Volcanoes: Nature’s Awesome Power

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Volcanoes: Nature’s Awesome Power By Maryann Dobeck

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Volcanoes: Nature’s Awesome Power. By Maryann Dobeck. Introduction. Centuries ago, native people of Hawaii witnessed volcanic eruptions. A Hawaiian myth is that a goddess of volcanoes made mountains blow their tops. - PowerPoint PPT Presentation

Transcript of Volcanoes: Nature’s Awesome Power

Page 1: Volcanoes: Nature’s Awesome Power

Volcanoes: Nature’s Awesome Power

By Maryann Dobeck

Page 2: Volcanoes: Nature’s Awesome Power

Introduction• Centuries ago, native people of

Hawaii witnessed volcanic eruptions. • A Hawaiian myth is that a

goddess of volcanoes made mountains blow their tops.• Scientists know that forces of

nature are the cause of volcanic eruptions.

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CH.1: The inside story of volcanoes p• Earth is made of four layers,

outer layer is the crust.• Geologist’s believe the crust and

upper mantle are made of 10 huge plates and 6 smaller plates.• The world’s erupting volcanoes

occur along edges or boundaries, of earth’s plates

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• Volcanoes are mountains that are built from eruptions of volcanic materials onto earth’s surface.• When pressure on the magma

subsides, the eruption stops.• Three kinds of materials may

erupt from a volcano: lava, tephra (rock fragments), and gases.

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• The pressure of the gas in the magma causes the eruption.• A volcano erupts, it can spew

out anything from fine particles of dust to huge block of rock as big as a house.• If magma contains a lot of gas, it

will burst out violently with rock fragments called pyroclastic materials.

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Volcanoes on ocean floor/Volcanoes at hot spot• Tectonic plates on the ocean

floor are thinner than plates on land.• In 1963, a volcano formed a new

island called Surtsey.• The largest volcanoes are above

hot spots, areas of superhot rock deep in earth’s.

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CH.2: Types of volcanoes• Their are three common types of

volcanoes: stratovolcano, cinder cone volcano, and shield volcano.• Geologist classify volcanoes

based on their size, shape, and formation.• Stratovolcanoes usually have

steep sides and a broad base.

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Cinder cones• As lava explodes from the

central vent it breaks into small pieces that fall as cinders around the opening.• Paricutin volcano in Mexico is

one the most famous cinder cone volcanoes.• This volcano usually starts out

small but they quickly build up into a large volcano.

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Shield volcanoes• Shield volcanoes are flat and

wide.• Most of the Hawaiian Island are

shield volcanoes.• Mauna Loa is the worlds largest

Volcano.

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CH.3• When volcanoes erupt geologists

call the most explosive volcanic eruption a Paleean eruption .• Scientists call the least violent

kind of eruption a Hawaiian eruption.• Lava streams out of several vents

and forms a shield volcano.

• 1 of the worlds most DANGEROUS volcano.

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CH.4: Famous volcanoes & mountains• When mount Vesuvius erupted,

ash and lava buried the towns of Pompeii, Herculaneum ,and Stabiae, Krakatoa.• No one lived on Krakatoa, so no

one died.

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Mount ST. Helens• The volcano rumbled with

earthquakes.

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Mount Pinatubo• Mount Pinatubo erupted in a

powerful blast 10 times larger than the eruption of MT. St. Helens.