Plate Tectonic - Hazards (1)
Post Lab 

  • Investigating Mt. Shasta, California.
  • Discussing the different types of hazards.
  • ash
  • landslide
  • lava

Students are exposed to different volcanic hazards.

Mt. Shasta


Mt. Shasta is in northern California, part of the Cascade Range. Studies by geologists show that Mount Shasta has erupted 10 or 11 times during the last 3,400 years and at least 3 times in the last 750 years. Mount Shasta does not erupt at regular intervals, but its history suggests that it erupts at an average rate of once every 600 year during the last 4,500 years. Future eruptions could develop from vents at or near the present summit. In the picture above, a second cone, called Shastina can also erupt.

The type of eruption would most likely be explosive. Explosive eruptions can produce volcanic ash, pyroclastic flows, and lateral blasts. Non-explosive eruptions, can also develop after the initial eruption and form lava flows and domes. Both types of eruptions can cause mudflows down local drainage, and both types often are accompanied by gas emissions.

  1. Discuss the information on Mt. Shasta with the class. Show the students the slides of dangers associated with a volcano (see below). If you project the picture large enough, have students "walk" amongst the rubble.
  2. Show the slides that illustrate the following terms. At this point, you are just exposing the students to the terms. They should not attempt to memorize them.

    Volcanic ash = small particles of the magma that are blown out of the volcano. They are carried away by the wind, along with volcanic gases
    Volcanic gases = gases emitted by a volcano either alone or along with ash or lava. Volcanic gases consist chiefly of water vapor, carbon dioxide, carbon monoxide, and various compounds of sulfur, chlorine, and other elements.

    Pyroclastic flows = streams of hot ash and rock fragments that are mixed with hot air and other gases. Together these form a fluid which rapidly flows down the side of a volcano.

    Lava flow = a "river" of lava that moves downhill and can crush, burn, and bury structures

    Mud flow = a mass of water-saturated rock debris that moves downslope as a fluid

    Landslide = a downhill flow of rock debris on the side of a volcano

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