Transcript volcanoes - an-0001

what is a volcano?
• Volcano is a cone – shaped mountain
explodes and lava comes out.
• The solid ground that we walk on is part of
the earth’s crust and below this crust lies a
hot layer knows as magma.
• When magma explodes through an
opening in the earth’s crust and a volcano
erupts.
How are volcanos formed?
• Volcanoes are formed when a hot magma
pushes to go to the earth’s crust.
• Earth’s crust is separated into different
pieces known as tectonic plates.
• These plates fit right together like a giant
jigsaw puzzle.
Eruptions! Why do they erupt?
• As magma rises, gases expand and the
water becomes steam.
• This creates a huge pressure and when
the pressure becomes too great, a volcano
erupts with a boom.
• Eruptions can be formed from gentle
oozing and then to violent explosions.
After the eruption.
• The volcano ashes are deadly it is hard
and abrasive, like finely crushed glass.
• Gases spewed out from volcanic eruptions
such as carbon dioxide and sulphur
dioxide, are more deadly.
• Devastating mudflows, known as lahars,
are caused by ashes, soil and rock
combining on volcanic slopes.
Types of volcano!
• There are three main types of volcanoes
and it is composite, shield and cinder
cones.
• Composite volcanoes are formed by layers
of lava and rock fragment.
• Cinder cone volcanoes erupt but don’t
produce much lava.
• Shield volcanoes erupt every few years,
they create lava flows and fire fountains.
Types of erupting.
• Volcanoes can erupt in different ways.
• This also affects the surrounding
landscape and its people.
• Pompeii was buried by the eruption and
killed more than 2,000 people.
• Pompeii was buried for over 1500 years.
Mt. St Helen
• In 1980 on the 18th of May, Mt St Helen in
Washington state, USA, erupted.
• The explosive eruption lasted for nine
hours and resulted in the death of 57
people.
• The number of trees blown down by the
lateral blast of the eruption could have
built 300,000 homes.
Volcanic landscapes
• Areas around volcanoes are called
geothermal regions.
• Geyser are hot spring erupting from vents
in the ground.
• The word ‘geyser’ comes from Icelandic
region and means to ‘rush forth’ or ‘to
gush’.
Living with volcanoes!
• All around the world people and volcanoes
exist side by side.
• Through volcanoes pose a threat, living
near volcanoes also provides advantages.
• In 1992 an eruption of Mt. Etna threatened
to bury the village of lava.
Working with volcanoes.
• Volcanologists are scientists who study
volcanoes.
• They try to find out how volcanoes form
and predict when they might erupt.
• Scientists cannot prevent volcanoes from
erupting.
• Seismographs measure tremors in the
Earth, which help scientist predict when a
volcanoes might erupt.
Bibliography
• My bibliography was a book about
volcanoes from school.
• My other bibliography was Google,
Wikipedia, Bing and encyclopedia.
• I also got some information of a book
called volcanoes but talks about Mt St
Helens.