VOLCANOES

1
VOLCANOES
2
This presentation will be about volcanoes and
previous eruptions.
3
What Causes Volcanoes

• Inside the earth's core there is a red-hot liquid
  rock, called magma. Volcanoes happen when magma
  rises to the surface of the earth, which causes
  bubbles of gas to appear in it. This gas can
  cause pressure to build up in the mountain, and
  it eventually explodes. When the magma bursts out
  of the earth, it is called lava.

4
Are there different types

• The type of magma in the earth can create
  different volcanoes. If the magma is quite thin,
  the gas can escape easily and there will not be
  an explosion. The magma just comes out of the
  mountain and flows down the sides, like Volcanoes
  in Hawaii and Mount Etna. But, if the magma is
  thick and sticky, the gas cannot escape, so it
  builds up and up until it explodes. This can
  cause landslides and sends out huge clouds of
  burning rock and gas, which devastate everything
  around them, like the famous eruptions at Mount
  St Helens and Montserrat.

5
What effects do they have

• Volcanoes can change the weather. They can cause
  rain, thunder and lightning. Volcanoes can also
  have long-term effects on the climate, making the
  world cooler. Fast-moving lava can kill people
  and falling ash can make it hard for them to
  breathe. They can also die from famine, fires and
  earthquakes which can be related to volcanoes.
  People can lose their possessions as volcanoes
  can destroy houses, roads and fields. Lava can
  kill plants and animals too. The Mount St Helens
  volcano in 1980 killed an estimated 24,000
  animals including 11,000 hares, 6,000 deer, 300
  bobcats, 200 black bears and 15 mountain lions.

6
Can you predict them

• Scientists who specialise in volcanoes are called
  volcanologists. They are getting better at
  predicting volcanoes. The most reliable method is
  listening to the 'rumbles' inside a grumbling
  mountain. They also look at the changes in the
  gases which come out of volcanic mountains, the
  angle of the slopes, and bizarrely, the behaviour
  of animals in the area. Animals often seem to be
  able to 'detect' when an eruption is coming, and
  they become agitated and worried.

7
Do they do anything good

• Volcanic ash is very good for soil, so plants
  grow quickly and strong after a volcano. Volcanic
  slopes left after an eruption are very steep, so
  rare and delicate plants and animals can set up
  home there and be protected.

8
Volcano Facts

• One in 10 people in the world live within 'danger
  range' of an active volcano.
• There are around 1510 'active' volcanoes in the
  world. Volcanologists disagree on what comes
  under the term 'active', but 1510 volcanoes have
  erupted in the last 10,000 years, which means
  they are active in the world of volcanoes. There
  are thought to be many more volcanoes on the sea
  bed.

9
Volcano Facts

• The biggest volcano in the world is Mauna Loa in
  Hawaii. Its whole volume is about 80,000 cubic
  kilometres.
• Sometimes lightning is seen in volcanic clouds.
  It's not clear why this happens but it could be
  to do with lots of hot particles bashing into
  each other, causing static charges.

10
This is a volcano which has erupted
11
This is the Etna Volcano, in Italy.
12
In mythology, Etna was identified as the location
of the forge of Volcan, home of the Cyclopses,
and where the giant Enceladus laid (eruptions
being his breath and earthquakes his motion).
Etna's beauty, frequent eruptions, and long
record of eruptions makes it one of the world's
best known volcanoes. With hundreds of papers
published on nearly every aspect of Etna's
geology it is probably one of the world's most
studied volcanoes.
13
THE END
14
GOODBYE