How does the Mercalli scale measure an earthquake

Difference between the Richter scale and the Mercalli scale

Richter Scale vs Mercalli Scale

Whenever an earthquake occurs (perhaps the deadliest of all natural disasters), experts use certain tools to measure the earth's seismic activity and measure the magnitude of the phenomenon. In this context, yardsticks such as Richter and Mercalli are used to give the public insight and take advanced forecasting and warning measures.

Scientists have developed methods to measure the intensity of earthquakes. As such, an earthquake can be measured either by basing it on the magnitude of the seismic energy or by studying the impact or intensity of the earthquake on the environment. For this reason, two popular scales have been developed. The Richter scale is the ideal barometer for assessing total seismic activity magnitude, while the Mercalli scale is used for quake intensity. Other similar scales can be used to measure intensity, such as the EMS scale, the MSK scale, the INQUA scale, and the Shindo scale. The scales most commonly used in America are the Richter and Mercalli scales.

Historically, the mercalli is an earlier scale that dates back to the 19th century. It was later modified by an Italian volcanologist named Giuseppe Mercalli in the early 1990s. Surprisingly, it was Charles Richter (the man who also designed the Richter scale) who was responsible for ensuring that it got its most modern form. Today the Mercalli scale is fully known as the MMI scale or modified Mercalli intensity scale.

As already mentioned, Charles Richter developed the Richter scale as early as 1935. With the help of Beno Gutenberg (one of his collaborators) the currently most popular and widely used seismic scale was created. This is most likely due to the fact that the Richter scale is more objective as it uses the results obtained by seismometers. Hence, numeric values ​​help create logarithms. In contrast, the Mercalli scale is much more subjective.

The Richter scale has a numerical range from 0 to 10. The weakest earthquakes usually have values ​​between 0 and 3.9. The middle tier quakes fall from 5-5.9, while the stronger quakes land anywhere from 6-6.9. The most powerful of all seismic activities are marked 7 or more. In contrast, the MMI has 12 intensity levels, with level 1 being the lowest level of alert, characterized by minor tremors perceived by seismic instruments. The highest of these is level 12, which is known as total destruction. Hence it is known for its other term "cataclysmic plane".


1. The Richter scale measures the magnitude of the earthquake activity of an earthquake and other areas that can be measured numerically.
2. The Mercalli scale measures the intensity of the earthquake.
3. The Mercalli scale is an older scale that is older than the Richter scale.
4. The Richter scale is used more often than the Mercalli scale.
5. The Richter scale is more objective than the more subjective Mercalli scale.