Presentation on theme: "Chapter 9 Page 250. Create a labeled drawing that illustrates what happens when a volcano erupts."— Presentation transcript:
Chapter 9 Page 250
Create a labeled drawing that illustrates what happens when a volcano erupts.
Mt. Etna, one of Italy's (and the world's) most active volcanoesEtna May 10, 2008
Volcanoes- are areas in the earths surface where magma and volcanic gases exit Magma- molten rock or liquid rock that is extremely hot
They form fertile farmland Create mountains and Islands
Most common type of eruption Produce calm flowing lava (in large amounts) Common on land and ocean floor Thin runny oozes from vents What types of lava? _______________
Thick and sticky magma will not flow out of volcano. Instead, it plugs the vent like a cork in soda bottle. Dissolved gases cannot escape, build up pressure until they explode. Clouds of hot debris and gases shoot out from the volcano, often at supersonic speeds. Molten rock is blown into millions of pieces that harden in the air.
TERMS TO KNOW Lava is magma once it exits a vent The vent is any opening on the surface were volcanic materials escape Magma Chamber – a body of molten rock under the earth surface Vent Lava
Water stays dissolved in magma only when it is extremely hot and under pressure As magma moves to the surface it cools and pressure decreases water and CO2 turn to gas state This causes lava to become explosive Pumice –Lava filled with gas and can float on water
High levels of Silica also cause explosive eruptions Silica makes magma thick Lava flows slower The lava gets stuck in vents Gases are trapped till pressure builds
What are the two types of eruptions and describe them. Try to Illustrate each
Lava Liquid magma (or molten rocks) Normal found in non explosive eruptions Four Main types Aa Pahoehoe Pillow lava Blocky lava Pyroclastic Material Lava is blasted into the air and has time to cool and harden Normally present in explosive eruption Four Main types Volcanic Bombs Lapilli Volcanic Ash Volcanic Blocks
High Viscosity Low Viscosity Moves Quickly Moves Slow
Lapilli (lah PIL IE) Tiny pebble like pieces of lava that harden before hitting the ground Volcanic Bombs Large blobs of magma that form in the air Volcanic Ash Forms when gases in magma expand rapidly Volcanic Blocks Largest pieces of volcanic material. Solid rock erupting
Very dangerous Enormous amounts of hot ash, dust and gases are ejected form volcanoes Temp can be more than 700°C See page 255 video
Put Your Name on The Front Three types of volcanic eruptions Describe each type (list things seen in each) 3-4 facts Draw a image or print one from the internet for HW Label important parts on each image Ex (lava, debris, gas, rocks)
Give me an example of two solutions label one high viscosity and the other low What are two the main groups of things that erupt from a volcano
1. Aa 2. Pahoehoe 3. Pillow lava 4. Blocky lava 5. Volcanic Bombs 6. Lapilli 7. Volcanic Ash 8. Volcanic Blocks Front Back AA (Name of object) Two important fact describing If it is lava or pyroclastic material
List the type of eruptions starting with most dangerous ending with least dangerous? Tell why you consider one most dangerous? Because the book or notes said so is not an answer.