Subscribe to our newsletter. Remember that the Richter scale is not a physical device, but a mathematical formula. Intensity and Magnitude Scales Magnitude measures the energy released at the source of the earthquake. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded on a seismogram at a certain period. Intensity measures the strength of shaking produced by the earthquake at a certain location.
Intensity is determined from effects on people, human structures, and the natural environment.
The first reported use of any measurement of earthquake intensity has been attributed to the Italian Schiantarelli, who recorded the intensity of the 1783 earthquake that occurred in Calabrian, Italy. Rossi and Forel later collaborated and produced the Rossi-Forel Scale in 1883. The Rossi-Forel Scale used ten degrees of intensity and became the first scale to be widely used internationally. In 1902, Italian volcanologist Giuseppe Mercalli created a twelve-degree scale of intensity. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.