Volcanic Eruptions

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Soufriere Hills - 1995-1998 - General Information

Why Is There A Volcano Here?

  • Volcano on the island of Montserrat, in the Caribbean sea
  • On the Antilles volcanic arc, it is above the subducting North American plate
    • The sediments and water in the crust mean it has a lower density when it melts so it rises to the base of the crust and creates a volcano.

Background Information

  • Previously the island occupied 11,000 people.
  • The volcano had lain dormant for 400 years previous to th eruption.

The Eruption

  • Earthquake swarms detected
  • Pyroclastic flows covered the Tar River valley and created a new delat when they reached the sea.
    • (Pyroclastic flow also destroyed Plymouth (capital city) SW of island and Bramble airport.)
    • Lahars slowly covering Plymouth
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Soufriere Hills -1995-1998- Impacts and Responses

Responses

  • Plymouth abandoned in 1996
  • Exclusion zone expanded in 1997 and residents advised to wear helmets and masks outdoors
  • Residents told to move north, 5000 now in shelters,  August 1997
  • In 1997, th eBritish Government offered £2400 to each adult to help with relocation
  • Development of Little Bay Port to replace Plymouths facilities
  • Conversion of St Johns Hospital to main island hospital
  • Improving air access

Impacts Of The Eruption

  • 2/3 of the islanders have left the island, 8000 people
  • Collapse of the tourist and rice industry
  • Unemployment has risen from 7% to 50%
  • Respiratory problems caused by the ash
  • Skill shortage due to the number of people that left the island
  • 70% rise in rent for accomodation
  • 19 died in total
  • Pyroclastic flows incinerate organic material as well ash covering them
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Nyiragongo - Jan 2002 - General Information

Why Is There A Volcano Here?

  • Positioned on the Great African Rift Valley where plates are diverging from eachother
  • The eruption was caused by a shift in the plates opening up a 3km fissure on th esouthern flank of the volcano

Background Information

  • The volcano is north of the city of Goma in the East of the Democratic Republic of Congo
    • Very far from the capital Kinshasa
    • On the border of Rwanda and Uganda
    • Population of Goma is 1 million
  • Equipment stolen from observatories by rebels, meant scientists weren't observing the volcano

The Eruption - January 2002

  • A 13km fissure opened up which poured out lava flowing at an incredible 60mph
  • Earthquake accompanying the eruption was 5 on the Richter Scale
  • 7000 tonnes of sulphur dioxide emitted each day by the volcano
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Nyiragongo - Jan 2002 - Impacts and Responses

Responses

  • Religious beliefs meant people were reluctant to leave, believing they wouldnt be punished
  • Mixed messages were given, people told to stay and leave by different people.
  • Half a million people left Goma, lots settled in the jungle in Rwanda
  • Within a week, most people had had to return to Goma to collect aid
  • Oxfam tried to deliver 15 litres of clean water to each person
  • An armed guard now travels with the vulcanologists to protect them from the rebels
  • Children are educated to prepare them for future eruptions

Impacts

  • The airport was cut in two by lava flows
  • Lava cooled leaving rock as much as 3 metres deep
  • The ground became more fertile due to the new layers of ash
  • 147 people died in the eruption
  • 1/3 of Goma was destroyed by the lava flows
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Eyjafjallajokull - 2010 - General Information

Why Is There A Volcano Here?

  • Iceland lies on a divergent plate boundary

Background Information

  • There are peaks in Icelandic volcanic activity every so often, currently experiencing one
    • Katla volcano in Iceland, much bigger than E15 and predicted to erupt soon
      • 10km wide caldera, 750m of ice on top
  • The lava was very basaltic menaing the eruption was explosive
  • Icelandic people are very aware of the imminence of future eruptions and aren't afraid because they know how to deal with them (synopticity)

The Eruption

  • The glacier on top of the volcano meant the ruption was a lot worse
    • The way the melted water mixed with the lava and created huge amounts of ash
  • A fissure opened up, 150m in length, launching 1000 degree C lava up to 150m in the air
  • A normal supply of lava lasts for a couple of days, although magma left from an eruption in 1821 meant there was months supply of lava.
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Eyjafjallajokull - 2010 - Impacts and Responses

Reponses

  • 500 farmers were evacuated overnight.
  • Airports in northern and western Europe were shut down for 6 days, costing £1.2bn.
    • Impacted apporximately 10 million travellers
  • Icelandic people are preparing for future eruptions that will be even bigger
  • Local people were advised to use ags masks and helmets

Impacts

  • Kenyan flower industry was impacted costing producers between £1.5m and £2m a day.
    • (Planes weren't able to fly out the flowers to Europe)
  • A thick layer of ash fell on nearby pastures of Raufarfell, 5cm fell
    • This became wet and thick and made it difficult to farm
  • River levels rose as part of the ice cap melted, this disrupted roads and damaged bridges
  • Local people living close, are suffering from respiratory issues
  • New born lambs killed due to ash in their lungs
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Mount Aso - Sept 2015 - General Information

Why Is There A Volcano There?

  • Japan has approx. 108 active volcanoes
  • It is on the main southern island, Kyushu in Japan, on an island arc
  • It is between the Phillipine, Eurasian and Pacific plates on a convergent plate boundary

Background Information

  • Mount Aso is a popular tourist destiation
  • Not many people living near to the volcano
  • In 1953, 6 tourists were killed in an eruption

The Eruption

  • An ash cloud was sent up 2000 metres
  • There was no warning of the eruption
  • Parts of the ash cloud collapsed into several pyroclastic flows
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Mount Aso - Sept 2015 - Impacts and Responses

Responses

  • People were banned from going near the site, 30 people evacuated
  • Cancelled at least 24 flights from Kumamoto airport
  • A 4km wide area was closed around the crater
  • Danger level increased to 3 out of 5
  • There was an immediate eruption warning once people knew it was erupting

Impacts

  • Ash fell as far as 4km away from the crater
  • No reports of injuries 
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