Internal Forces Shaping the Earth The earth’s crust consists of number of tectonic plates
The theory of continental drift 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
Example-Hawaiian Islands, Galapagos Islands 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