyed
  • world bank assessed damaged at a cost of $90.4 million
  • further impacts in Japan - number of fishing boats were capsized or lost to sea
  • domestic flights by Japan airlines were cancelled due to volcanic ash in the air
  • tsunami storm surge caused damage to Santa Cruz harbour in California
• Tonga volcanic eruption: Environmental impacts -

  • energy released from volcano was equivalent to 100 Hiroshima bombs
  • off coast of Peru there was an oil spill as the tsunami waves disrupt a ship transporting oil - affecting the surrounding sea, beach and protected natural areas
• Tonga volcanic eruptions: emergency responses -

  • Tonga Red Cross staff and volunteers assisted in helping the community - providing drinking water, temporary shelters across the countries many islands
  • royal New Zealand air force flew to Tonga to provide vaccines, PPE and rapid antigen tests to support tongas covid 19 response - flew in technicians and equipment to restore communication links
  • country received $8 million in emergency funding
• Tonga volcanic eruptions: long-term responses -

  • improved its resilience to natural disasters by creating the 'disaster risk financing strategy' - promotes risk reduction and preparedness
  • program included reforms to fiscal stability, climate and disaster resilience, employment opportunities and financial sector development
  • world bank donated $19 million to support program
• nepal earthquake 2015 -

  • 7.8 magnitude
  • nepal sits right on boundary between the Indian and eurasian convergent plates - push against each other before a sudden release of pressure
  • epicentre located 80km northwest of Kathmandu - depth of 15km
  • initial earthquake and its aftershocks killed a total of 8633 - injured 21,000 - 3 million people made homeless
• nepal earthquake 2015: vulnerability and effects

  • occurred at midday - most people at work (many tending fields) - helped to reduce death toll - many returned to damaged or destroyed homes
  • fairly low population density - did affect capital Kathmandu - most damage was rural areas
  • vulnerable country - in 2016 it was 197th/229 countries for GDP per capita - unprepared
  • weak infrastructure - bridges, roads, safe water - severely damaged or destroyed
  • many large aftershocks and nearly 100 smaller ones
  • mountainous - created landslides - cut rural areas off - made rescue and aid difficult
• nepal earthquake 2015: vulnerability and effects -

  • emergency services not able to cope - relied on international aid agencies for help
  • tourism fell significantly - loss of much needed income
  • economy is estimated to have lost US$5 billion - 25% of its gross domestic product
  • US$6.6 billion needed for rebuilding work
• Iceland Eyjafjallajokull volcano 2010 -

  • eruption causing a spreading ash cloud across Europe
  • 100,000 commercial flights were canceled worldwide
  • 10 million passengers worldwide were stranded or unable to board flights travelling either to or from Europe
  • worldwide airlines lost US$1.7 billion in revenue
  • 30% of global airline capacity was cut - Europe 75%
  • european economy lost US$5 billion as a result from disruption
  • effected Kenya - 20% of economy is based on green veg and flowers mainly to Europe - when cancelled businesses forced to dump them - costing US$1.3 million a day
• Montserrat volcano 1995 -

  • island arc in Caribbean Sea
  • formed where Atlantic plate subducts beneath Caribbean plate
  • only 16km long and 10km wide - consists almost entirely of volcanic rock
  • began to erupt huge clouds of ash - over next 5 years eruptions continued - pyroclastic flows affecting much of island
• montserrat volcano 1995: consequences -

  • dozens of people lost their lives - more than 7000 people moved to other countries (orignially 11,000 residents)
  • capital Plymouth was destroyed - contained islands main services (eg government offices and hospitals)
  • 2/3 of all houses and 3/4 of infrastructure destroyed
  • unemployment rose as islands tourism industry collapsed
  • lot of farmland was destroyed or abandoned - severely affected agriculture
  • created a top-heavy population pyramid - younger people no longer saw economic future on island
• indian ocean tsunami 2004 -

