Unlike with the Richter scale, the Mercalli scale does not take into account energy of an earthquake directly. Rather, they classify earthquakes by the effects they have (and the destruction they cause). When there is little damage, the scale describes how people felt the earthquake, or how many people felt it.

How is the Mercalli scale measured?

The Mercalli scale bases its measurement on the observed effects of the earthquake and describes its intensity. ... The calculation for the Mercalli scale is quantified from the observation of the earthquake's effect on the earth's surface. It is also based on the effect on humans, objects, and man-made structures.

What is the purpose of a Mercalli scale?

The modified Mercalli intensity scale (MM or MMI), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake.