"volcano explanation"
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Volcano Explanation
EXCHEL CORP
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VolcanoA volcano is a rupture on the crust of a planetary
mass object, such as the Earth, which allows hot lava,
volcanic ash, and gases to escape from a magma
chamber below the surface.
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Magma ChamberA magma chamber is a large underground pool of
liquid rock found beneath the surface of the Earth.
The molten rock in such a chamber is under great
pressure, and given enough time, that pressure can
gradually fracture the rock around it creating outlets
for the magma.
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LavaLava is the rock expelled from a volcano during an
eruption. When it first comes out, the lava can have a
temperature higher than 700 degrees C. It then flows
downhill from the eruption point until it cools and
hardens.
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Main VentA volcano’s main vent is the point in the Earth’s crust
where hot magma has reached the surface. The
familiar cone-shaped volcano builds up as ash, rock
and lava ejected during eruptions fall back to Earth
around the vent.
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CraterA volcanic crater is a circular depression in the ground
caused by volcanic activity. A volcano’s vents are
located at the bottom of the crater.
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Pyroclastic Flows Pyroclastic flows are fast moving currents of hot gas
and rock with travel down hill from a volcano,
reaching speeds of 700 km/hour. The gas can reach
temperatures of more than 1,000 degrees C, and is
one of the greatest dangers from volcanic eruptions.
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Ash Cloud Volcanic ash consists of small pieces of pulverized
rock and glass created during volcanic eruptions.
These fragments are so small, and heated to such a
temperature that they can be carried in the air for
many kilometers.
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Volcanic BombsVolcanic bombs are chunks of lava blasted into the
air which solidify before they reach the ground. Some
bombs can be extremely large, measuring 5-6 meters
in diameter and landing more than 500 meters from
the volcanic vent.
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Negative Effects of Volcanoes• Eruptions occurring close to human settlements may
spill and destroy lives and property. People often
have to be evacuated.
• Landscapes and natural sceneries can be
destroyed.
• Ash and mud can mix with rain and melting snow,
forming lahars. Lahars are mudflows flowing at very
fast pace.
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The negative effects of volcanoes eruption J
Positive Effects of Volcanoes• Different types of erupting volcanoes provide
extraordinary scenery, so beautiful and natural that
they attract tourists to the area, bringing in some
economic value.
• Places close to volcanic activities tend to have
higher potential for geothermal energy, which can
be an advantage to the towns and cities.
• Some ash and lava breakdown become soils that
are rich in nutrients, and become good areas for
crop planting activities.
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The positive effects of volcanoes eruption E
Definition of Explanation Text
A. Definition
Explanation is a text which tells processes relating to forming of
natural, social, scientific and cultural phenomena. Explanation
text is to say ‘why’ and ‘how’ of the forming of the phenomena.
It is often found in science, geography and history text books.
B. Purpose
purpose of the text is to explain the processes that occur in the
formation or activity associated with natural phenomena, social,
scientific, cultural, and others aimed at explaining.
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C. Generic Structure
General statement; stating the phenomenon issues which are
to be explained.
Sequenced explanation; stating a series of steps which
explain the phenomena.
D. Language Features
1.Focusing generic participant; daylight.
2.Using chronological connection; then, so, but.
3.Using pasive voice; you would be forgiven.
4.Using present tense; the earth is actually closer to the sun.
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Thanks for your attention….
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