1. Locating an earthquake
The difference in velocities of a P wave and S wave provides a way to locate the epicenter
Use a travel-time graph
Need at least three seismograph station data

2. Intensity and Magnitude of Earthquakes
Two different types of measurements to describe the size of an earthquake (intensity and magnitude)
Intensity
A measure of the amount of earthquake shaking at a given location based on the amount of damage
Magnitude
A measure of the size of seismic waves or the amount of energy released at the source of an earthquake

3. The Scales Richter Scale Measures the magnitude of an earthquake
Based on the amplitude of the largest seismic wave
10-fold system (ex: The amount of shaking for a 5.0 earthquake is 10 times greater than the shaking produced by an earthquake of 4.0 on the Richter Scale

4. The Scales Moment Magnitude
More precise means of measuring earthquakes
Amount of displacement that occurs along a fault zone
Calculated using several factors
Average amount of movement along the fault
Area of the surface break
Strength of the broken rock
Most widely used measurement for earthquakes because it is the only magnitude scale that estimates the energy released by earthquakes

5. Destruction from Earthquakes
Seismic Vibration-Damage to building depend on several factors
Intensity and duration of vibration
Nature of the material on which the structure is built
Design of the structure
Liquefaction
Stable soil turns into a liquid that is not able to support buildings or other structure

6. Tsunami Seismic sea waves
Triggered by an earthquake occurring where a slab of the ocean floor is displaced vertically along a fault
tsunami videos

7. Other Dangers Landslides Fires
Sinking of the ground triggered by the vibration
Greatest damage to structures
Fires
Caused by ruptured gas lines

8. Predicting Earthquakes
Short range
Methods for short range predictions of earthquakes have not been successful
Long range
Based on the idea that earthquakes are repetitive
Seismic gap: an area along a fault where there has not been any earthquake for a long-period of time

9. Virtual Earthquake http://www.sciencecourseware.com/eec/Earthquake/
Main Activities: Time travel Graph
Recommended: Tutorials (top right)
Tasks – use different tools to gather and record in journal at bottom of screen
Show teacher after you verify your answers
Main Activities: Epicenter and Magnitude