The modified Mercalli intensity scale (MM,MMI or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used to measure the intensity of shaking produced by an earthquake. It measures the effects of an earthquake at a given location, distinguished from the inherent force or force of the earthquake as measured by seismic magnitude scales (such as the "M" magnitude usually reported for an earthquake). While shaking is caused by seismic energy released by an earthquake, earthquakes differ in how much of their energy is radiated as seismic waves. Deeper earthquakes also have less interaction with the surface, and their energy is distributed across a larger volume. The intensity of the shaking is localized, generally decreasing with distance from the earthquake epicenter, but can be amplified in sedimentary basins and certain types of unconsolidated soils.
Intensity scales empirically classify shaking intensity based on effects reported by untrained observers and are tailored to effects that might be observed in a particular region.[1] By not requiring instrumental measurements, they are useful for estimating the magnitude and location of historical (pre-instrumental) earthquakes: the highest intensities generally correspond to the epicentral area, and their degree and extent (possibly augmented by knowledge of local geological conditions) can be compared with other local earthquakes to estimate the magnitude.
History
The Italian volcanologist Giuseppe Mercalli formulated his first intensity scale in 1883. It had six degrees or categories, it has been described as "a mere adaptation" of the 10-degree Rossi-Forel scale, which was the standard at the time, and is now "more or less forgotten." Mercalli's second scale, published in 1902, was also an adaptation of the Rossi-Forel scale, retaining the 10 degrees and expanding the descriptions of each degree.[4] This version “pleased the users” and was adopted by the Italian Central Office of Meteorology and Geodynamics.[5].
In 1904, Adolfo Cancani proposed adding two additional degrees for very strong earthquakes, "catastrophe" and "enormous catastrophe", thus creating a 12-degree scale.[6] Their descriptions were poor, so August Heinrich Sieberg expanded them between 1912 and 1923, and indicated a maximum ground acceleration for each degree.[7] This scale became known as the "Mercalli-Cancani scale, formulated by Sieberg", or the "Mercalli-Cancani-Sieberg scale", or simply "MCS",[8] and was widely used in Europe and continues to be used in Italy by the National Institute of Geophysics and Volcanology (INGV).[9].
Review of partial collapses
Introduction
The modified Mercalli intensity scale (MM,MMI or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used to measure the intensity of shaking produced by an earthquake. It measures the effects of an earthquake at a given location, distinguished from the inherent force or force of the earthquake as measured by seismic magnitude scales (such as the "M" magnitude usually reported for an earthquake). While shaking is caused by seismic energy released by an earthquake, earthquakes differ in how much of their energy is radiated as seismic waves. Deeper earthquakes also have less interaction with the surface, and their energy is distributed across a larger volume. The intensity of the shaking is localized, generally decreasing with distance from the earthquake epicenter, but can be amplified in sedimentary basins and certain types of unconsolidated soils.
Intensity scales empirically classify shaking intensity based on effects reported by untrained observers and are tailored to effects that might be observed in a particular region.[1] By not requiring instrumental measurements, they are useful for estimating the magnitude and location of historical (pre-instrumental) earthquakes: the highest intensities generally correspond to the epicentral area, and their degree and extent (possibly augmented by knowledge of local geological conditions) can be compared with other local earthquakes to estimate the magnitude.
History
The Italian volcanologist Giuseppe Mercalli formulated his first intensity scale in 1883. It had six degrees or categories, it has been described as "a mere adaptation" of the 10-degree Rossi-Forel scale, which was the standard at the time, and is now "more or less forgotten." Mercalli's second scale, published in 1902, was also an adaptation of the Rossi-Forel scale, retaining the 10 degrees and expanding the descriptions of each degree.[4] This version “pleased the users” and was adopted by the Italian Central Office of Meteorology and Geodynamics.[5].
When Harry O. Wood and Frank Neumann translated this into English in 1931 (along with modifying and condensing the descriptions, and eliminating the acceleration criterion), they called it the "modified Mercalli intensity scale of 1931" (MM31). Some seismologists refer to this version as the "Wood-Neumann scale." of intensity.
The Wood-Neumann scale was revised in 1956 by Charles Francis Richter and published in his influential textbook Elementary Seismology.[11] To prevent this intensity scale from being confused with the Richter scale that he himself had developed, he proposed calling it the "modified Mercalli scale of 1956" (MM56).[8]
In their 1993 compendium of historical seismicity in the United States,[12] Carl Stover") and Jerry Coffman") ignored Richter's revision and assigned intensities based on their slightly modified interpretation of the 1931 Wood and Neumann scale,[13] thus creating a new, albeit largely undocumented, version of the scale.[14]
The basis on which the United States Geological Survey (USGS) and other agencies assign intensities is, in theory, the MM31 scale of Wood and Neumann. However, this is generally interpreted with the modifications summarized by Stover and Coffman, since, in the decades since 1931, "some criteria are more reliable than others as indicators of the level of ground shaking." In addition, construction codes and methods have evolved, which has strengthened much of the built environment; this makes a given intensity of ground shaking appear weaker. Furthermore, some of the original criteria for the more intense grades (X and above), such as bent rails, ground cracks, landslides, etc., "are less related to the level of ground shaking than to the presence of ground conditions susceptible to spectacular failures."[15]
The “catastrophe” and “massive catastrophe” categories added by Cancani (XI and
Modified Mercalli Scale
Contenido
Los niveles bajos de la escala están asociados por la forma en que las personas sienten el movimiento, mientras que los grados más altos se relacionan con el daño estructural observado. La tabla siguiente es una guía aproximada de los grados de la escala de Mercalli modificada.[17][18].
