What Is the Richter Scale?

Answer:

In 1935 an American seismologist, Charles F. Richter, devised a numerical scale for rating the strength of earthquakes. Each successive number in the scale represents a tenfold increase in the amount of energy released by a quake. An earthquake rated 2 releases 10 times as much energy as a quake rated 1, for example, and a 3 is 10 times stronger than a 2.

Seismographs record hundreds of minor tremors each day, but magnitudes of less than 2 are not noticeable by humans. Structural damage is unlikely unless an earthquake rates a 5 or more. Severe earthquakes are in the 7-and-up category. The truly great earthquakes are the few with magnitudes of more than 8.