  • rates as one of the worlds worst human disasters
  • earthquake off coast of Sumatra Indonesia caused it - 9/9.3 magnitude - thrust heaved floor of Indian Ocean towards Indonesia by about 15m and sent out shock waves - radiated as 'ripples' unnoticed until they hit land
  • struck shallow coastline near Banda ache (only 15mins from origin)
  • nearly 17m high on impact
• indian ocean tsunami 2004: affects -

  • affected countries around the entire span of the Indian Ocean - from Indonesia to South Africa
  • 5 million people affected
  • nearly 300,000 died
  • 1.7 million people left homeless
• indian ocean tsunami 2004: why it was so destructive -

  • earthquake that caused tsunami was especially large
  • epicentre close to densely populated coastal communities - no time to react
  • low lying coastlines of many indian oceans countries and islands meant tsunami waves able to travel several km inland
  • no early warning system
  • many countries low income - no resources to spend on tsunami protection
• indian ocean tsunami 2004: impacts -

  • in some coastal villages 70% of villagers killed
  • in sumatra 1500 villages completely destroyed
  • Sri Lanka - more than 60% of fishing fleet and industrial infrastructure was destroyed
  • thailand tourism industry - lost US$25 million a month and 120,000 workers lost jobs
  • ecosystems (mangroves, coral reefs, forests and coastal wetlands) severely damaged
  • most vegetation and topsoil removed up to 800m inland
  • freshwater and agricultural soil contaminated by salt water
  • overall economic cost came to over US$10 billion
• Haiti 2010 earthquake -

  • magnitude - 7.0
  • number of dead or missing - 250,000 - 316,000
  • injuries - 300,000
  • homeless - 1.3 million
  • economic cost - US$14 billion
  • GDP per capita - US$1300
  • type of economy - developing
• china (Sichuan) 2008 earthquake -

  • magnitude - 7.9
  • number of dead or missing - 87,000
  • injuries - 375,000
  • homeless - 5 million
  • economic cost - US$125 billion
  • GDP per capita - US$6600
  • type of economy - emerging
• Japan 2011 earthquake/tsunami -

  • magnitude - 9
  • number of dead or missing - 19,800
  • injuries - 6,065
  • homeless - 130,900
  • economic cost - US$240 billion
  • GDP per capita - US$39,400
  • type of economy - developed
• Haiti 2010: physical factors -

  • located on a fault between North American and Caribbean plates
  • struck near capital
  • shallow focus (13km)
  • liquefaction on looser soil caused many building foundations to sink
  • epicentre was only 24km from Port au Prince - capital and most densely populated city
• Haiti 2010: political, social and economic factors -

  • developing country - poor + limited resources being spent on more immediate issues eg disease
  • high level of corruption at national + local government level led to lack of resources + commitment to improve country's infrastructure + living standards
  • lack of building controls and regulations - many houses in capital were poorly built slum housing - couldn't sustain shaking and collapsed - difficult for rescue teams due to dense urban
  • lack of disaster prep meant government officials, police and emergency services didn't know what to do
• Haiti 2010: impacts -

  • only one airport, several ports and few main roads - when damaged crucial aid supplies prevented from arriving or being distributed effectively - slow down rescue - more deaths
  • quarter of government officials killed - key government buildings destroyed - less able to organise recovery and relief
  • October 2010 - outbreak of cholera - lack of medical supplies and trained healthcare workers caused disease to spread - by 2015 over 9000 deaths and 720,000 affected
• Haiti 2019: recovery -

  • 5 yrs after - still recovering
  • internationally US$13 billion of aid donated - most remained with international organisations
  • concerns of political corruption meant organisations unwilling to channel money directly through Haitian government - managed themselves - hampered Haitis ability to become self-sufficient - needed money not gone to local businesses + industries
  • 2015 80,000 Haitians still living in temporary housing or camps
  • new buildings, roads and schools built and health statistics improved
  • government getting stronger + more able to cope with threats
• china 2008 -

  • struck Sichuan - mountainous region in south-west china