|
|
|
|
Mercalli intensity scale
|
| |
|
| |
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.
The Mercalli scale is based on the amount of resulting physical damage received and the data is gathered from individuals who have experienced the quake.
Mercalli scale originated with the widely used simple ten-degree Rossi-Forel scale, which was revised by Italian volcanologist Giuseppe Mercalli in 1883 and 1902.
Discussion
Ask a question about 'Mercalli intensity scale' Start a new discussion about 'Mercalli intensity scale' Answer questions from other users |
Encyclopedia
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.
The Mercalli scale is based on the amount of resulting physical damage received and the data is gathered from individuals who have experienced the quake.
Evolution of the Mercalli scale
The Mercalli scale originated with the widely used simple ten-degree Rossi-Forel scale, which was revised by Italian volcanologist Giuseppe Mercalli in 1883 and 1902. The terms or Mercalli scale should not be used unless one really means the original ten-degree scale of 1902.
In 1902 the ten-degree Mercalli scale was expanded to twelve degrees by Italian physicist Adolfo Cancani. It was later completely re-written by German geophysicist August Heinrich Sieberg and became known as the Mercalli-Cancani-Sieberg (MCS) scale. The Mercalli-Cancani-Sieberg scale was later modified and published in English by Harry O. Wood and Frank Neumann in 1931 as the Mercalli-Wood-Neuman (MWN) scale. It was later improved by Charles Richter, the father of the Richter magnitude scale. The scale is known today as the Modified Mercalli Scale and commonly abbreviated MM.
Modified Mercalli scale
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 damage. 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.
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 . 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
Bibliography
|
| |
|
|
