Super Volcanoes

• Super volcano


  A volcano that erupts more than 1000km3 of material in a single eruption
• Super volcanoes


  • Exist in giant calderas
  • The Yellowstone super volcano in Wyoming has a volcano measuring 75km in diameter
• Super volcanoes active in the last 2 million years


  • Yellowstone
  • Long Valley in eastern California
  • Toba in Indonesia
• The most recent super volcanic eruption occurred at Taupo, North Island, New Zealand


  27,000 years ago
• VEI


  Volcanic Explosivity Index - super volcano eruptions are an 8
• Impact of super volcanic eruptions

  Deduced from the extent and depth of ash layers and their impact on plant, insect and animal species (palaeobiology)
• The eruption of Toba approximately 74,000 years ago caused a population bottle neck
• Yellowstone super volcano


  Located in the USA in the state of Wyoming
• Volcanic activity at Yellowstone

  1. Began about 2 million years ago when a giant caldera formed

  2. Two further huge eruptions took place 1.3 million years ago and 640,000 years ago

  3. Dozens of smaller eruptions have occurred
• The evidence of earlier eruptions may have either been buried or destroyed by the later ones, so it is not known exactly how often the volcano has erupted or the volume of the material extruded
• During the largest eruption at Yellowstone, ash was spread over much of the western half of North America while gasses and tiny particles were carried around the globe in the upper atmosphere
• It is likely that this caused a noticeable though temporary decrease in global temperatures
• Misconceptions about Yellowstone super volcano

  • Yellowstone is overdue a high magnitude event
  • When Yellowstone erupts it will have severe global consequences
  • The Yellowstone magma chamber is growing
  • The caldera surface is rising
• Tectonic events do not follow regular patterns making accurate and reliable predictions impossible. Furthermore, due to the long period of time between events we do not have enough data to be able to say for certain there's a specific reoccurrence time frame
• The most probable eruption will be a lava flow or hydrothermal event. These would have little impact outside the region
• There is no evidence of the growth in the near surface size of the magma chamber that would be required for an eruption
• Measurements have indicated both rises and falls in ground surface within the caldera. The latest research suggests volcanoes can display quite rapid ground movement without necessarily erupting
• Possible effects of a worst case eruption at Yellowstone


  • Over 100,000 people would be killed instantly due to the blast and pyroclastic flow - within 1000km 90% of the population could be killed
  • Most of North America would be completely uninhabitable
  • Crops and food supplies would suffer greatly, and prices would increase dramatically. Global famine and mass starvation would be inevitable
  • Water supplies would be contaminated
  • Respiratory and general health problems would increase
  • Ash thrown into the upper atmosphere will circulate around the globe and cause a 'dark summer` where no sunlight would get through for at least a year
  • Global temperatures would drop by at least 3-5oC and remain low for many years. Depending on the drop it could trigger and ice age
  • Buildings would be crushed by the ash fall
  • The Global economy would collapse
• In 2012 the UN estimated that food resources would last 74 days in the event of a worst case Yellowstone eruption