Volcanoes are Hot Stuff By Shana Huffaker And Doreen Snyder Modified by Mr. Kennedy

What is a Volcano? Volcano- Areas of earth’s surface through which magma and volcanic gases pass Volcano comes from the Roman word Vulcan, which means “fire” Magma rises because it is less dense than the solid rock around it.

What are the parts of a Volcano? VENT- the vent is the opening from which lava flows. Dust, ash, and rock particles can also be thrown out of the vent!

A lava flow is the area covered by lava as it pours out of a vent A crater is a bowl-shaped area that may form at the top of a volcano around the central vent

Craters, Calderas, and Lava Plateau From explosions of material out of the vent and the collapse of material back into vent Caldera Much larger depression that forms when magma chamber empties and its roof collapses Lava Plateau Forms when lava erupts from long cracks, or fissures, and spreads out evenly (thousands of km)

How are volcanoes formed?

Deep in the earth it is very hot. It is so hot that rocks melt Deep in the earth it is very hot. It is so hot that rocks melt. The melted rock is called magma. The magma is lighter than the rocks around it so it rises. Sometimes it finds a crack or hole in the earth’s crust and bursts through. This is how a volcano begins.

Why do volcanoes erupt?

Pressure builds deep in the earth where the magma is Pressure builds deep in the earth where the magma is. Suddenly the gases escape and violently explode. It is kind of like toothpaste squirting out of a tube when you give it a hard squeeze.

What are the different kinds of volcanoes?

Volcanoes do not all look alike Volcanoes do not all look alike. Their shape is based on what type of materials they erupt. There are three main kinds, or shapes, of volcanoes.

3. Volcanic cone- is the pile of lava, dust, ashes, and rock around the vent. It can be found in different shapes!

Types of Volcanoes Shield volcano Cinder cone volcano Composite volcano

Shield Volcanoes

Volcanoes that build up from many slow, steady, flows of hot lava, are called shield volcanoes. This kind of volcano is low and broad with gently sloping sides. They look like a warriors shield.

Shield Volcano Is wide and somewhat flat. It forms from a quiet eruption. Lava flows out quietly and for great distances.

Cinder Cone Volcanoes

Cinder cone volcanoes form when solid rock and ash shoot up into the air and fall back around the volcano opening. The cinder cone volcano has steeply sloped sides.

Cinder Cone Volcano Has tall, very steep sides. Has explosive eruptions. This eruption produces a lot of cinder and ash.

Strato or Composite Volcanoes

Strato volcanoes, also called composite volcanoes, erupt with molten lava, solid rock, and ash. The layers pile up much like layers of cake and frosting. The layers form into symmetrical cones, and the slopes are steep.

Composite Volcano Form from explosive eruptions. Produce a lot of lava and ash. Is small, with steep sides.

What’s inside a volcano? Magma Chamber- molten rock that feeds a volcano Vents- cracks in the crust What is the difference between magma and lava?

Types of Volcanoes Shield Volcano Built from layers of lava Non-explosive eruptions Not very steep, but can be big

Types of Volcanoes Cinder Cone Volcano Built from pyroclastic material Moderately explosive, short eruptions Small in size, steep slopes

Types of Volcanoes Composite Volcanoes Most common type Explosive eruptions and lava flow Built from pyroclastic material AND lava

What Erupts from a Volcano? Blocky lava Lava can be thick or thin. Pahoehoe Aa Pillow lava

What Erupts from a Volcano? Pyroclastic material Rock fragments created by eruptions magma explodes from volcano and solidifies in the air existing rock is shattered by powerful eruptions EXPLOSIVE Lapilli Volcanic bombs Volcanic blocks Volcanic ash

How do volcanologists predict eruptions? Measuring Small Quakes Before eruption, increase in number & intensity Measuring Slope Bulges may form with magma (tiltmeter) Measuring Volcanic Gases Outflow of volcanic gases Sulfur dioxide, carbon dioxide Measuring Temperature from Orbit Measure changes in temperature over time

There is much more about volcanoes out there There is much more about volcanoes out there. Look in books and on the internet . Have Fun!

Pictures, Images, and information From: Soames Summerhays/Photo Researchers, Inc. Kraft-Explorer/Photo Researchers Inc. Masao Hayashi-Dung/Photo Researchers Inc. Why Do Volcanoes Blow Their Tops? By Melvin and Gilda Berger www.usgs.gov/education/learnweb/volcano/index.html