Richter magnitude scale

The Richter magnitude test scale (or more correctly local magnitude ML scale) assigns a single number to quantify the size of an earthquake. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a seismogram. So, for example, an earthquake of magnitude 5 is ten times greater than one of magnitude 4 and an earthquake of magnitude 8 is 10(8-4) or 10000 times greater than one of magnitude 4.

See also

• List of earthquakes
• Mercalli Intensity Scale
• Moment Magnitude Scale