volcanoes

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Volcanoes Volcanoes are openings in the Earth’s surface. When they are active they can let ash, gas and hot magma escape in sometimes violent and spectacular eruptions. The word volcano originally comes from the name of the Roman god of fire, Vulcan. Volcanoes are usually located where tectonic plates meet. This is especially true for the Pacific Ring of Fire, an area around the Pacific Ocean where over 75% of the volcanoes on Earth are found. While most volcanoes form near tectonic boundaries, they can also form in areas that contain abnormally hot rock inside the Earth. Known as mantle plumes, these hotspots are found at a number of locations around the globe with the most notable being in Hawaii. Hot liquid rock under the Earth’s surface is known as magma, it is called lava after it comes out of a volcano. Some famous volcanic eruptions of modern times include Mount Krakatoa in 1883, Novarupta in 1912, Mount St Helens in 1980 and Mt Pinatubo in 1991. While we certainly have some big volcanoes here on Earth, the biggest known volcano in our solar system is actually on Mars. Its name is Olympus Mons and it measures a whooping 600km (373 miles) wide and 21km (13 miles) high. The object with the most volcanic activity in our solar system is Io, one of Jupiter’s moons. Covered in volcanoes, its surface is constantly changing to the large amount of volcanic activity. Most people think of volcanoes as large cone shaped mountains but that is just one type, others feature wide plateaus, fissure vents (cracks were lava emerges) and bulging dome shapes. There are also volcanoes found on the ocean floor and even under icecaps, such as those found in Iceland. Volcanoes can be active (regular activity), dormant (recent historical activity but now quiet) or extinct (no activity in historical times and unlikely to erupt again). While these terms are useful, scientists are more likely to describe volcanoes by characteristics such a how they formed, how they erupt and what their shape is. Common volcanic gases include water vapor, carbon dioxide, sulfur dioxide, hydrogen chloride, hydrogen fluoride and hydrogen sulfide. Volcanic eruptions can send ash high into the air, over 30km (17 miles) above the Earth’s surface. Large volcanic eruptions can reflect radiation from the Sun and drop average temperatures on Earth by around half a degree. There have been several examples of this over the last century. Pumice is a unique volcanic rock (igneous) that can float in water. It can also be used as an abrasive and is sometimes used in beauty salons for removing dry skin. What is a Volcano? A volcano is a landform (usually a mountain) where molten rock erupts through the surface of the planet. In simple terms a volcano is a mountain that opens downward to a pool of molten rock (magma) below the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt. Did you know? The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology. As pressure in the molten rock builds up it needs to escape somewhere. So it forces its way up “fissures” which are narrow cracks in the earths crust. Once the magma erupts through the earth’s surface it’s called lava. volcano hat is the difference between lava and Magma? Magma is liquid rock inside a volcano. Lava is liquid rock (magma) that flows out of a volcano. Fresh lava ranges from 1,300° to 2,200° F (700° to 1,200° C) in temperature and glows red hot to white hot as it flows. volcano How many volcanoes are there in the world? There are around 1,510 active volcanoes in the world. We currently know of 80 or more which are under the oceans. volcano What are the three layers the Earth is made of? Crust The crust is the outer layer of Earth. It is about 18 miles thick. It is the part we live on. Mantle The second layer is called the mantle. It is about 1,800 miles thick. Core The inner layer is called the core. volcano What causes volcanoes to erupt? The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. Between the Earth's crust and the mantle is a substance called magma which is made of rock and gases. When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed up between two plates. Did you know? Volcanoes are like giant safety valves that release the pressure that builds up inside the Earth. volcano When magma erupts, what is it called? When magma erupts through the earth's surface it is called lava volcano What is the Ring of Fire? Over half of the world’s volcanoes arise in a belt around the Pacific Ocean called the Ring of Fire.

section through the Earth underline the important words
earthquake/subduction underline the important words	gif of earthquake tremors underline the important words
map of pangaea and the countries it became underline the important words
plate tectonics/plate formation underline the important words	plate tectonics/collision forming moutains underline the important words	plate tectonics/pulling apart underline the important words
plate tectonics/Pacific rim underline the important words	gif of earthquake sitings underline the important words
tectonic plates/subduction/volcano formation underline the important words	lava flowing from secondary vents underline the important words	gif of underwater volcanic vent forming underline the important words
cone volcanic eruption underline the important words	big volcanic eruption underline the important words
normal fault/earthquake underline the important words	normal fault/earthquake/sliding underline the important words	sliding fault underline the important words
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eruption of Pompei underline the important words
divergent forces underline the important words	mid oceanic ridge underline the important words	divergent underline the important words
subduction zone underline the important words
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