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Transcript of Volcanoes
The Earth is amazing, it is constantly moving and changing, the Earth's power is astonishing. The Earth is always moving and we don't even notice!
Ring of Fire
The "Ring of Fire" (map) is an arc stretching from New Zealand, along the eastern edge of Asia, north across the Aleutian Islands of Alaska, and south along the coast of North and South America. The Ring of Fire is composed over 75% of the world's active and dormant volcanoes
The Layers of the Earth
The Earth is made up of four basic layers. There is the crust, the mantle, the outer core and the inner core.
Hawaiian Volcanic Activity
The tectonic plates are on the Earth's crust or surface. The tectonic plates are like giant jig saw pieces. When they move they cause earthquakes, tsunamis and volcanic activity, these can have catastrophic endings.
Inside a volcano
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.
Benefits of Volcanoes
Highly volcanic areas have some of the most fertile farmland in the world.
Volcanic eruptions bring nutrients such as potassium and phosphorus to the Earth’s soil.
The weathering of volcanic rocks also releases nutrients.
Yellow Stone Supervolcano
1. The Yellowstone Super Volcano could erupt with 10,000 times the force of the explosion at Mount. St. Helens in 1980.
Yellowstone National Park in Wyoming sits on the site of an ancient supervolcano.
It erupted around 2 million years ago, 1.3 million years ago, and 640,000 years ago.
If it follows the same pattern, another eruption is due any time now.
Main Features of a Volcano
Here are the main features of a volcano there is the magma chamber which holds all of the lave or magma when the volcano is erupting the lava spurts through the main vent which goes through the middle of the volcano and the secondary vent which is on to the side of the volcano which can forms a crater. The lava oozes down the side of the volcano this is called the lava flow. There also is something called volcanic bomb, that is a mass of molten rock that is larger than 65 mm in width. It can be thrown at incredible distances away from the volcanic vent and is categorised into bread crust bombs, core bombs, cow pie bombs and ribbon bombs.
So we have learned that volcanoes are formed by the tectonic plates, they bring destruction such as Pompeii and they also bring benefits, they can be on the ground and in the water and on other planets, 75% of volcanic eruptions are in the Ring of Fire, there are different parts of the volcano, they can be different shapes and sizes and that volcanoes are one of the most amazing things in the universe that man-kind has seen.
Volcanoes aren't just on the ground on Earth they are also in the ocean and on different planet. Did you know that the biggest volcano on Earth is called Tamu Massif. The top of Tamu Massif lies about 1,981 m below the ocean surface, while much of its base is believed to be in waters that are almost 6.4 km deep.
Structure of the Earth
Tectonic Plates and Ring of Fire
Mt. St Helens
During the past 400 years, nearly a quarter of a million people have been killed as a direct result of volcanic eruptions.
Indirect after effects such as famine, climate change, and disease most likely have tripled that number.
The most dangerous volcano today is Popocatépetl, nicknamed El Popo, which is just 53.11 km from Mexico City.
El Popo is still active, sending thousands of tons of gas and ash into the air each year.
In 1963, an undersea volcano created the newest land mass on Earth, Surtsey Island, which lies off the southwest coast of Iceland.
Today Surtsey is about 1 609 sq. metre and is named after Surt, a fire giant from Norse mythology.
Pele is the Hawaiian goddess of fire and volcanoes and was thought to live in the crater of the Kilauea volcano on Hawaii.
She is said to have a terrible temper and will throw lava at anyone who angers her.
“Lava” derives from the Latin lavara, meaning “to wash,” and is magma that has erupted at the surface.
Lava can flow up to speeds of 99.78 km per hour.
The material ejected from a volcano is called “pyroclastic flow” from the Greek pyr (fire) and klastos (broken).
It includes small fragments of rock, frothy pumice, and large boulders.
Pyroclastic flow can reach temperatures of 100° c and can rocket down the side of a mountain at 249.9 km.p.h.
Volcanologists use a special electric thermometer called a “thermocouple” to take a volcano’s temperature. Lava is so hot that a glass thermometer would melt.
Volcanologists measure the size of an eruption with the Volcanic Explosivity Index (VEI), with 0 being the weakest and 8 the strongest. Eight is usually reserved for super eruptions, popularly called “supervolcanoes.
Magma is Latin for “dregs of ointment,” which derives from the Proto Indo-European mag meaning “kneading.”
In some volcanic areas such as Iceland, heat energy from magma can be used to warm water and run power plants.
This type of energy is called geothermal (earth heat) energy.
Japan has 10% of the world’s active volcanoes.In Japan, “baths” in warm volcanic sand are believed to cure many illnesses.
The three main types of volcano shapes are
Stratovolcanoes, also called composite volcanoes, are the most common type of volcanoes and often have symmetrical steep slopes.
About 20% of all volcanoes are under water.
There are no active volcanoes in Australia because it sits in the middle of a tectonic plate.
How volcanoes form
(When two tectonic plates smash against
(When two plates drift apart)
IN A HOT SPOT
(a weak spot in one of Earth’s plates)