When Volcanoes Erupt PG. 115

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

3. Lapilli—little stones of magma that harden before they hit the ground

4. Volcanic ash– magma explodes into tiny glass like slivers

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

Mt. Vesuvius and Pompeii

What are other types of Volcanic Landforms? 3 types

1. Craters

The central funnel shaped vent at the top of a volcanoA

2. Calderas

Many times larger than a crater

A semicircular depression that forms when the magma chamber partly empties and causes the ground above to sink

3. Lava Plateaus

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