Erosion by Gravity

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Erosion by Gravity
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What is gravity?

• Gravity is the attraction force between two
  objects with masses. Objects on the earth and
  the earth itself are the most common masses when
  talking about gravity.

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Mass movement

• Gravitys effect on land erosion is due to the
  angle of the land.
• Have you ever noticed that some objects will
  stick to a surface until you reach a certain
  angle?

4
Friction

• When objects are on a slant and do not fall, they
  are often held by friction. However, certain
  other objects (such as water, oil, or grease)
  reduce the amount of friction and can aid in
  gravitys effect on erosion.

5
A rock fall

• A rock fall happens when a group of loose rocks
  falls down a steep slope.

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Landslides

• A landslide is the sudden and rapid movement of
  material.
• California suffers landslides when the water
  table creates slumps in mountain sides and the
  supporting rock becomes weak.
• 1995 landslide in La Conchita, California ?

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Mud flows

• Mud flows are rapid movements of mud. Muds can
  be very damaging because they act like a
  combination of a flood and a landslide.

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Creep y?

• A creep is an extremely slow movement of material
  down slope.
• Often you can notice bent trees on a creep.

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Review

• For the rest of class complete the following
  review
• Page 300
• Multiple choice 7-16
• Short answer 17-22
• Critical thinking 24 and 27