Volcanoes For Grade 7

Any opening in Earth's crust through which molten rock and other materials erupt.

They prove that deep within our planet there are termendous forces at work.

Most earthquakes and volcanoes are found along the edges of the Earth's plates.

Most earthquakes and volcanoes

Only a few volcanoes are found away from the edges of plates.

1. Some volcanoes erupt frequently and relatively quietly. 2.Other volcanoes only erupt once every few hundred year with massive explosions. 3. Many volcanoes go unnoticed at the bottom of oceans.

Volcanoes at divergent boundaries Volcanoes at convergent boundaries Volcanoes at hot spots

1. 3/4 of all of the earth's lava is produced on earth from eruptions at divergent boundaries of the ocean. 2.Magma pushes to the surface where plates are moving apart. 3. The lava erupts and cools to form a ridge on each side of the crack on the ocean floor. 4. Some of the ridges may rise high enough to reach the surface creating islands. 5. Iceland was formed in this way

It is a ridge in the middle of the Atlantic Ocean formed by magma pushing two plates apart.

In 1963 plumes of smoke billowed out of the ocean near Iceland. Soon a new island appeared, as large amounts of magma flowed out of the ocean rift between the Eurasia and North American Plates, Eventualy the island grew to 150m above sea level. This new island was caled Surtsey after Surt the lord of the land of fire giants,

Europe: Surtsey and Iceland BC: Mount Edziza, Hoodoo Mountain, Lava Fork and Crow Lagoon They are in North Western BC and they last erupted 150 years ago.

They are located at Conevrgent Boundaries.

1. Most of the volcanoes on land are near convergent plate boundaries. 2. Most powerful eruptions occur where one plate is being subducted under another plate. 3.The magma that is formed in a subduction zone is thick and sticky. 4. Since the magma is too still to allow steam and volcanic gases to escape tremendous pressure builds up. 5. When the pressure is released the volcano erupts explosively. 6. As the lava reaches the surface, the high pressure steam escapes, carrying with it lava and ash.

Mount Meager (near Whistler), Mount Silverthorne, Mount Cayley, Mount Garibaldi and Mount St. Helens. They are all near the convergent boundary where the Juan de Fuca plate is being subducted under the North American plate. Mount St. Helens erupted in 2004 and Mount Meager erupted 2000 years ago.

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