Earthquake sizes are measured on magnitude scales, the most well known of which is the Richter magnitude scale, which assign a number based on the seismic energy of an earthquake. The most accurate scale now used is the moment magnitude scale which is very similar to the Richter scale, and provides measurements in the same numerical category system.
The media and the public generally refer to earthquake measurements as the Richter scale. Technically the original equations are no longer used, but the scale system remains basically the same. The scale ranges from 0 - 10+, with 0-2.5 being earthquakes that generally aren’t felt but are recorded by seismographs, and 10+ being extreme earthquakes that have not occurred in recorded human history. Earthquakes from 2.5-5.4 are usually felt but do very little damage. The vast majority of earthquakes that occur are between 0 and 5.5 in scale. Earthquakes that measure 8 or more on the scale are considered Great earthquakes and are extremely destructive.
Earthquakes have 7 magnitude classes:
