OBJECTIVES:

• Exploring the many hazards associated with volcanoes.
• Discussing the hazards associated with volcanoes.

VOCABULARY:

• ash fall
• earthquake
• erupt
• hazard
• lava flow
• mudslide
• volcanic bombs

MATERIALS:

• Leaving the Fiery Slopes of Mount Etna by J. Blueford

Students speculate about the effects of volcanic hazards.

An eruption in Hawaii.

BACKGROUND:

Volcanoes are a surface feature of molten rock below the surface of the Earth. When pressure builds up, eruptions occur. Gas and rock shoot up through the opening; lava flows downward along the sides of the mountain. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods (if melting snow). Volcanic eruptions have been known to knock down entire forests in one large, burst of hot air. An erupting volcano can trigger tsunamis, flashfloods, earthquakes, mudflows and rock falls.

Many hazards are associated with volcanic eruptions.  When lava (melted rock) erupts, a thick, hot, viscous liquid flows downhill. It is very hot, so it burns or melts almost everything that is in its path. Gases, such as CO₂ (carbon dioxide), CO (carbon monoxide) and SO₂ (sulfur dioxide) are also emitted by volcanoes. They may fill valleys with a thick blanket of toxic gas, which may kill much of the life in the area.

Landslides are downhill movement of loose material on the side of a volcano. Landslides on volcanoes result when unstable rocks are shaken loose during eruptions, or when ash mixes with water and snow, making a thick slurry that flows down the sides of the volcano. Earthquakes occur as magma moves upward inside the volcano, and as energy is explosively released during an eruption. The earthquakes associated with volcanoes are usually relatively small; they generally cause little damage by themselves.

Some volcanoes are explosive and kill people and other animal life with little warning. Three  examples are Mt. Pinatubo in the Philippines, Mount St. Helens in western Washington, and Nevado del Ruiz in Columbia. Some volcanoes, however, like Kilauea in Hawaii or Mount Etna in Italy, usually erupt quietly, spewing out lava flows.  But even quiet ones sometimes explore when least expected, as the animated storybook illustrates.

PROCEDURE:

1. Using the list of volcanic hazards below, ask the students to predict the effect each hazard would have on a person or a home. The hazards and some of their destructive capabilities are listed below.
      
   1. HOT LAVA - temperatures can melt steel, burn wood structures
   2. VIOLENT ERUPTIONS - produce ash, which may bury surrounding areas up to many miles away.
   3. VIOLENT ERUPTIONS - produce ash and mudslides, which destroy life and property around the volcano.
   4. GASES - can cause suffocation
   5. EARTHQUAKES - may trigger landslides
   6. LANDSLIDES - bury and destroy homes, carry people away.
        
2. In most cases the students should answer that the people or homes will be severely damaged or destroyed if they are too close to the volcano.
    
3. Read Leaving the Fiery Slopes of Mount Etna by J.R. Blueford and discuss the different hazards that faced the Pagano Family.  Also discuss the long term effects of such natural disastrous and how it can change the life of people.

(*NOTE--FOR THE HAZARDS- LAB, STUDENTS NEED TO BRING IN THEIR MODELS OF MT. LASSEN FROM THE VOLCANOES UNIT BACK INTO THE CLASSROOM).

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