Transcript Effects of Volcanic Eruptions

Effects of Volcanic Eruptions
Key Concept: The affects of
volcanic eruptions can change
human and wildlife habitat.
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
• High in the atmosphere,
ash and gas spread
around Earth.
• The average global
temperature decreased
by as much as 3°C for
one to two years.
• The lower temperature
caused crop failures and
starvation, particularly in
New England and
Europe.
• 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.
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.
• Pyroclastic flows can burn everything in their
path.
• Hot volcanic materials can melt the snowcap on
a mountain, causing devastating floods.
• 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.
Global Effects of Volcanic
Eruptions
• Large volcanic eruptions can affect Earth’s
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.
• 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
Earth’s 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.
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.
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.
• 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.
• 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.
• 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.
• 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.
• 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.
• Use these term to fill
in concept map.
eruptions
shield volcanoes
cinder cone volcanoes
composite volcanoes
lava