Seismic Intensity - Revision history

Maechlin at 22:26, 15 September 2017

2017-09-15T22:26:25Z

Maechlin at 20:12, 24 August 2014

2014-08-24T20:12:38Z

Maechlin at 22:28, 31 July 2014

2014-07-31T22:28:10Z

Maechlin at 19:45, 30 July 2014

2014-07-30T19:45:45Z

Maechlin: /* Intensity */

2014-07-29T23:01:12Z

Intensity

Maechlin at 22:59, 29 July 2014

2014-07-29T22:59:21Z

Maechlin at 22:59, 29 July 2014

2014-07-29T22:59:11Z

Maechlin at 16:05, 29 July 2014

2014-07-29T16:05:36Z

Maechlin: Created page with 'The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magni…'

2014-07-29T15:58:44Z

Created page with 'The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magni…'

New page

The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake (sometimes misreported as the Richter magnitude), which is a measure of the energy released. The intensity of an earthquake is not totally determined by its magnitude.

The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale from I (not felt) to XII (total destruction).[1][2] Values depend upon the distance to the earthquake, with the highest intensities being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location. The Mercalli (Intensity) scale originated with the widely used simple ten-degree Rossi-Forel scale which was revised by Italian volcanologist, Giuseppe Mercalli in 1884 and 1906.

== Related Entries ==
*[http://en.wikipedia.org/wiki/Mercalli_intensity_scale Wikipedia on MMI Scale]
*[USGS ShakeMap]
*[[CyberShake Project]]

← Older revision		Revision as of 22:26, 15 September 2017
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	There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.		There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.
		+
		+	== Intensity Description ==
		+
		+	A day after the quake, the editors of The New York Times sought to allay readers’ fear. The quake, they said, was an unexpected fluke never to be repeated and not worth anyone’s attention: “History and the researches of scientific men indicate that great seismic disturbances occur only within geographical limits that are now well defined,” they wrote in an editorial. “The northeastern portion of the United States . . . is not within those limits.” The editors then went on to scoff at the histrionics displayed by New York residents when confronted by the quake: “They do not stop to reason or to recall the fact that earthquakes here are harmless phenomena. They only know that the solid earth, to whose immovability they have always turned with confidence when everything else seemed transitory, uncertain, and deceptive, is trembling and in motion, and the tremor ceases long before their disturbed minds become tranquil.”
		+

	== Visual Examples ==		== Visual Examples ==

@@ Line 17: / Line 17: @@
 *[http://quake.abag.ca.gov/shaking/mmi/ Earthquake Hazards Program MMI Information]
 *[http://earthquake.usgs.gov/research/shakemap USGS ShakeMap]
-*[http://intensitylab.com ShakeMap California Earthquake Intensity Reports]
+*[http://www.intensitylab.com California Earthquake Intensity Reports]
 *[[CyberShake Project]]

← Older revision		Revision as of 22:28, 31 July 2014
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	There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.		There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.
		+
		+	== Visual Examples ==
		+	Richard Allen's Berkeley group has assembled a set of images and movies illustrating various MMI levels.
		+
		+	*[https://www.youtube.com/playlist?list=PLaLpP50ifUEgQP6KxYceJeEjQ0ePDQeuN UCB MMI Examples (Movies)]

	== Related Entries ==		== Related Entries ==

@@ Line 12: / Line 12: @@
 *[http://quake.abag.ca.gov/shaking/mmi/ Earthquake Hazards Program MMI Information]
 *[http://earthquake.usgs.gov/research/shakemap USGS ShakeMap]
 *[[CyberShake Project]]

@@ Line 4: / Line 4: @@
 == Intensity ==
-Before instruments for measuring earthquakes were developed, scientists observed that the amount of shaking felt by people and amount of damage to structures depended on their location. For big earthquakes in which the ground ruptured, the strongest shaking and the most damage were observed close to the rupture. In many smaller earthquakes, the ground did not rupture, but the strongest shaking and damage were still concentrated. Scientists developed a scale to quantify an earthquake's shaking by what was felt and by its effects on structures and the landscape. The most widely used scale is the Modified Mercalli Intensity Scale (MMI scale). It was originally introduced by the Italian seismologist Giuseppe Mercalli in 1902, and was modified and updated for “modern” building practices in 1931. It has twelve levels describing the strength of shaking.
+Before instruments for measuring earthquakes were developed, scientists observed that the amount of shaking felt by people and amount of damage to structures depended on their location. For big earthquakes in which the ground ruptured, the strongest shaking and the most damage were observed close to the rupture. In many smaller earthquakes, the ground did not rupture, but the strongest shaking and damage were still concentrated. Scientists developed a scale to quantify an earthquake's shaking by what was felt and by its effects on structures and the landscape. The most widely used scale is the Modified Mercalli Intensity Scale (MMI scale).
 There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.

