{"id":2023,"date":"2016-06-03T19:48:16","date_gmt":"2016-06-03T19:48:16","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/geologyxwaymakerxmaster\/?post_type=chapter&#038;p=2023"},"modified":"2023-06-28T01:03:52","modified_gmt":"2023-06-28T01:03:52","slug":"outcome-magnitude-and-intensity","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/chapter\/outcome-magnitude-and-intensity\/","title":{"raw":"Magnitude and Intensity","rendered":"Magnitude and Intensity"},"content":{"raw":"<h2>Define and compare magnitude versus intensity<\/h2>\r\nThis section introduces you to the magnitude and intensity of earthquakes. You will learn how the two are similar and how they are different.\r\n<div class=\"textbox learning-objectives\">\r\n<h3>What You\u2019ll Learn to Do<\/h3>\r\n<ul>\r\n \t<li>Define earthquake magnitude.<\/li>\r\n \t<li>Define earthquake intensity.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>Measuring Earthquakes<\/h2>\r\nPeople have always tried to quantify the size of and damage done by earthquakes. Since early in the 20th century, there have been three methods. What are the strengths and weaknesses of each?\r\n<ul>\r\n \t<li>Mercalli Intensity Scale. Earthquakes are described in terms of what nearby residents felt and the damage that was done to nearby structures.<\/li>\r\n \t<li>Richter magnitude scale. Developed in 1935 by Charles Richter, this scale uses a seismometer to measure the magnitude of the largest jolt of energy released by an earthquake.<\/li>\r\n \t<li>Moment magnitude scale. Measures the total energy released by an earthquake. Moment magnitude is calculated from the area of the fault that is ruptured and the distance the ground moved along the fault.<\/li>\r\n<\/ul>\r\nThe Richter scale and the moment magnitude scale are logarithmic.\r\n<ul>\r\n \t<li>The amplitude of the largest wave increases ten times from one integer to the next.<\/li>\r\n \t<li>An increase in one integer means that thirty times more energy was released.<\/li>\r\n \t<li>These two scales often give very similar measurements.<\/li>\r\n<\/ul>\r\nHow does the amplitude of the largest seismic wave of a magnitude 5 earthquake compare with the largest wave of a magnitude 4 earthquake? How does it compare with a magnitude 3 quake? The amplitude of the largest seismic wave of a magnitude 5 quake is 10 times that of a magnitude 4 quake and 100 times that of a magnitude 3 quake.\r\n\r\nHow does an increase in two integers on the moment magnitude scale compare in terms of the amount of energy released? Two integers equals a 900-fold increase in released energy.\r\n\r\nWhich scale do you think is best? With the Richter scale, a single sharp jolt measures higher than a very long intense earthquake that releases more energy. The moment magnitude scale more accurately reflects the energy released and the damage caused. Most seismologists now use the moment magnitude scale.\r\n\r\nThe way scientists measure earthquake intensity and the two most common scales, Richter and moment magnitude, are described along with a discussion of the 1906 San Francisco earthquake in <em>Measuring Earthquakes<\/em> video:\r\n\r\n<script type=\"text\/javascript\" src=\"\/\/static.3playmedia.com\/p\/projects\/20361\/files\/1280980\/plugins\/11085.js\"><\/script><script src=\"https:\/\/www.youtube.com\/iframe_api\" type=\"text\/javascript\"><\/script>\r\n<iframe id=\"myytplayer\" src=\"https:\/\/www.youtube.com\/embed\/wtlu_aDteCA?enablejsapi=1\" width=\"440\" height=\"300\" frameborder=\"0\"><\/iframe>\r\n<h2>Magnitude versus\u00a0Intensity<\/h2>\r\nMagnitude and Intensity measure different characteristics of earthquakes. Magnitude measures the energy released at the source of the earthquake. <strong>Magnitude<\/strong> is determined from measurements on seismographs. <strong>Intensity<\/strong> measures the strength of shaking produced by the earthquake at a certain location. Intensity is determined from effects on people, human structures, and the natural environment.\r\n<h3>Calculating Earthquake Magnitude<\/h3>\r\nThe magnitude of an earthquake is a number that allows earthquakes to be compared with each other in terms of their relative power. For several decades, earthquake magnitudes were calculated based on a method first developed by Charles Richter, a seismologist based in California. Richter used seismograms of earthquakes that occurred in the San Andreas fault zone to calibrate his magnitude scale.