Earthquake Vocabulary Notes

Causes of Earthquakes As the crust tries to move, pressure builds When crust finally moves, pressure and energy is released. Released as Seismic Waves.

Different Sized Earthquakes Bigger quakes release more pressure Smaller quakes release less pressure Pressure builds more when rocks in crust are very strong and bumpy. Since crust gets stuck and holds, more energy and pressure

2 Ways to Measure Earthquakes: 1.Richter Scale – Measures magnitude (strength) of quake. Based on how much energy is released. Each number on the Richter Scale represents an earthquake that is 10 times stronger. 3.0 magnitude is 10 times stronger than a 2.0 magnitude. 6.0 magnitude is 100 times stronger than a 4.0 magnitude.

2 nd way to measure an earthquake: 2. Mercalli Scale – Measures intensity (amount of damage) of quake. Describes what the quake would feel like. Roman Numerals.

Where Earthquakes happen (copy picture) 3. Focus - Point underground where land actually moves. Starting point of earthquake. 4. Epicenter – point on Earth’s surface directly above the focus. The earthquake feels the strongest here.

5. Seismic Waves (Review): Waves of energy that travel through the Earth during an earthquake. (Three types: P, S, and Surface waves) P and S waves travel into and through the Earth. 6. Surface Waves : The most destructive seismic waves, they travel across the surface of the Earth.