NSSS3.2

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=3.2 Volcanic Activity=

Vocabulary

 * Magma Chamber**: A pocket in which magma collects.
 * Pipe**: A long tube in the ground that connects the magma chamber to Earth's surface.
 * Lava Flow**: The area covered by lava as it pours out of a vent.
 * Crater**: A bowl- shaped area that may form at the top of a volcano around the volcano's central vent.
 * Silica**: A material that is formed from the elements oxygen and silicon.
 * Pahoehoe**: Fast-moving, hot lava.
 * Aa**: Lava that is cooler and slower-moving.
 * Pyroclastic Flow**: It occurs when an explosive eruption hurls out ash, cinders, and bombs as well as gases.
 * Active**: Volcano is one that is erupting or has shown signs that it may erupt in the future.
 * Dormant**: Volcano that is like a sleeping bear.
 * Extinct**: Volcano that is unlikely to erupt again.
 * Hot Spring**: A hot spirng forms when groundwater heated by a nearby body of magma rises to the surface and collects in a natural pool.
 * Geothermal** **Energy**: In volcanic areas, heated by magma can provide a clean energy source called geothermal energy.

How Magma reaches

 * Magma rises
 * Dissolved gases in magma are under immense pressure
 * When a volcano erupts, it means that the gases have found a weak spot and have been released

Inside a Volcano

 * Inside a volcano, there is a magma chamber
 * There is a pipe which connects the chamber to the surface
 * When a volcano erupts, you are seeing molten rock and gas leaving a vent

Characteristics of Magma

 * Important Factors in an eruption
 * The amount of gas in the magma
 * How think or thin the magma is
 * Temperature of the magma
 * The hotter the magma, the more fluid it is
 * The silica content in the magma
 * The more silica in magma, the thicker it gets
 * Minerals that are formed by lava
 * Obsidian
 * formed when lava cools rapidly
 * Pumice
 * forms when gas bubbles are trapped inside the cooling magma

Types of Volcanic Eruptions

 * Quiet Eruptions
 * When magma flows out easy, the volcanic eruption is quiet
 * Hawaii and Iceland were results of quiet eruptions
 * 2 different types of lava arre created through quiet eruptions
 * Pahoehoe
 * Fast moving hot lava
 * Land created by pahoehoe is like a potpourri of wrinkles,billows,and coils
 * Aa
 * Slower and cooler lava
 * When hardened, it has a rough surface containing jagged chunks of lava
 * Explosive Eruptions
 * When the magma is thick and sticky, the results are an explosive eruption
 * The thick magma clogs up the hole and trapped gases can't escape until they explode, which result in the magma being forced out.

Stages of a Volcano

 * A volcano may lay be active or dormant from a decade to 10,000,000 years
 * An extinct volcano is one which can never erupt again

Other Types Of Volcanic Activity

 * Two types of volcanic activity
 * Hot Spring
 * formed when magma heats groundwater and collects in a pool
 * Geyser
 * formed when hot water and steam are trapped and then comes up as a mixture
 * In Reykjavik, Iceland, people rely on geothermal energy for warmth

Monitoring Volcanoes
Geologists have more luck predicting volcanic eruptions than earthquakes
 * Movement of magma into the magma chamber and through the pipe of the volcano trigger small earthquakes which help geologists find out if the volcano will erupt

Volcano Hazards

 * Volcanic ash can bury towns, people, and damage crops