\r\n\r\nTwo measurements are factored together to determine the Richter magnitude of an earthquake: the amplitude of the largest waves recorded on a seismogram of the earthquake, and the distance to the epicenter of the earthquake. The maximum amplitude seismic wave - the height of the tallest one - is measured in mm on a seismogram. The distance to the epicenter must also be taken into account because the greater the distance from the earthquake, the smaller the waves get. The effect of distance is factored out of the calculation. There is no upper limit defined for the Richter scale, but after a century of seismograph measurements, it appears that rocks in the earth release their stress before building up enough energy to reach magnitude 10.\r\n\r\nThe Richter scale was found to not transfer very well from the San Andreas fault zone, a transform plate boundary, to the much more powerful earthquakes that occur at convergent plate boundaries, particularly subduction zone earthquakes. Therefore, the Richter scale has been replaced by the moment magnitude scale, symbolized as <strong>M<sub>w<\/sub><\/strong>.\r\n\r\nThe moment magnitude scale is broadly similar to the Richter scale, but it takes more factors into account, including the total area of the fault that moves during the earthquake, and how much it moves. This produces a magnitude number that is a better indicator of the total amount of energy released by the earthquake. Because the moment magnitude scale has replaced the Richter scale, we will assume from here on that we are referring to moment magnitude, not Richter magnitude, when we speak of earthquake magnitude.\r\n\r\nThe magnitude scale portrays energy logarithmically to approximately base 32. For example, a magnitude 6.0 earthquake releases about 32 times as much energy as a magnitude 5.0 earthquake. A magnitude 7.0 releases about 32\u00a0\u00d7\u00a032\u00a0=\u00a01024 times as much energy as a magnitude 5.0 earthquake. A magnitude 9.0 earthquake, which rarely occurs, releases over a million times as much energy as a magnitude 5.0 earthquake.\r\n<h3>Ranking Earthquake Intensity<\/h3>\r\nEarthquake intensity is very different from earthquake magnitude. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place. Therefore, each earthquake produces a range of intensity values, ranging from highest in the epicenter area to zero at a distance from the epicenter. The most commonly used earthquake intensity scale is the Modified Mercalli earthquake intensity scale. Refer to the <a href=\"http:\/\/earthquake.usgs.gov\/learn\/topics\/mercalli.php\" target=\"_blank\" rel=\"noopener\">Modified Mercalli Intensity Scale<\/a> page on the US Geological Survey Earthquake Hazards Program website for an abbreviated version.\r\n\r\nThe table below shows approximately how many earthquakes occur each year in each magnitude range and what the intensity might be at the epicenter for each magnitude range.\r\n<table title=\"Earthquake Magnitude, Frequency and Intensity\" border=\"1\" width=\"75%\" cellpadding=\"5\">\r\n<tbody>\r\n<tr>\r\n<th width=\"10%\">Magnitude<\/th>\r\n<th width=\"10%\">Average number per year<\/th>\r\n<th width=\"10%\">Modified Mercalli Intensity<\/th>\r\n<th width=\"70%\">Description<\/th>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">0 - 1.9<\/td>\r\n<td align=\"center\">&gt;1 million<\/td>\r\n<td align=\"center\">--<\/td>\r\n<td>micro - not felt<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">2.0 - 2.9<\/td>\r\n<td align=\"center\">&gt;1 million<\/td>\r\n<td align=\"center\">I<\/td>\r\n<td>minor - rarely felt<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">3.0 - 3.9<\/td>\r\n<td align=\"center\">about 100,000<\/td>\r\n<td align=\"center\">II - III<\/td>\r\n<td>minor - noticed by a few people<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">4.0 - 4.9<\/td>\r\n<td align=\"center\">about 10,000<\/td>\r\n<td align=\"center\">IV - V<\/td>\r\n<td>light - felt by many people, minor damage possible<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">5.0 - 5.9<\/td>\r\n<td align=\"center\">about 1,000<\/td>\r\n<td align=\"center\">VI - VII<\/td>\r\n<td>moderate - felt by most people, possible broken plaster and chimneys<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">6.0 - 6.9<\/td>\r\n<td align=\"center\">about 130<\/td>\r\n<td align=\"center\">VII - IX<\/td>\r\n<td>strong - damage variable depending on building construction and