Volcanoes

By Natassia Katsavos

*Volcanoes*

A volcano is an opening in Earth’s crust through which molten lava, ash and gases erupt. In many cases, lava and ash for a mountain around the opening. It used to be thought that volcanoes leaked molten rock and gases directly from Earth’s core. That is not the case. As hot, solid rock rises in the mantle, the pressure drops and a small part of the rock begins to melt. This liquefied rock, called magma, is less dense than solid rock. It squeezes out from the solid like water from a sponge. The rising magma creates wide channels in the crust as it forces its way to the surface. When it brake through the surface, the pressure drops. Gases dissolved in the magma force it to erupt through the opening as lava.

*The Ring Of Fire*Most volcanoes occur near cracks between the giant tectonic plates that make up the Earths surface. Around the Pacific there is a ring of explosive volcanoes called ‘The Ring Of Fire’. There are about 60 major volcanic eruptions a year, including two or three huge violent eruptions.The ring of fire is placed in the Pacific Ocean,Asia,North America,South Africa& New Zealand. The Ring of Fire is surrounded by the Pacific Plate, which is surrounded by the Pacific Ocean.  It contains more than half of the world’s volcanoes.  Some of the world’s famous volcanoes are in this fantastic ring in the ocean.  The existence is explained by plate tectonics.  The Ring of Fire is on one of the plates of the earth’s crust.  Newly-formed magma rises to the air of the earth’s surface and erupts, forming chains of these violent volcanoes, like the Ring of Fire. The Ring of Fire is very big.  It stretches from New Zealand to Alaska and eastern Asia to North and South America.  The Ring of Fire also produces heavy seismic activity.  Frequent earthquakes are also very common in the Ring of Fire.

*Structure Of A Volcano*

These pictures are diagrams of volcanoes.

* Where Volcanoes Are*

This is a map of where volcanoes erupt.

*Rocks Found In Volcanoes*

The various types of rocks found in volcanoes include: Subvolnic rocks, Plutonic rocks, Pyroclastic rocks, Igneous rocks, Ryolite rocks, Basaltic rocks, Crystals & many more. When all of these rocks fly out of the volcano many of them would of melted especially the crystals.

*Facts About Volcanoes*

The biggest volcanic eruptions are powered by a combination of steam and carbon dioxide gas. They stay dissolved in the magma which is inside the volcano because of the extreme pressure. However, as the plug of the magma breaks, the pressure is then released which creates an explosion big enough to send chunks of rick the size of houses many thousands of meters up into the air.

*Types Of Volcanoes*

There are many different types of volcanoes such as: Subglacial volcanoes, Shield volcanoes, Cinder volcanoes, Stratovolcanoes (Also called Composite volcanoes), Super volcanoes Submarine volcanoes, Cone volcanoes, Spatter volcanoes, Complex volcanoes ( Also called Compound volcanoes), Fissure volcanoes, Dome volcanoes, Conical volcanoes and Caldera volcanoes.

*What Are Volcanoes *

Volcanoes are mountains but unlike most mountains in the world formed from folding continental plates uplift and erosion volcanoes are created when materials from inside the earths escapes to the surface. As you probably know the ground you're standing on is the earths crust .It varies in depth between 10km under the oceans and 30km beneath the continental plates. Beneath the crust is a vast region called the earths mantle. The mantle is made up of molten rock called magma. At the boundaries between continental plates, volcanic vents can open up, where magma and gasses from inside the earth can escape when its still underground, the molten rock is called magma. Although most of the earths mantle is solid it can create pockets of liquid which escape from underneath through weakness in the earths crust. After it escapes to the surface, its called lava.

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*Effects & Hazards*

The sudden violence of volcanic eruptions causes catastrophe and devastation. Various eruptions of volcanoes in the past such as Mount Pelee, Tambora, Krakatau and Pinatubo have demonstrated the devastating impact of volcanic activity on nearby landscapes and communities. Many people got killed and a large amount of people had to abandon their homes. Even the Earths climate was changed for a while as a result of an eruption for a period of time! These effects of volcanic eruptions are mostly the result of certain hazards. Volcanoes provide different hazards during an eruption. Each hazard poses risks on different areas, the most threatening hazards include:Pyroclastic Flows, Nuees Ardentes, Volcanic Ashes, Lahars, Debris Avalanches, landslides, tsunamis, Blast, Lava, Types of Lava Flows and Gas.

*How There Formed*

Most volcanoes occur where two plates meet. When two plates move apart causing a gap, hot molten rock - called lava - rises up between them. This type of volcano occurs on the ocean floor and is mostly invisible. If the amount of magma is large enough, it rises above the surface of the ocean and an island is created. If two plates collide and one plate is forced beneath the other plate, the friction makes the first melt and magma rises up. Only a few volcanoes on earth are formed like this, but their eruptions are the most violent and dangerous ones. Sometimes volcanoes also form in the middle of the plates which are called hotspots. These are places that are connected by channels to the hot mantle of the earth.

*Picture Page!*

*Bibliography*

*Internet*

Kids cyber

Google

Natural Disasters.com

& more!

*Books*

The kingfisher science encyclopedia

The five mile press book of knowledge.

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