Internal Forces - Changes Within the Earth

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Internal Forces - Changes Within the Earth
8/26-8/27 Chapter 1, Pgs. 50-55 Most of this is
NOT in your book!
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May the force be within the Earth!
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Q What is geology? A The study of the earths
physical structure and history.
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• What does the inside of the earth look like?
• Core Consists of very hot metal, mainly iron
  mixed with some nickel. Inner core is thought to
  be dense and solid. Outer core is molten or
  liquid.
• 2. Mantle A thick layer of rock. About 1800
  miles thick. Contains pockets of magma or melted
  rock.

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1. Crust Rocky surface layer. Like frosting on a
   cake. 5 to 22 miles thick. Natural forces
   interact with and affect the earths crust,
   creating landforms.

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Q How much of the earth is water? A 70 of
earth is covered with water. Four Major Types of
Landforms Mountains Hills Plateaus Plains
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• Landforms are shaped by the internal forces that
  originate in the earths interior
• Volcanism
• 2. Earthquakes

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Volcanism movement of magma inside the earth,
when molten rock (lava) inside the earth breaks
through the earths crust it forms a volcano
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Earthquake movement of rock layers that bend or
break the earths crust. Folds and faults occur.
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Q How do we explain these folds/faults? A The
Plate Tectonics THEORY The earths outer shell
(mantle and crust) is composed of large plates
whose slow and steady movement explains
earthquakes and volcanic activity.
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The Plate Tectonics Theory is based in two other
theoriesContinental Drift Theory and the
Seafloor Spreading Theory.
Continental Drift Theory Theory proposed by
Alfred Wegener in 1912, where he suggested the
idea that over - - - - - - - - - - - gt
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Pacific Ocean Ring of Fire

• Humans encounter tectonic forces most directly as
  earthquakes and volcanoes
• Volcanoes and earthquakes are particularly common
  around the edges of the Pacific Ocean
• Area is known as the Ring of Fire

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Four Major Types of Plate Movement
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1. Subduction Oceanic plate goes under a
continental plate.
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2. Converging Two continental plates meet each
other creating mountains.
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3. Faulting Plates moving past each other
creating earthquakes.
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4. Seafloor Spreading The ocean floor is not
flat. Molten rock (magma) from the mantle rises
up to the underwater ridges and breaks through a
split at the top of the ridge - called a rift
valley. Example Mid-Atlantic Ridge
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Sea-Floor Spreading
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The End
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Plate Tectonics Map Assignment
http//www.worldatlas.com/aatlas/infopage/tectonic
.htm