Measuring Magnitude

In 1935, Dr. Charles Richter developed a numeric scale for measuring an earthquake's magnitude (the amount of energy it released). 

Though people still refer to the "Richter scale," more advanced scales are now in use. But no matter what the scale, geologists determine an earthquake's magnitude by looking at the size of the seismogram it made. The larger the seismogram, the greater the shaking; the greater the shaking, the greater the magnitude.