Inside EarthChapter 3 Volcanoes

3.1 Volcanoes and Plate Tectonics

3.1 Volcanoes and Plate TectonicsKey Concepts

Where are most of Earth’s volcanoes found?How do hot spot volcanoes form?

3.1 Volcanoes and Plate TectonicsKey Terms

• Volcano – A weak spot in the crust where magma has come to the surface.

• Magma – The molten mixture of rock-forming substances, gases, and water from the mantle.

• Lava – Liquid magma that reaches the surface. Also the rock formed where liquid lava hardens.

3.1 Volcanoes and Plate TectonicsKey Terms

• Ring of Fire – A major belt of volcanoes that rims the Pacific ocean.

• Island arc – A string of island formed by the volcanoes along a deep-ocean trench.

• Hot spot – An area where magma from deep within the mantle melts through the crust above it.

Divergent Plate Volcanoes

• At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock.

Divergent Plate Volcanoes

Convergent Plate Volcanoes

• Subduction zones are places where oceanic plate dives beneath continental plate. The oceanic crust melts creating magma. When The magma reaches the surface, a volcano is formed.

• Ring of fire

Convergent Plate Volcanoes

Ring of Fire

Hot Spot Volcanoes

• "Hotspots" is the name given to volcanic areas believed to be formed by very hot locations in the earths mantle.

• Hawaii - was formed this way

Hawaii Hot Spot