Stress & Strain

• Incompetent Rock Example

  Mudstone, Shale, Clay
• Competent Rock Example


  Anything except Mudstone, Shale, Clay
• Compressional Force


  Reverse, Antiform/Synform
• Tensional Force


  Normal Fault, no fold
• Shearing Forces


  Strike-Slip, Antiform/Synform
• What is Stress?


  Is the force per unit area acting on a rock, measured in Pa (N/M2)
• What is Strain


  A deformation, a change in vol or shape
• Increasing Pressure


  Rock strength increases pressure - less likely to fault
• Increasing Temp


  Creates ductile behaviour -> more effect than pressure
• Water


  Weakens rock - faults sooner

  Reduces friction = ductile behaviour
• Time


  Short period of time = brittle

  Long period of time = plastically