Internal Forces Shaping the Earth

The earth’s crust consists of number of tectonic plates

• The crust is broken into different ‘plates’• These parts of

the Earth's crust slowly drift atop a liquid mantle

tectonic plates - enormous moving pieces of the earth’s lithosphere

Types of boundary movements:

• Divergent – plates move apart, spreading horizontally• Convergent – Plates collide, causing

either one plate to dive under the other or the edges of both plates to crumple• Transform – plates slide past each other

YouTube Video

• http://www.youtube.com/watch?v=ryrXAGY1dmE

Movement of the plates produces earthquakes and volcanoes

• Fault – the boundary between two plates

• A crack in the earth’s lithosphere

Volcanoes –a mountain with a crater through which lava, rock fragments, hot vapor, and gas are being or have been

erupted from the earth's crust.

Volcanic Eruptions• Lava – magma that has reached the earth’s

surface• Most volcanoes erupt with volcanic ash,

which makes the area great for farming.• The volcanic ash can also create it’s own

weather

Hot Spots•narrow stream of hot mantle coming up from the mantle through the crust.•Creates chains of volcanoes as the plate moves across the hot spot.•These volcanoes are not on plate boundaries

•Example-Hawaiian Islands, Galapagos Islands

The Ring of Fire• The most active

volcanic and earthquake zone on earth• The Ring of Fire has

452 volcanoes and is home to over 75% of the world's active and dormant volcanoes.

Earthquake - Violent movement of the earth as the plates grind or slip past each other at a fault

YouTube Video:

http://www.youtube.com/watch?v=xyKgamjegtQ

Tsunami• A giant wave in the ocean caused by

an underwater earthquake

• i. Seismograph – a device that measures the size of the waves created by and earthquake

ii.Epicenter• Point directly above the focus of an

earthquake on the earth’s surface

• iii. Richter Scale – uses information collected by seismographs to determine the strength of an earthquake