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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.

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Presentation on theme: "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."— Presentation transcript:

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3 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.

4 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.

5 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.

6 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.

7 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.

8 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.

9 Mt. St Helen In 1980 on the 18 th 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.

10 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’.

11 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.

12 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.

13 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.


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