The Richter scale was developed in the 1940s by American scientists Beno Gutenberg and Charles Richter in order to gauge scientifically the intensity of individual earthquakes.
The idea behind the Richter scale is that the energy released by an earthquake should be measured, not its effect on Earth’s surface. The Richter scale provides an accepted standard of measurement, based on seismographic recordings.
The Richter scale ranges from 0 to 9.0. Earthquakes of 2 or lower are imperceptible. The 9.0 ceiling is simply a reflection of how intense earthquakes have been in the past. If there were to be an earthquake stronger than any before, the scale would reach higher to encompass it.
One important element of this scale is that the levels increase exponentially. Each notch up the scale represents 10 times the motion and 30 times the energy of the previous level.
For example, an earthquake registering 7.5 has 10 times the ground motion and 30 times the released energy of a 6.5 earthquake. An 8.5 earthquake has 100 times the ground motion and 900 times the released energy of a 6.5 quake.
Earthquakes greater than 8.9 release energy millions of times greater than the first atomic bomb.