There are two basic ways to measure the strength of an earthquake: (1) based on the earthquake
magnitude and (2) based on the intensity of damage. Magnitude measures the
amount of energy released from the earthquake, and intensity is based on the damage to
buildings and reactions of people. This section discusses earthquake magnitude, and Sec.
2.5 discusses the intensity of the earthquake.
There are many different earthquake magnitude scales used by seismologists. This section
discusses three of the more commonly used magnitude scales.