1. Earthquakes! I feel the Earth move…

2. What are they? Shakes Sways Trembles Vibrations

3. What causes them? Tectonic Plate Movement  Divergent Moving Away Creates a Ridge Example: Mid-Atlantic Ridge Lab Example: Crackers on the frosting  Convergent Coming Together Creates Volcanoes or Mountains Example: Aleutian Islands & Himalayas Lab Example: Cracker/Construction Paper & Soggy Crackers

4. What causes them?  Transform Sliding Against Fault Lines Example: San Andres Fault Lab Example: Grinding Crackers

5. Where do they happen? Earthquakes most commonly occur along plate boundaries.

6. How do they start? The two plates will begin to push and slide against each other  If one rock is weak, it will crumble and the plates will slide easily.  If both rocks are strong, the pressure will build until one finally breaks free.  Think of our fist/knuckles example.  Huge amounts of energy are released.

7. What is this energy? Seismic Waves  P Waves primary compress like a slinky fastest & loudest  S Waves shear follow the p waves causes surface to ripple  Surface Waves slowest & most destructive move like water ripples

8. Where is it really happening? Focus  The spot where the seismic energy is being released.  Though always underground, the location can be very shallow or very deep. Epicenter  The spot on the surface where the waves are the strongest.

9. Measuring Earthquakes Seismograph  picks up the vibrations made by an earthquake  recodes them as a wavy or spiked line  Zhang Heng created the first one

10. How do we measure them? Richter Scale  Charles Richter  Based on mathematical formula  Described the size or magnitude  Each number is 10 times more powerful than the one before it Mercalli Scale  Giuseppe Mercalli  Describes the damage  Looks at how much an object was shaken  Uses human based observations

11. Protection from Earthquakes Use materials that have more give like rubber.  In New Zealand flexible joints have been used for water pipelines. Use unconventional building bases.  Springs are placed under the building to absorb the shock.  A set of plates. The bottom plates rest on the ground. During a quake, only the bottom plates move, sliding back and forth under the top plates. Suspension Bridges: Allows the roadway to be hung from one or more towers which support the weight much like a hammock.