Volcanoes

Volcano a mountain that forms when molten rock, called magma, is forced to the Earth’s surface

Magma Mixture of hot, liquid rock and solid mineral crystals Called lava, once it flows onto the Earth’s surface

Potential & Kinetic Energy Potential Energy – magma builds up pressure beneath the volcano Kinetic Energy – when enough pressure builds up, energy is released as volcano erupts to restore equilibrium

Ring of Fire Known for its earthquakes, volcanoes, and tsunamis Where 75% of the Earth’s volcanoes occur Area around the Pacific Ocean

Ring of Fire The whole Ring of Fire stretches for 40,000 km in length.

Mount St. Helens On Sunday May 18, 1980 Mount St. Helens erupted. It started with an earthquake (5.1 magnitude) about one mile beneath the volcano, and the north side of the mountain collapsed. Nearly 230 square miles of forest was blown down or buried beneath lava and volcanic debris.

Day turned into night as a mushroom- shaped cloud of ash rose thousands of feet into the sky and dark, gray ash filled the air in eastern Washington. The eruption lasted 9 hours, and Mount St. Helens and the surrounding environment were dramatically changed within moments.

Mount St. Helens Before & After

Trees were flattened by the sheer force

Mount St. Helens Picture in 2004 showing the ecological succession (regrowth) since the eruption of Mount St. Helens.

Effects (Ash and gases are blasted into atmosphere) Blasts can blow down trees and nearby buildings Hot ash can choke and burn every living thing in its path Destruction of crops can cause food shortages and loss of livestock

Effects Ash can block out the sun for weeks or much longer. Ash can cause average global temperatures to drop (this may last for years). This would bring milder summers and colder winters.

Mt. Vesuvius On August 24, 79 AD Mount Vesuvius erupted. It spewed tons of molten ash, rock and sulfuric gas miles into the atmosphere.

Poisonous gases and magma engulfed the area suffocating the inhabitants and neighboring cities of Pompeii, Herculaneum, and Stabiae. The cities remained buried and undiscovered for almost 1700 years until excavation began in 1748.

Mayon Volcano in Phillipines Phillipine’s most active volcano. Picture taken on December 15, Authorities worked evacuate over 50,000 people because a large eruption was predicted.

Mayon's most violent eruption was 1814, and more than 1,200 people died and several towns were devastated. Its last major eruption was in Since then, it has emitted ash and spewed lava but remained restless.

How can scientists predict volcanoes? measure small quakes – as magma rises the surrounding rocks move, just before eruption will have many small quakes measure slope – as magma moves upward it will cause bulges in the sides of a volcano

How can scientists predict volcanoes? measure volcanic gases – a change in the ratio of volcanic gases can indicate an eruption is near measure temperature from orbit – as the magma gets closer to the surface the temperature of the volcano increases which indicates an eruption could happen soon