Why Does a Volcano Erupt?• What would happen if you were to stick a pin into a balloon? (it would burst)• Why does it explode?• Pressure inside the balloon is suddenly released and the gases escapes rapidly.• This is what happens in a volcano.
Volcanoes Ventsform around Lavavents thatrelease magmaonto the Earth’ssurface. Magma chamber
Types of Volcanic Eruptions1. Nonexplosive Eruptions have lava flow.1. Explosive Eruptions have lava fountains. •What is Lava? magma that flows onto the Earth’s surface •What is magma? Liquid rock from the mantle
What Erupts from a Blocky lava Volcano? 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 Lapilli Volcanic bombsVolcanic blocks Volcanic ash
How do volcanoes affect the Earth?Flows and Fallouts• hot ash can flow really quickly •Knock down buildings •Dam rivers (flooding/drought) •Kill crops and livestockClimatic Changes •Ash & Gases can block sunlight •Drop average global temperature noticeably
Where do volcanoes occur?•Divergent Plate Boundaries•Subduction Zones
What causes volcanoes?The Formation of Magma• Mantle rock melts when thetemperature increasesor the pressure decreases.
Where do Volcanoes Form? •Tectonic Plate Boundaries ~75% world’s active volcanoes in Ring of Fire
What Causes Volcanoes?•Hot Spots: areas of persistent volcanic activity•Originate at unusually hot areas of the mantle-core boundary.•Plumes of magma rise and poke through thecrust forming volcanoes
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
You should not be a • You don’t like Volcanologist if…. hiking, backbacking, rockclimbing, etc. • You are not interested in experiencing extreme temperatures and heights. • If you don’t like to travel to incredible places and see breathtaking views of the world.