What is the Richter Magnitude Scale?

The Richter magnitude scale, also known as the local magnitude (M) scale, assigns a number to quantify the amount of seismic energy released by an earthquake. It is a base-10 logarithmic scale.

Richter magnitude Description Earthquake effect
< 2.0 Micro Micro earthquakes, not felt.
2.0-2.9 Minor Generally not felt, but recorded.
3.0-3.9 Often felt, but rarely causes damage.
4.0-4.9 Light Noticeable shaking of indoor items, rattling noises. Significant damage unlikely.
5.0-5.9 Moderate Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings.
6.0-6.9 Strong Can be destructive in areas up to about 160 kilometres (100 mi) across in populated areas.
7.0-7.9 Major Can cause serious damage over larger areas.
8.0-8.9 Great Can cause serious damage in areas several hundred miles across.
9.0-9.9 Devastating in areas several thousand miles across.
10.0+ Epic Never recorded