His motivation for creating the local magnitude scale was to separate the vastly larger number of smaller earthquakes from the few larger earthquakes observed in California at the time. (Many scientists and historians feel it should be known as the Richter–Gutenberg scale.) Richter originally reported values to the nearest quarter of a unit, but decimal numbers were used later. ĭeveloped in 1935 by Charles Richter in partnership with Beno Gutenberg, both of the California Institute of Technology, the scale was firstly intended to be used only in a particular study area in California, and on seismograms recorded on a particular instrument, the Wood-Anderson torsion seismometer. ![]() The effective limit of measurement for local magnitude is about M L = 6.8 ) in the energy released. So, for example, an earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a Wood–Anderson torsion seismometer output. This scale is more useful in a sense that it provides some insight into the fault plane geometry of the earthquake based on parameter $M_0$.The Richter magnitude scale, or more correctly local magnitude M L scale, assigns a single number to quantify the amount of seismic energy released by an earthquake. The magnitude( $M_0$) is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of the area that slipped. Where $M_0$ is the seismic moment in N⋅m ( $10^7$ dyne⋅cm). The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs (adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake). ![]() The problem with most scales is that they become saturated after a certain magnitude.ģ scales can be named which fall in this category An earthquake measured to 9.0 is one million times stronger than an earthquake at 5.0. A difference in magnitude of 2.0 is equivalent to a factor of 1000. Some of the confusion might come from that the Richter scale is logarithmic. There are few other scales, Body wave magnitude, surface wave magnitude, but to my knowledge they also stay under 10. Related to the Richter's scale is the Moment magnitude scale, it's an updated better way to measure, but it usually produce similar values as the old Richter's scale and the two scales are often confused in media. Magnitude is also measured in different scales. Medvedev–Sponheuer–Karnik scale is used in some Asian and European countries, Russia, India, Israel etc. XII on the Medvedev–Sponheuer–Karnik scale is Very catastrophic and IX in Destructive. ![]() China seismic intensity scale (CSIS), Medvedev–Sponheuer–Karnik scale and European macroseismic scale can reach values above ten, but not 13-14. Modified Mercalli Intensity scale is a way to rate the intensity of an earthquake, but the scale ends at XII (Damage total), not at 13-14 (XIII-XIV), as mentioned. Naturally an earthquake with high magnitude would also generate high intensity, but the intensity depends on distance from the hypocenter and the local geological conditions. Intensity is determined from effects on buildings, landscape and people. Magnitude is the energy released of the earthquake. ![]() Magnitude and intensity are related but measure very different properties of the event. Earthquakes are measured for intensity and magnitude.
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