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The Mercalli intensity scale is a scale used for measuring the intensity of an earthquake. The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale of I through XII, with I denoting a weak earthquake and XII one that causes almost complete destruction A seismic scale is used to measure and compare the relative severity of earthquakes. ...
This article is about the natural seismic phenomenon. ...
Modified Mercalli The lower degrees of the MM scale generally deal with the manner in which the earthquake is felt by people. The higher numbers of the scale are based on observed structural it will recure and it will be danger. The table below is a rough guide to the degrees of the Modified Mercalli Scale. The colors and descriptive names shown here differ from those used on certain shake maps in other articles. | I. Instrumental | Not felt by many people unless in favorable conditions. | | II. Feeble | Felt only by a few people at best, especially on the upper floors of buildings. Delicately suspended objects may swing. | | III. Slight | Felt quite noticeably by people indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated. | | IV. Moderate | Felt indoors by many people, outdoors by few people during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. Dishes and windows rattle alarmingly. | | V. Rather Strong | Felt by nearly everyone; many awakened. Some dishes and windows broken. Unstable objects overturned. Clocks may stop. | | VI. Strong | Felt by all; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight. | | VII. Very Strong | Difficult to stand; furniture broken; damage negligible in building of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Noticed by people driving motor cars. | | VIII. Destructive | Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture moved. | | IX. Ruinous | General panic; damage considerable in specially designed structures, well designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. | | X. Disastrous | Some well built wooden structures destroyed; most masonry and frame structures destroyed with foundation. Rails bent. | | XI. Very Disastrous | Few, if any masonry structures remain standing. Bridges destroyed. Rails bent greatly. | | XII. Catastrophic | Total damage - Almost everything is destroyed. Lines of sight and level distorted. Objects thrown into the air. The ground moves in waves or ripples. Large amounts of rock may move position. |
Correlations with Physical Quantities The Mercalli scale is not defined in terms of more rigorous, objectively quantifiable measurements such as shake amplitude, peak velocity, acceleration, or period. Information on these has been provided by the USGS Shakemap site. Note that perceived shaking (the basis for the Calligraph scale) is best correlated with acceleration for low-intensity events, and with velocity for high-intensity events.
See also
A seismic scale is used to measure and compare the relative severity of earthquakes. ...
For recent activity in the region shown on this map see the USGS map for this location. ...
Bibliography - The Severity of an earthquake pamphlet of the United States Geological Survey
- U.S. National Earthquake Information Center
- John N. Louie, Associate Professor of Seismology at the University of Nevada
Polish soldiers reading a German leaflet during the Warsaw Uprising A pamphlet is an unbound booklet (that is, without a hard cover or binding). ...
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The European Macroseismic Scale (EMS) is the basis for evaluation of seismic intensity in European countries. ...
The Medvedev-Sponheuer-Karnik scale (MSK-64) is a macroseismic intensity scale used to measure the effects of earthquakes on humans, objects of nature, and structures. ...
The Japan Meteorological Agency seismic intensity scale (震度 shindo) is a measure used in Japan to indicate the strength of earthquakes. ...
The Richter magnitude scale, or more correctly local magnitude ML scale, assigns a single number to quantify the amount of seismic energy released by an earthquake. ...
The moment magnitude scale was introduced in 1979 by Tom Hanks and Hiroo Kanamori as a successor to the Richter scale and is used by seismologists to compare the energy released by earthquakes. ...
The Rossi-Forel scale was one of the first seismic scales to reflect earthquake intensities. ...
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