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The moment magnitude scale ... (Log W 0 = 1.5 M w + 11.8, where W 0 is the minimum strain energy) for great earthquakes using Gutenberg Richter Eq. (1).
The Richter scale [1] (/ ˈ r ɪ k t ər /), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, [2] is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and presented in Richter's landmark 1935 paper, where he called it the "magnitude scale". [3]
Officially it's called the moment magnitude scale. It's a logarithmic scale , meaning each number is 10 times as strong as the one before it. So a 5.0 earthquake is ten times stronger than a 4.0.
An earthquake's seismic moment can be estimated in various ways, which are the bases of the M wb, M wr, M wc, M ww, M wp, M i, and M wpd scales, all subtypes of the generic M w scale. See Moment magnitude scale § Subtypes for details. Seismic moment is considered the most objective measure of an earthquake's "size" in regard of total energy. [50]
The JMA intensity scale differs from magnitude measurements like the moment magnitude (Mw) and the earlier Richter scales, which represent how much energy an earthquake releases. Similar to the Mercalli scale , the JMA scale measures the intensities of ground shaking at various observation points within the affected area .
Although the mass media commonly reports earthquake magnitudes as "Richter magnitude" or "Richter scale", standard practice by most seismological authorities is to express an earthquake's strength on the moment magnitude scale, which is based on the actual energy released by an earthquake, the static seismic moment. [59] [60]
The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or strength of an earthquake – an event occurring at greater or lesser depth. (The "M w" scale is ...
Seismic moment is the basis of the moment magnitude scale introduced by Caltech's Thomas C. Hanks and Hiroo Kanamori, which is often used to compare the size of different earthquakes and is especially useful for comparing the sizes of large (great) earthquakes. The seismic moment is not restricted to earthquakes. For a more general seismic ...