1. Earthquakes

2. An Earthquake is…
The movement of Earth's plates produces strong forces that squeeze or pull the rock in the crust. We feel this as shaking and trembling.
Stress is a force that acts on rock to change its volume or shape
Deformation is the disruption of the original form of rocks

3. 3 Types of Stress
There are three different types of stress that occur on the crust, shearing, tension, and compression
These forces cause some rocks to become fragile and they snap
Some other rocks tend to bend slowly like road tar softened by the suns heat

4. Faults
A fault is a break in the crust where slabs of crust slip past each other. The rocks on both sides of a fault can move up or down or sideways
When enough stress builds on a rock, the rock shatters, creating faults
Faults usually occur along plate boundaries, where the forces of plate motion compress, pull, or shear the crust too much so the crust smashes

5. Seismic Waves
Seismic Waves: vibrations that travel through Earth carrying the energy released during an earthquake
an earthquake produces vibrations called waves that carry energy while they travel out through solid material
During an earthquake, seismic waves go out in all directions to the focus
They ripple like when you through a stone into a lake or pond

7. Seismic Waves Ctd.
There are three different types of seismic waves: Primary waves, Secondary waves, and surface waves

8. Magnitude The Richter Scale
-The amount of damage created by an earthquake depends on several factors.
-Measures an earthquake’s strength
Magnitude
-Number that represents the measurement of an earthquake on the Ricter Schale

9. Tsunamis
Earthquakes which occur on the ocean floor produce giant sea waves called tsunamis. Tsunamis can travel at speeds of 700 to 800 km per hour. As they approach the coast, they can reach heights of greater than 20 meters.

10. Formation of a Volcano

11. Magma
Deep within the Earth, under tremendous pressure and at great temperatures, rock exists as a hot liquid called magma. This molten rock is found in pockets called magma chambers.

12. Lava
When the magma reaches the surface, it is called lava.

13. Four types of lava.
Dark-Colored Lava - contains a lot of water. This is rich in iron and magnesium and cools to form igneous rocks such as basalt. Light-Colored Lava - contains little water and is rich in silicon and aluminum. Combination - similar to both the dark-colored type and the light-colored type Gaseous Lava - gases such as steam and carbon dioxide

14. Ring of Fire
One major earthquake and volcano zone extends nearly all the way around the edge of the Pacific Ocean.

15. Mediterranean Zone
A second Major earthquake and volcano zone is located near the Mediterranean Zone and extends across Asia into India. Many countries in the zone, including Italy, Greece and Turkey, have violent earthquakes.

16. Mid-Atlantic Ridge Zone
The third major earthquake and volcano zone extends through Iceland and to the middle of the Atlantic Ocean. There is under the ocean a long range of volcanic mountains called the Mid-Atlantic Ocean Range.