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The JMA scale is expressed in levels of seismic intensity from 0 to 7 in a manner similar to that of the Mercalli intensity scale, which is not commonly used in Japan.The JMA uses seismic intensity meters to automatically calculate peak ground acceleration in real-time, reporting intensities based on measurements from observation points.
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 ...
Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake. They are distinguished from seismic magnitude scales , which measure the magnitude or overall strength of an earthquake, which may, or perhaps may not, cause perceptible shaking.
Scientists recorded a slow-slip event in 2011 before the magnitude-9 Tohoku earthquake and tsunami in Japan, which killed more than 18,000 people and touched off the Fukushima nuclear disaster.
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 ...
A seismogram recorded in Massachusetts, United States. The magnitude 9.1 (M w) undersea megathrust earthquake occurred on 11 March 2011 at 14:46 JST (05:46 UTC) in the north-western Pacific Ocean at a relatively shallow depth of 32 km (20 mi), [9] [56] with its epicenter approximately 72 km (45 mi) east of the Oshika Peninsula of Tōhoku, Japan, lasting approximately six minutes.
In Japan, the Shindo scale is commonly used to measure earthquakes by seismic intensity instead of magnitude. This is similar to the Modified Mercalli intensity scale used in the United States or the Liedu scale used in China, meaning that the scale measures the intensity of an earthquake at a given location instead of measuring the energy an earthquake releases at its epicenter (its magnitude ...