3 Types of Stress

• Stress are forces that push, pull, or twist the crust
• Strain is any change in volume or shape
• 3 Types of Stress:

  • Tension
  • Compression
  • Shearing
• Tension Stress: This type of stress pulls on the crust, stretching rock, lengthens it
• Compression: This type of stress squeezes rock until it folds or breaks at convergent plate boundaries
• Shearing: This type of stress pushes a mass of rock in two opposite directions. Shear stress is the most common stress at transform plate boundaries
• 3 Possible responses:

  • elastic deformation
  • plastic deformation
  • fracture
• Elastic deformation- the rock returns to its original shape when the stress is removed
• Plastic deformation- the rock does not return to its original shape when the stress is removed
• Fracture- the rock breaks
• Seafloor spreading is a geologic process where tectonic plates split apart from each other