The Richter Magnitude Scale
In 1934, a California Geologist named Charles F. Richter came up with a better idea. His method,
known as the "Richter Magnitude Scale" uses a scientific logarithm to determine the magnitude of an
earthquake by measuring the acceleration of the ground during a shock. This method, of course,
requires the use of scientific instruments to measure the variables used in the formula.
The Richter Scale, as it is now widely known, is an open-ended scale. That is to say there is no top
end to it. However, the magnitude of the strongest quake ever recorded (Chili, 1960) was around 9.0
on Richter's Scale. As a sidebar, it has been estimated that it would take an explosion of 200 million
tons of TNT to match the energy expended in that quake.
The interesting thing about the Richter Scale is that for each incremental rating of one that an
earthquake scores, its strength or energy is actually multiplied by a factor of 10. So a 6.0 quake has
10 times the energy of a 5.0 quake. (The amount of energy that theoretically would be released in a
magnitude 12 earthquake would equal 1 trillion tons of TNT and would be sufficient to fracture the
earth in half through its center!)
The Richter Scale
Magnitude
Effects
less than 2.5 Usually not felt, but can be recorded by seismograph
Estimated Number Per
Year
900,000
2.5 to 5.4
Often felt but only causes minor damage
5.5 to 6.0
Slight damage to structures
500
6.1 to 6.9
May cause much damage in populated areas
100
7.0 to 7.9
Major earthquake; serious damage
20
8.0 or
greater
Great earthquake; can totally destroy communities near
the epicenter
http://www.fcgov.com/oem/richter-scale.php
30,000
One every 5-10 years