Geology Final Exam: Earthquakes

The vibration of Earth produced by the sudden release of energy due to the sudden movement along a fault.

The geographic point on Earth’s surface directly above the focus of an earthquake.

The point along a fault at which slipping initiates an earthquake.

Records Earth's movement relative to a stationary mass.

Seismic Waves

• Primary (P) Waves
• Secondary (S) Waves
• Surface (L) Waves

Primary (P) Waves

Surface (L) Waves

1) Determine time interval between arrival of P and S wave (lag time)

2) Use travel time graph to determine distance from epicenter

3) Draw circle with radius equal to distance to epicenter around each station. Repeat for 3 stations

4) Epicenter is the point where all three circles intercept

• Mercalli Intensity scale
• Measures the intensity of an earthquake from the amount of damage it causes.

• Richter Scale
• Developed for shallow, local earthquakes and does not work well for large earthquakes. Based on amplitude of largest seismic wave.

Destruction is not always a true measure of an earthquake's actual severity.

-Shaking

-Liquefaction of the ground (Solid earth liquifies -unsaturated mud)

-Seiches (Rhythmic slashes of water)

-Tsunamis (Seismic sea waves)

-Landslides

-Fires