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Volcanoes! By Angie Johnson

What is a volcano? A volcano can be defined as “An opening in the earth's crust through which molten lava, ash, and gases are ejected”. We don’t need to look any further than our own backyard to find active volcanoes!. Volcanoes! By Angie Johnson. Did you know?.

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Volcanoes! By Angie Johnson

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  1. What is a volcano? A volcano can be defined as “An opening in the earth's crust through which molten lava, ash, and gases are ejected”. We don’t need to look any further than our own backyard to find active volcanoes! Volcanoes!By Angie Johnson

  2. Did you know? • A volcanic eruption can cause lava flows, hot ash flows, mudslides, avalanches, tsunamis, earthquakes, and rock falls. Volcano eruptions have been known to knock down entire forests. This happened when Mount St. Helens erupted on May 18, 1980 in Washington state. • More than 80 percent of the earth's surface was formed by volcanoes. Gaseous emissions from volcanoes formed the earth's atmosphere. • There are more than 500 active volcanoes in the world!

  3. A Volcano Video

  4. Parts of a Volcano vent Ash cloud side vent lava conduit crust Magma chamber

  5. Many currently active volcanoes are located in Oregon, Washington, and California. One of the most powerful eruptions occurred on May 18, 1980 when a powerful 5.1 earthquake triggered a devastating eruption on Mount St. Helens. Can you find it on the map?

  6. Mount St. Helens May 17, 1980 the day before…

  7. Mount St. HelensMay 18, 1980 8:32 a.m.

  8. The eruption begins…

  9. A witness to geologic history

  10. Within 3 minutes, the lateral blast, traveling at more than 300 miles per hour, blew down and scorched 230 square miles of forest.

  11. Within 15 minutes, a vertical plume of volcanic ash rose over 80,000 feet.

  12. The blast took 1,300 feet off the top of the mountain!

  13. Ash from the eruption was seen thousands of miles from the mountain The volcanic ash cloud drifted east across the United States in 3 days and encircled Earth in 15 days.

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