Effects of Volcanic Eruptions

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Effects of Volcanic Eruptions

• Key Concept The affects of volcanic eruptions
  can change human and wildlife habitat.

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Negative Effects of Volcanic Eruptions

• Volcanic explosions can have local and global
  effects.
• In April 1815, Tambora volcano in Indonesia
  erupted explosively.
• The pyroclastic flows and falling debris killed
  about 10,000 people in the area.

Crater
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• High in the atmosphere, ash and gas spread around
  Earth.
• The average global temperature decreased by as
  much as 3C for one to two years.
• The lower temperature caused crop failures and
  starvation, particularly in New England and
  Europe.

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• The effects of lower temperatures led to the
  deaths of about 82,000 people.
• Therefore, an estimated total of 92,000 people
  around the world lost their lives as a result of
  the Tambora eruption.

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Local Affects of Volcanic Eruptions

• Volcanic eruptions can cause loss of human life
  and loss of wildlife habitat.
• The blast from an explosive eruption can knock
  down trees, destroy buildings, and kill humans
  and animals.

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• Pyroclastic flows can burn everything in their
  path.
• Hot volcanic materials can melt the snowcap on a
  mountain, causing devastating floods.

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• Volcanic ash can mix with water to form
  fast-moving mudflows called lahars.
• The weight of falling ash can collapse
  structures, bury crops, and damage engines.
• Volcanic ash can also cause respiratory problems
  in humans.

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Global Effects of Volcanic Eruptions

• Large volcanic eruptions can affect Earths
  climate for several years.
• During large eruptions, ash and sulfur-rich gases
  can be pushed into the stratosphere.
• As the ash and gases spread around the planet,
  they absorb and scatter sunlight.

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• Enough sunlight may be absorbed or scattered to
  lower the average global temperature of Earth.
• In 1991, after the eruption of Mount Pinatubo in
  the Philippines, the amount of sunlight to reach
  Earths surface decreased by 2-4.
• This decrease caused the average global
  temperature of Earth to decrease by several
  tenths of a degree for several years.

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Benefits of Volcanic Eruptions

• Volcanic soils are some of the most fertile soils
  on Earth.
• Volcanic rocks are made of minerals that contain
  elements important to plant growth.
• When volcanic rocks break down, they form soils
  that contain many nutrients that plants can use.

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Geothermal Energy

• Magma heats the rocks that surround it.
• These rocks often hold water that also becomes
  heated.
• This heated water, called geothermal water, may
  reach temperatures of hundreds of degrees
  Celcius.

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• Geothermal water contains large amounts of heat
  energy.
• This energy can be tapped by drilling wells to
  reach the hot water.
• Water can also be pumped through heated rocks to
  obtain energy.

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• Geothermal water can be used to drive turbines
  that generate electricity.
• It can also be used to heat homes, grow crops, or
  keep roads free of ice.

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• Volcanic rocks are often used in construction.
• As early as 300 BCE, Romans made concrete from
  volcanic ash and lime.
• This material was used to build the Colosseum in
  Rome in 80 CE. The strength of this material has
  allowed the Colosseum to stand for nearly two
  thousand years.

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• As recently as the 20th century, volcanic ash was
  used to make concrete for dams in the United
  States.
• Today, basalt and pumice are often used in the
  construction of roads and bridges, and the
  production of concrete.

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• Pumice is added to soil to allow air and water to
  circulate more easily through the soil.
• Because metals in pumice are not water soluble,
  pumice is used alone or with silica sand to
  filter drinking water.

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• Use these term to fill in concept map.
• eruptions
• shield volcanoes
• cinder cone volcanoes
• composite volcanoes
• lava

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