When Volcanoes Erupt PG. 107

Volcano a break/hole on the crust of Earth that emits lava, ash, and gases. (usually forms a mountain)

What’s inside a volcano? Crater The central funnel shaped vent at the top of a volcano Vent—an opening at the surface of the Earth through which volcanic material passes Magma Chamber—the body of molten rock that feeds a volcano Magma Chamber

What are non- explosive eruptions? Volcanoes that erupt only lava and gas The most common type of eruption

What erupts from a volcano? 1. Lava-- 4 types Pahoehoe Flows slowly, smooth glassy surface A’a—pours out quickly, brittle jagged surface

Pillow lava—lava that erupts under water Blocky lava—sharp edged chunks of stiff lava

What are explosive eruptions? Clouds of hot rock, ash and gas rapidly shoot out from the volcano Millions of tons blast out in a few seconds

2. Pyroclastic material 4 types of material Bombs—large blobs of magma that harden when they fly through the air Blocks—largest pieces of solid rock blown away from the volcano

4. Volcanic ash– magma explodes into tiny glass like slivers 3. Lapilli—little stones of magma that harden before they hit the ground

What are pyroclastic flows? Enormous amounts of hot ash, dust and gas are ejected from a volcano Races downhill at more than 200 km / hr Temperatures can exceed 700 degrees C

What are the effects of volcanic eruptions? Climate can be changed as ash and gas spread throughout the atmosphere Eruptions can affect the whole Earth with lower temperatures

Other effects… Pyroclastic materials (ash and rock) can travel at high speeds and can be deadly Lava can be very destructive—it’s very hard to stop

Mt. Vesuvius and Pompeii

Mt. Vesuvius and Pompeii

3 types What are other types of Volcanic Landforms? 1. Lava Lakes- large amounts of molten lava contained in a depression A

2. Calderas A semicircular depression that forms when the magma chamber partly empties and causes the ground above to sink Many times larger than a crater

3. Lava Plateaus A wide flat area caused by repeated nonexplosive eruptions of lava that spread over a large area