Section 3 Theory of plate tectonics

Plate tectonics  The theory that the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere.

Convergent boundary  When to tectonic plates push into one another.

Divergent boundary When two tectonic plates move away from one another.

Transform boundary When two tectonic plates slide past each other

Section 4 Deforming the Earth’s Crust

Stress is the amount of force per unit area

Compression  The type of stress that occurs when an object is squeezed

Tension  Is stress that occurs when forces act to stretch an object

Folding  Occurs when rock layers bend due to stress in the Earth’s crust

Fault  A break in the Earth’s crust along which blocks of the crust slide relative to one another due to tectonic forces

Normal fault  A fault in which the hanging wall moves down relative to the footwall

Reverse fault  A fault in which the hanging wall moves up relative to the footwall

Strike-slip Fault  Occurs when opposing forces cause rock to break and move horizontally