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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]
As the energy of a wave is proportional to A 1.5, where A denotes the amplitude, each unit of magnitude represents a 10 1.5 ≈ 32-fold increase in the seismic energy (strength) of an earthquake. [13] Second, Richter arbitrarily defined the zero point of the scale to be where an earthquake at a distance of 100 km makes a maximum horizontal ...
That is, many low-magnitude earthquakes are not catalogued because fewer stations detect and record them due to decreasing instrumental signal to noise levels. Some modern models of earthquake dynamics, however, predict a physical roll-off in the earthquake size distribution. [13] The a-value represents the total seismicity rate of the region ...
A major earthquake measuring 7.4 hit Taiwan early Wednesday, killing 9 and injuring at least 1,000. A 7.4 earthquake is exponentially more destructive than the 4.8 quake that struck central New ...
Where an earthquake is not recorded on seismographs an isoseismal map showing the intensities felt at different areas can be used to estimate the location and magnitude of the quake. [1] Such maps are also useful for estimating the shaking intensity, and thereby the likely level of damage, to be expected from a future earthquake of similar ...
This scale is also known as the Richter scale, but news media sometimes use that term indiscriminately to refer to other similar scales.) The local magnitude scale was developed on the basis of shallow (~15 km (9 mi) deep), moderate-sized earthquakes at a distance of approximately 100 to 600 km (62 to 373 mi), conditions where the surface waves ...
The first, six-level intensity scale was proposed by Egen in 1828 for an earthquake in Rhineland. [4] [5] Robert Mallet coined the term "isoseismal" and produced a map for the 1857 Basilicata earthquake with a three-fold intensity scale and used this and other information to identify the epicentral area (a term he also coined). [6]
Unlike the Richter and moment magnitude scales, it is not a measure of the total energy (magnitude, or size) of an earthquake, but rather of how much the earth shakes at a given geographic point. The Mercalli intensity scale uses personal reports and observations to measure earthquake intensity but PGA is measured by instruments, such as ...