Chapter 5 section 1 Objective: Determine where earthquakes come from and what causes them Identify different types of earthquakes Describe how earthquakes travel through the earth. Seismology Where do Earthquakes occur? Is the study of Earthquakes. Tectonic plates move – In different directions – In different speeds

Fault Break in the Earths crust along which blocks of the crust slide relative to one another. – Common near the edges of tectonic plates

What cause Earthquakes? Deformation Stress builds up along the fault as a result of the push and pull of tectonic plates. Is the change in the shape of the rock in response to the stress.

Two types of deformation – Plastic deformation – Elastic deformation Does not lead to earthquakes Does lead to earthquakes. (rubberband) Stretching releasing energy

Elastic rebound Sudden return of elastically deformed rock to its original shape.

Seismic waves Body waves Seismic waves are released from the rock when it springs back from being deformed. Seismic waves that travel through the Earth

Two types of body waves – P Is for primary (fastest) – Travel through solids, liquids, and gases. – First seismic waves to be detected. – presssure

S Surface Waves S is for secondary – Second fastest – Shear a rock back and forth – Surface waves move the ground up and down in circles as the waves travel along the surface.

Surface Wave Most damage Feels like you are on a roller coaster.