FAULT

• Tectonic plates


  Large pieces of rocks that make up the Earth's crust
• Asthenosphere


  • Upper part of the mantle
  • Partly molten
  • Allows the movement of overriding plates at relatively slow rate
• Faults


  • Fracture along which blocks of rocks have moved
  • Found at the boundaries of tectonic plates
• Fault


  • Fault line - serves as the trace of the fault
  • Dip - angle that the fault cuts through the soil layers
  • Hanging wall block - portion above the fault
  • Footwall block - surface below the fault
• Types of faults


  • Dip-slip faults - movement of blocks is parallel to the dip of the fault surface
  • Normal faults - formed by tensional stresses that pull rocks apart, hanging wall moves down relative to the footwall, associated with divergent plate boundaries
  • Reverse faults - formed by compressional forces that push the plates towards each other, hanging wall moves upward relative to the footwall
  • Thrust faults - type of reverse fault whose dip is less than 40 degrees
  • Strike-slip faults - result of the sideways movement of blocks of rocks
  • Oblique faults - has both dip-slip and strike-slip components, formed by shear stress and tensional or compressional stress
• Horsts


  Uplifted/raised areas
• Grabens


  Dropped/lowered areas