@@ Line 3: / Line 3: @@
 The seismic scale most commonly used in the United States is the Mercalli Intensity scale (MMI). MMI quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures. The USGS version of the MMI scale ranges from I (not felt) to X+ (very violent shaking).  Values depend upon the distance to the earthquake, with the highest intensities often being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location.
-== Intensity ===
+== Intensity ==
 Before instruments for measuring earthquakes were developed, scientists observed that the amount of shaking felt by people and amount of damage to structures depended on their location. For big earthquakes in which the ground ruptured, the strongest shaking and the most damage were observed close to the rupture. In many smaller earthquakes, the ground did not rupture, but the strongest shaking and damage were still concentrated. Scientists developed a scale to quantify an earthquake's shaking by what was felt and by its effects on structures and the landscape. The most widely used scale is the Modified Mercalli Intensity Scale (MMI scale). It was originally introduced by the Italian seismologist Giuseppe Mercalli in 1902, and was modified and updated for “modern” building practices in 1931. It has twelve levels describing the strength of shaking.

← Older revision		Revision as of 22:59, 29 July 2014
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	The seismic scale most commonly used in the United States is the Mercalli Intensity scale (MMI). MMI quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures. The USGS version of the MMI scale ranges from I (not felt) to X+ (very violent shaking). Values depend upon the distance to the earthquake, with the highest intensities often being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location.		The seismic scale most commonly used in the United States is the Mercalli Intensity scale (MMI). MMI quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures. The USGS version of the MMI scale ranges from I (not felt) to X+ (very violent shaking). Values depend upon the distance to the earthquake, with the highest intensities often being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location.
		+
		+	== Intensity ===
		+	Before instruments for measuring earthquakes were developed, scientists observed that the amount of shaking felt by people and amount of damage to structures depended on their location. For big earthquakes in which the ground ruptured, the strongest shaking and the most damage were observed close to the rupture. In many smaller earthquakes, the ground did not rupture, but the strongest shaking and damage were still concentrated. Scientists developed a scale to quantify an earthquake's shaking by what was felt and by its effects on structures and the landscape. The most widely used scale is the Modified Mercalli Intensity Scale (MMI scale). It was originally introduced by the Italian seismologist Giuseppe Mercalli in 1902, and was modified and updated for “modern” building practices in 1931. It has twelve levels describing the strength of shaking.
		+
		+	There are two basic differences between the intensity of an earthquake and its magnitude. The magnitude of an earthquake is based on measurements from instruments, so it is objective. Intensity is a subjective measure. It is based on the observations and descriptions of people, those living in the area where the earthquake occurred and also the engineers or scientists estimating the damage to structures. The second difference is that an earthquake has only one magnitude, while its intensity will be different at the different locations. A single earthquake will usually generate a whole range of intensities. The values generally decrease as the distance from the epicenter increases.

	== Related Entries ==		== Related Entries ==

@@ Line 1: / Line 1: @@
-The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake (sometimes misreported as the Richter magnitude), which is a measure of the energy released. The intensity of an earthquake is not totally determined by its magnitude.
+Seismic intensity scales are used to measure the intensity of an earthquake. A seismic intensity scale measures the effects of an earthquake, and is distinct from earthquake magnitude scales, usually reported for an earthquake in the United States. Earthquake Magnitude scales can be thought of as a measure of the total energy released by the earthquake. The intensity of an earthquake varies by sites, and is not totally determined by its magnitude.
-The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale from I (not felt) to XII (total destruction).[1][2] Values depend upon the distance to the earthquake, with the highest intensities being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location. The Mercalli (Intensity) scale originated with the widely used simple ten-degree Rossi-Forel scale which was revised by Italian volcanologist, Giuseppe Mercalli in 1884 and 1906.
+The seismic scale most commonly used in the United States is the Mercalli Intensity scale (MMI). MMI quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures. The USGS version of the MMI scale ranges from I (not felt) to X+ (very violent shaking).  Values depend upon the distance to the earthquake, with the highest intensities often being around the epicentral area. Data gathered from people who have experienced the quake are used to determine an intensity value for their location.
 == Related Entries ==
 *[http://en.wikipedia.org/wiki/Mercalli_intensity_scale Wikipedia on MMI Scale]
-*[USGS ShakeMap]
+*[http://quake.abag.ca.gov/shaking/mmi/ Earthquake Hazards Program MMI Information]
 *[[CyberShake Project]]