Skip to main content
U.S. flag

An official website of the United States government

Earthquake Intensity Scale

Detailed Description

Earthquake Intensity - Modified Mercalli Intensity (MMI) Scale. 

The Modified Mercalli Intensity value assigned to a specific site after an earthquake has a more meaningful measure of severity to the nonscientist than the magnitude because intensity refers to the effects actually experienced at that place.

The lower numbers of the intensity scale generally deal with the manner in which the earthquake is felt by people. The higher numbers of the scale are based on observed structural damage. Structural engineers usually contribute information for assigning intensity values of VIII or above.


Public Domain.