Section 3: Internal Forces Shaping the Earth

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Section 3 Internal Forces Shaping the Earth

• 1.The earths crust consists of number of
  tectonic plates

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• 2. tectonic plates - enormous moving pieces of
  the earths lithosphere
• (p. 37)

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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

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• 3. Movement
• of the plates
• produces
• earthquakes
• and volcanoes
• Fault fracture in the earths crust where
  plates move past each other

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• Earthquake - Violent movement of the earth as the
  plates grind or slip past each other at a fault
• Seismograph a device that measures the size of
  the waves created by and earthquake

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Epicenter

• Point directly above the focus of an earthquake
  on the earths surface
• Richter Scale uses information collected by
  seismographs to determine the strength of an
  earthquake

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Tsunami

• A giant wave in the ocean caused by an
  underground earthquake

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Volcanoes crack in the earths surface where
magma and gases pour out
Lava magma that has reached the earths surface
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The Ring of Fire

• The most active volcano and earthquake zone on
  earth

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External Forces Shaping the Earth

• Weathering and erosion alter the surface of the
  earth
• Weathering physical and chemical processes
  that change the characteristics of rock on or
  near the earths surface

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• Sediment - Small pieces of rock created by
  weathering (mud, sand or silt)
• Mechanical Weathering processes that break rock
  into smaller pieces (doesnt change the
  composition of rock, but the size)
• example road construction

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• Chemical Weathering occurs when rock is changed
  into a new substance as a result of interaction
  between elements in the air or water and minerals
• (example iron rusting)

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Erosion

• Occurs when weathered material is moved by the
  action of wind, water, ice and gravity

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• 2. Water, wind, and glaciers cause erosion

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wind erosion
Loess windblown silt and clay sediment that
produces very fertile soil
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Water Erosion

• Delta sediment is deposited in a fan-like
  landform when a river enters an ocean

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Glacial Erosion

• Glacier a large, long-lasting mass of ice that
  moves because of gravity
• Glaciation changing of landforms by slowly
  moving glaciers
• Moraine rocks left behind from a glacier that
  form a ridge or hill

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Glacier
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Moraine
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• 3. Weathering and erosion help form soil
• Soil Factors
• Parent Material
• Relief
• Organisms
• Climate
• Time