Movements of the Crust: How they change landforms.

Earth has four layers-the crust, the mantle, the outer core, and the inner core.

Some rock within the mantle is soft, like melted candy.

Plates “float” on the softer rock of the mantle Plates “float” on the softer rock of the mantle. See the plates move at: http://www.ucmp.berkeley.edu/geology/tectonics.html

Earthquakes are caused by a sudden release of energy in the Earth’s crust, caused by plate movement.

Most earthquakes occur along a fault; most faults are found along the edges of plates.

A break in the Earth’s crust fault A break in the Earth’s crust

The strength of an earthquake is measured using the Richter scale.

An earthquake measuring 6.0 or higher can cause a great deal of damage.

A mountain made of lava, ash, or other materials from eruptions. volcano A mountain made of lava, ash, or other materials from eruptions.

Molten rock under Earth’s surface is called magma Molten rock under Earth’s surface is called magma. It is called lava once it flows out of the volcano.

Mt. St. Helens: Composite Before After

Mauna Loa: Shield Inactive day Active day

Paricutin: Cinder Cone 1943 today

How the Hawaiian islands formed:

Mountains form when plates collide. Oceanic and Continental Continental and Continental