EaRtHqUaKeS!!!

Seismology: the study of earthquakes

Most earthquakes take place near the edges of tectonic plates (most active earthquakes occur along the plates surrounding the Pacific Ocean)

What Causes Earthquakes? Deformation is the change in the

shape of rock in response to stress. Rock can deform in 2 ways:

- plastic- elastic

Plastic Deformation Stress causes the crust on one side of

a fault bend like clay

THIS DOES NOT LEAD to EARTHQUAKES!!!!

Elastic Deformation Rock can only stretch so

far before it will break

Like a rubber band, when it breaks, energy is released and the broken pieces return to their unstretched shape causing energy to spread through the earth in waves

Are All Earthquakes the Same?

No. Depending on the type of plate boundary, earthquakes can be strong or weak.

Plate Motion Earthquake Characteristics

Transform Moderate, shallow

Convergent Strong, deep

Divergent Weak, shallow

How Are Earthquakes Measured?

This is a seismograph It is an instrument located at or near

the surface of the Earth that records seismic waves

What Scale is Used to Measure the Strength of an Earthquake?

The Richter ScaleMagnitude Estimated Effects

2 Can only be detected by a seismograph

3 Can be felt at the epicenter*

4 Felt by most in the area

5 Causes damage at the epicenter

6 Causes widespread damage

7 Causes great, widespread damage

* Right where the earthquake begins

Earthquakes Popsicle stick activity

• How did the stick change before it broke?• How might rocks react to pressure?

Faults