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Volcanoes

Volcanoes. Volcano Eruption. A volcano – is an opening in Earth’s crust through which molten rock, rock fragments, and hot gases erupt. . Magma. Also contains gases, which expand as the magma rises. Composed of silicon and oxygen compound.

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Volcanoes

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  1. Volcanoes

  2. Volcano Eruption • A volcano – is an opening in Earth’s crust through which molten rock, rock fragments, and hot gases erupt.

  3. Magma • Also contains gases, which expand as the magma rises • Composed of silicon and oxygen compound • Pressure builds up until the gases blacks out in a violent explosion

  4. Magma • Magma rises toward Earth’s surface if it is less dense than the surrounding rock. • Magma chambers – holds magma until it can not hold any more and forces the magma out through an eruption.

  5. Lava • Lava – is magma that has reached Earth’s surface

  6. Rock Fragments • Ash – tiny rock fragments. Size of dust to rice grain. Can be carried long distances by wind (even all the way around Earth) • Block – Can be the size of houses are solid pieces of rock. Fall quickly after eruption • Cinders – bigger than ash, contain holes and tunnels left by escaping gases

  7. Volcano Shapes and Sizes • Shapes of Volcanoes depend on Magma Feeding 1.) Most erupt from openings in bowl-shaped pits called craters. 2.) Some erupt from long cracks in the ground

  8. Shield Volcano • Shaped like a broad, flat dome. • Low silica (flows easily) • Largest Volcano on Earth and one of the most active! • Name: Mauna Loa • Location:Hawaii • Height:10.5 milesmost is underwater!

  9. Cinder Cone • A steep, cone-shaped hill formed by the eruption of cinders and other rock fragments that pile up around a single crater. • One of the most famous volcanos • Name:Parícutin • Location:Mexico • Height:1.73miles

  10. Composite Volcano • A cone-shaped volcano built up of layers of lava and layers of rock fragments. • High silica (flows slower and is pasty) • Deadliest and most destructive volcanic event in the history of the US • Name:Mount St. Helens • Location:Washington, US • Height:1.58 miles

  11. Monitoring Volcanoes • Scientist monitor • Magma movement • Temperatures at openings, springs, and lakes on volcanoes • Amount and type of gases given off • Rising temperatures • Changes in volcanic gases

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