Super Volcanoes

Super Volcanoes

Saturday, August 11th, 2012

There is no proof or evidence that any ancient civilizations would have been able to estimate volcanic eruptions hundreds or thousands of years in the future. However, there are super-massive volcanic calderas around the world, and they could erupt at some point in the future. Therefore it is important to be aware of the risks.

What is a Super Volcano?

A super volcano is simply a very large volcano that can have massive, deadly eruptions. While there is no accurate statistic used to classify a volcano as “super”, the phrase is used to explain a volcano that can jeopardize the globe. A super volcano will either greatly disrupt society or destroy all of humanity. Allow rare and uncommon, a super massive volcanic eruption is on par with the calamity endured from that of an asteroid impact.

Supervolcanoes are generally grow in pressure and size, and prepare to erupt over long periods of time.  In fact, there has never been a super volcanic eruption in human history. They appear less regularly than other volcanoes, but when they do appear, they are considerably more extreme. They are unusual enough to be forgotten from modern history, and we only know they have ever happened because of geological evidence from thousands of years ago.

Super Volcano Eruptions Throughout History:

These are the biggest supereruptions we are aware of. They all have a Volcanic Explosivity Catalog rating of 8 (VEI-8) which indicates they have exploded out at least 1,000 km³ of ejecta. The amount of ejecta is the most important requirement with regards to danger and disruption to weather cycles. Smaller disasters such as earthquakes and hurricanes are generally not powerful enough to impact our ongoing everyday living, but the amount of ash and debris in the atmosphere can block out the sun and have long-lasting effects on the weather.

These are the largest super-volcano eruptions believed to have taken place throughout history:

  • 26,500 years ago – Lake Taupo, NZ – 1,170 km³
  • 74,000 years ago – Lake Toba, Sumatra – 2,800 km³
  • 254,000 years ago – Whakamaru, NZ – 1,200-2,000 km³
  • 640,000 years ago – Yellowstone, USA – 1,000 km³
  • 2.1 million years ago – Yellowstone, USA – 2,500 km³
  • 2.5 million years ago – Cerro Galan, Argentina – 1,050 km³
  • 4 million years ago – Atana Ignimbrite, Chile – 2,500 km³
  • 4.5 million years ago – Yellowstone, USA – 1,800 km³
  • 6.6 million years ago – Yellowstone, USA – 1,500 km³
  • 27.8 million years ago – La Garita Caldera, USA – 5,000 km³
  • 29.5 million years ago – Sam Ignimbrite, Yemen – 5,550 km³

As a comparison of how large these super-eruptions really were, Mount St. Helens erupted just 1.2 km³ of ejecta, and the largest volcanic eruption in human history, Krakatoa, erupted a volume of 25 cubic kilometers.

How Devastating Can a Supervolcanic Eruption Really Be?

The supereruption of Lake Toba in Sumatra 74,000 years ago triggered a drop in worldwide temperatures by about 6 degrees Fahrenheit around the world on average, and as much as 18 degrees in some locations. Nearly 90% of animal populations were killed and as much as three-quarters of all plants in the north hemisphere died. Geologists discovered that volcanic ash following the eruption blanked parts of the earth by as much as 20 inches in some places.

The eruption of Tambora Mountain in 1815 was mild in comparison to a super-eruption, but is an example of the problems we could encounter from a much larger eruption. It ejected over 36 cubic kilometers of ash and rock into the atmosphere, reaching as high as 30 kilometers. This debris drifted around the world, greatly impacting the weather above both European countries and the USA. Many locations experienced their coldest winter weather in history. There were food shortages, riots, and civil unrest around the world. Ireland was toughest hit, where the starvation led to an outbreak of typhus, infecting 1.5 thousand individuals and killing over 65,000. The 1815 eruption cause a mini ice age, and some normally mild climate regions experienced snowfall in the summer months.

The infamous Krakatoa eruption of 1883 triggered a sequence of tsunamis, some as high as 100 ft. tall, which killed thousands of individuals in the region. The eruption was so large and deafening that it could be seen and felt over 3,000 kilometers away.

These large eruptions in recent history have greatly effected the weather and planet. However, these eruptions are tiny in comparison to a super-volcanic eruption, like that which may happen at Yellow Stone.

Extreme changes in weather patterns and rainfall would undoubtedly cause crops to fail, livestock to die, and a food shortage around the world.

This map reveals historical ash fall patterns from the last three volcanic eruptions of Yellowstone:

Yellowstone Super Volcano

There are only about 50 supervolcanoes that have ever existed on planet earth, and most of these are now extinct or thought to be dormant. There are however still several active super calderas that may be threats to our existence if they were to ever erupt. These are the most threatening, both in size and their location.

  • Lake Toba in Sumatra, Indonesia erupted 74,000 years ago. It is believed to be the largest volcanic eruption on Earth within the past 25 million years. Most early humans, plants and animals did not survive.  Toba is currently classified as active, although it has seen little activity within the last couple of hundred years.
  • Yellowstone in the Yellowstone National Park of USA most recently erupted about 630,000 years ago. Scientists have estimated that the energy of the eruption is equivalent to force of 1,000 Hiroshuma atomic bombs exploding every second. Due to its central location in the U.S., a super eruption here would devastate the world.
  • Long Valley in California, USA last erupted 760,000 years ago and is still considered to be active today. Over 600 cubic kilometers of rock and ash were ejected during the last eruptions.
  • Valles Caldera in New Mexico, USA – last erupted about 1.15 million years ago. It is thought to be dormant, but some researchers speculate that it is still in an active, but sleeping state. Evidence suggests that nearly 600 cubic kilometers of ejecta was emitted during the most recent eruption.
  • Phlegraean Fields Volcano in Naples, Italy erupted about 39,000 years ago, releasing over 500 cubic kilometers of rock and ash.
  • Lake Taupo in New Zealand erupted only 26,500 years ago. This is the most recent “supervolcano” to erupt, and has had smaller eruptions every thousand or so years ever since. The most recent eruption was 1,800 years ago, and is considered the largest in recorded history, at over 100 times larger than the Mount St. Helens eruption.

All of these super-massive calderas are still considered to be active volcanoes and could erupt again in the near future. These are huge, rare events in terms of human history. The best way to prepare for such a catastrophe is to stock pile food, water, medicine and survival supplies to ride out any disasters and impending aftermath.

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