Tectonic Plates

1
Tectonic PlatesKeep on Moving

• For hundreds of millions of years, the forces
  of Plate Tectonics has shaped the Earth.
• As Tectonic Plates slowly move over, under
  and past each other, they build mountains, form
  new sea floor, create earthquakes and volcanoes.

2
EarthquakesEarths Way of Releasing Stress

• An earthquake is a sudden movement of the Earths
  crust caused by the abrupt release of
  stresswhich has built up over a long time.

3
Earthquake Faults

• When enough stress builds in the Earths crust,
  the rock breaks, creating a fault.
• A fault is a break in Earths crust where slabs
  of crust slip past each other

4
Where Faults Happen

• Faults often occur at plate boundaries - but not
  always. They can appear in the center of a plate!
• Each type of fault is often associated with a
  specific type of plate boundary.
• It is possible for more than one type of fault to
  happen on one plate boundary.

5
Three Main Types of Faults

• 1. Strike-Slip Fault - associated with Transform
  Boundaries.
• 2. Normal Fault - associated with Divergent
  Boundaries.
• 3. Reverse Fault - associated with Convergent
  Boundaries.

6
Strike-Slip Fault

• Vertical fault, blocks slide past one another
  horizontally.
• Happens in areas where the crustal blocks are
  sliding past one another.
• Created by shearing stress.
• Example San Andreas Fault

7
Normal Fault

• The fault is at an angle, and the block above the
  fault, the hanging wall moves down relative to
  the block below the fault (the foot wall).
• Occurs in areas where there is pulling of the
  crustal blocks.
• Caused by tension stress.

8
Reverse or Thrust Fault

• The fault is at an angle, and the hanging wall
  moves up relative to the foot wall.
• Same structure as normal fault, but the blocks
  move in opposite direction.
• Happens in areas where the crustal blocks are
  being pushed together.
• Caused by compression stress.