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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]
Much of an earthquake's total energy as measured by M w is dissipated as friction (resulting in heating of the crust). [52] An earthquake's potential to cause strong ground shaking depends on the comparatively small fraction of energy radiated as seismic waves, and is better measured on the energy magnitude scale, M e. [53]
Seismic observations in Japan began in 1872. In 1884, Sekiya Seikei, Director of the Earthquake Division under the Home Ministry, compiled the 18-article "Earthquake Report Guidelines" and initiated data collection from 600 county offices nationwide. This was Japan’s first unified seismic intensity scale.
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 ...
This meant that giant earthquakes such as the 1960 Chilean earthquake (M 9.5) were only assigned an M s 8.2. Caltech seismologist Hiroo Kanamori [ 47 ] recognized this deficiency and took the simple but important step of defining a magnitude based on estimates of radiated energy, M w , where the "w" stood for work (energy):
The 1980 Livermore earthquake occurred on January 24 at 11:00 PST in California. The epicenter of the 5.8 M w earthquake was a hilly area 12 km (7.5 mi) southeast of Mount Diablo and north of Livermore Valley. The earthquake had a maximum Modified Mercalli intensity of VII (Very strong).
Reflections and refractions of seismic waves at geologic interfaces within the Earth were first observed on recordings of earthquake-generated seismic waves. The basic model of the Earth's deep interior is based on observations of earthquake-generated seismic waves transmitted through the Earth's interior (e.g., Mohorovičić, 1910). [ 1 ]
Seismology (/ s aɪ z ˈ m ɒ l ə dʒ i, s aɪ s-/; from Ancient Greek σεισμός (seismós) meaning "earthquake" and -λογία (-logía) meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic waves through planetary bodies.