[11] ↑ Richter, 1958; Musson, Grünthal y Stucchi, 2010, p. 416.
[12] ↑ Stover y Coffman, 1993.
[13] ↑ Sus modificaciones se referían principalmente a los grados IV y V, con el VI supeditado a los informes de daños en estructuras artificiales, y el VII considerando únicamente «daños en edificios u otras estructuras artificiales». Véanse los detalles en Stover y Coffman, 1993, pp. 3–4.
[14] ↑ Grünthal, 2011, p. 238. La exposición más definitiva de la escala efectiva de Stover y Coffman se encuentra en Musson y Cecić, 2012, §12.2.2.
[19] ↑ a b c d e f g h i j k l INSIVUMEH. «Escala de Mercalli Modificada (M.M.)». Consultado el 25 de mayo de 2011. - [http://www.insivumeh.gob.gt/geofisica/indice%20sismo.htm#ESCALA%20DE%20MERCALLI%20MODIFICADA%20(M.%20M.)](http://www.insivumeh.gob.gt/geofisica/indice%20sismo.htm#ESCALA%20DE%20MERCALLI%20MODIFICADA%20(M.%20M.))
In 1904, Adolfo Cancani proposed adding two additional degrees for very strong earthquakes, "catastrophe" and "enormous catastrophe", thus creating a 12-degree scale.[6] Their descriptions were poor, so August Heinrich Sieberg expanded them between 1912 and 1923, and indicated a maximum ground acceleration for each degree.[7] This scale became known as the "Mercalli-Cancani scale, formulated by Sieberg", or the "Mercalli-Cancani-Sieberg scale", or simply "MCS",[8] and was widely used in Europe and continues to be used in Italy by the National Institute of Geophysics and Volcanology (INGV).[9].
When Harry O. Wood and Frank Neumann translated this into English in 1931 (along with modifying and condensing the descriptions, and eliminating the acceleration criterion), they called it the "modified Mercalli intensity scale of 1931" (MM31). Some seismologists refer to this version as the "Wood-Neumann scale." of intensity.
The Wood-Neumann scale was revised in 1956 by Charles Francis Richter and published in his influential textbook Elementary Seismology.[11] To prevent this intensity scale from being confused with the Richter scale that he himself had developed, he proposed calling it the "modified Mercalli scale of 1956" (MM56).[8]
In their 1993 compendium of historical seismicity in the United States,[12] Carl Stover") and Jerry Coffman") ignored Richter's revision and assigned intensities based on their slightly modified interpretation of the 1931 Wood and Neumann scale,[13] thus creating a new, albeit largely undocumented, version of the scale.[14]
The basis on which the United States Geological Survey (USGS) and other agencies assign intensities is, in theory, the MM31 scale of Wood and Neumann. However, this is generally interpreted with the modifications summarized by Stover and Coffman, since, in the decades since 1931, "some criteria are more reliable than others as indicators of the level of ground shaking." In addition, construction codes and methods have evolved, which has strengthened much of the built environment; this makes a given intensity of ground shaking appear weaker. Furthermore, some of the original criteria for the more intense grades (X and above), such as bent rails, ground cracks, landslides, etc., "are less related to the level of ground shaking than to the presence of ground conditions susceptible to spectacular failures."[15]
The “catastrophe” and “massive catastrophe” categories added by Cancani (XI and
Modified Mercalli Scale
Contenido
Los niveles bajos de la escala están asociados por la forma en que las personas sienten el movimiento, mientras que los grados más altos se relacionan con el daño estructural observado. La tabla siguiente es una guía aproximada de los grados de la escala de Mercalli modificada.[17][18].
[11] ↑ Richter, 1958; Musson, Grünthal y Stucchi, 2010, p. 416.
[12] ↑ Stover y Coffman, 1993.
[13] ↑ Sus modificaciones se referían principalmente a los grados IV y V, con el VI supeditado a los informes de daños en estructuras artificiales, y el VII considerando únicamente «daños en edificios u otras estructuras artificiales». Véanse los detalles en Stover y Coffman, 1993, pp. 3–4.
[14] ↑ Grünthal, 2011, p. 238. La exposición más definitiva de la escala efectiva de Stover y Coffman se encuentra en Musson y Cecić, 2012, §12.2.2.
[19] ↑ a b c d e f g h i j k l INSIVUMEH. «Escala de Mercalli Modificada (M.M.)». Consultado el 25 de mayo de 2011. - [http://www.insivumeh.gob.gt/geofisica/indice%20sismo.htm#ESCALA%20DE%20MERCALLI%20MODIFICADA%20(M.%20M.)](http://www.insivumeh.gob.gt/geofisica/indice%20sismo.htm#ESCALA%20DE%20MERCALLI%20MODIFICADA%20(M.%20M.))