Richter scale of earthquake magnitude


July 5, 2022

The Richter earthquake magnitude scale, also known as the local magnitude scale, M L {\displaystyle M_{L}} , is used as a measure of the amount of energy released in the hypocenter, when an earthquake occurs. It is a logarithmic scale, determined based on the calculation of the logarithm of the horizontal amplitude of the maximum displacement and the zero amplitude, on a horizontal torsional seismometer of the Wood-Anderson type. So, for example, an earthquake of magnitude 5 on the Richter scale has an amplitude of displacement that is 10 times greater than the amplitude of an earthquake of magnitude 4. The local magnitude determination limit is around 6.8. The Richter scale was developed in the 1930s. Although still in use, the Richter scale has been replaced by the moment magnitude scale, which generally gives the same values.

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Mercalli scale