Search results
Results from the WOW.Com Content Network
Magnitude is an estimate of the relative "size" or strength of an earthquake, and thus its potential for causing ground-shaking. It is "approximately related to the released seismic energy". [1] Intensity refers to the strength or force of shaking at a given location, and can be related
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.
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]
For example, a magnitude 7.0 quake in Salta, Argentina, in 2011, that was 576.8 km deep, had a maximum felt intensity of V, [19] while a magnitude 2.2 event in Barrow in Furness, England, in 1865, about 1 km deep, had a maximum felt intensity of VIII. [20] The small table is a rough guide to the degrees of the MMI scale.
Intensity data is collected from 4,300 observation stations equipped with "Model 95" accelerometers that measure strong ground motion [3] [4]. The agency provides the public with real-time reports through the media and Internet [5] giving event time, epicenter (location), magnitude, and depth followed by intensity readings at affected localities.
The difference between these concepts can be seen by comparing two stars. Betelgeuse (apparent magnitude 0.5, absolute magnitude −5.8) appears slightly dimmer in the sky than Alpha Centauri A (apparent magnitude 0.0, absolute magnitude 4.4) even though it emits thousands of times more light, because Betelgeuse is much farther away.
In physics and many other areas of science and engineering the intensity or flux of radiant energy is the power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy.
Thus, a magnitude zero microearthquake has a seismic moment of approximately 1.1 × 10 9 N⋅m, while the Great Chilean earthquake of 1960, with an estimated moment magnitude of 9.4–9.6, had a seismic moment between 1.4 × 10 23 N⋅m and 2.8 × 10 23 N⋅m. Seismic moment magnitude (M wg or Das Magnitude Scale ) and moment magnitude (M w) scales