Moment magnitude scale

The moment magnitude scale is a way to measure the power of earthquakes. It is the energy of the earthquake at the moment it happens. Like the similar and older Richter scale, it is logarithmic, with a base of ten. This means that an earthquake with a magnitude of 2 is ten times stronger than an earthquake with a magnitude of 1.

Scale Number	Earthquake Effect
less than 3.5	This would be a very weak earthquake. People would not feel it, but it would be recorded by geologists.
3.5-5.4	Generally felt by people, but it rarely causes damage.
5.4-6.0	Will not cause damage to well-designed buildings, but can cause damage or destroy small or poorly-designed ones.
6.1-6.9	Can be destructive in areas up to about 100 kilometers across where people live.
7.0-7.9	Considered a "major earthquake" that causes a lot of damage.
8 or greater	Large and destructive earthquake that can destroy large cities.

Related pages

• Mercalli intensity scale
• Richter scale

Other websites

• What is Richter Magnitude?