Definition: a tremor of the surface of the earth, sometimes minor and unnoticed, but sometimes severe and devastating.
Cause: sudden shifts of earth's crust along faults.
Land forms created by earthquakes:
mountains, valleys, and fault scarps
How to measure the strength of an earthquake: seismograph; Richter Scale
How to predict an earthquake:
1. observe the movements of tectonic plates and the location of fault zones;
2. Study the earthquake history of a certain area and make guesses about when the next one might occur based on a pattern.