substrate<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">7.0 - 7.9<\/td>\r\n<td align=\"center\">about 15<\/td>\r\n<td align=\"center\">IX - X<\/td>\r\n<td>major - extensive damage, some buildings destroyed<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">8.0 - 8.9<\/td>\r\n<td align=\"center\">about 1<\/td>\r\n<td align=\"center\">X - XII<\/td>\r\n<td>great - extensive damage over broad areas, many buildings destroyed<\/td>\r\n<\/tr>\r\n<tr>\r\n<td align=\"center\">9.0 and above<\/td>\r\n<td align=\"center\">&lt; 1<\/td>\r\n<td align=\"center\">XI - XII<\/td>\r\n<td>great - extensive damage over broad areas, most buildings destroyed<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<h3>Magnitude \/ Intensity Comparison<\/h3>\r\nThe following table gives intensities that are typically observed at locations near the epicenter of earthquakes of different magnitudes.\r\n<table class=\"tabular\">\r\n<tbody>\r\n<tr valign=\"top\">\r\n<th id=\"t1\">Magnitude<\/th>\r\n<th id=\"t2\">Typical Maximum\r\nModified Mercalli Intensity<\/th>\r\n<\/tr>\r\n<tr>\r\n<td headers=\"t1\"><b>1.0 - 3.0<\/b><\/td>\r\n<td headers=\"t2\"><b>I<\/b><\/td>\r\n<\/tr>\r\n<tr>\r\n<td headers=\"t1\"><b>3.0 - 3.9<\/b><\/td>\r\n<td headers=\"t2\"><b>II - III<\/b><\/td>\r\n<\/tr>\r\n<tr>\r\n<td headers=\"t1\"><b>4.0 - 4.9<\/b><\/td>\r\n<td headers=\"t2\"><b>IV - V<\/b><\/td>\r\n<\/tr>\r\n<tr>\r\n<td headers=\"t1\"><b>5.0 - 5.9<\/b><\/td>\r\n<td headers=\"t2\"><b>VI - VII<\/b><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><b>6.0 - 6.9<\/b><\/td>\r\n<td headers=\"t2\"><b>VII - IX<\/b><\/td>\r\n<\/tr>\r\n<tr>\r\n<td headers=\"t1\"><b>7.0<\/b> and higher<\/td>\r\n<td headers=\"t2\"><b>VIII<\/b> or higher<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<h3>Abbreviated Modified Mercalli Intensity Scale<\/h3>\r\n<ol>\r\n \t<li>Not felt except by a very few under especially favorable conditions.<\/li>\r\n \t<li>Felt only by a few persons at rest, especially on upper floors of buildings.<\/li>\r\n \t<li>Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.<\/li>\r\n \t<li>Felt indoors by many, outdoors by few 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.<\/li>\r\n \t<li>Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.<\/li>\r\n \t<li>Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.<\/li>\r\n \t<li>Damage negligible in buildings 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.<\/li>\r\n \t<li>Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.<\/li>\r\n \t<li>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.<\/li>\r\n \t<li>Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.<\/li>\r\n \t<li>Few, if any (masonry) structures remain standing. Bridges destroyed. Rails bent greatly.<\/li>\r\n \t<li>Damage total. Lines of sight and level are distorted. Objects thrown into the air.<\/li>\r\n<\/ol>\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Check Your Understanding<\/h3>\r\nThe Richter Scale measures what?\r\n<ul>\r\n \t<li>the total energy released by an earthquake<\/li>\r\n \t<li>the largest jolt of energy caused by an earthquake<\/li>\r\n \t<li>the damage caused by an earthquake<\/li>\r\n<\/ul>\r\n<details><summary>Show Answer<\/summary>the largest jolt of energy caused by an earthquake\r\n\r\n<\/details><\/div>\r\n","rendered":"<h2>Define and compare magnitude versus intensity<\/h2>\n<p>This section introduces you to the magnitude and intensity of earthquakes. You will learn how the two are similar and how they are different.<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>What You\u2019ll Learn to Do<\/h3>\n<ul>\n<li>Define earthquake magnitude.<\/li>\n<li>Define earthquake intensity.<\/li>\n<\/ul>\n<\/div>\n<h2>Measuring Earthquakes<\/h2>\n<p>People have always tried to quantify the size of and damage done by earthquakes. Since early in the 20th century, there have been three methods. What are the strengths and weaknesses of each?<\/p>\n<ul>\n<li>Mercalli Intensity Scale. Earthquakes are described in terms of what nearby residents felt and the damage that was done to nearby structures.<\/li>\n<li>Richter magnitude scale. Developed in 1935 by Charles Richter, this scale uses a seismometer to measure the magnitude of the largest jolt of energy released by an earthquake.<\/li>\n<li>Moment magnitude scale. Measures the total energy released by an earthquake. Moment magnitude is calculated from the area of the fault that is ruptured and the distance the ground moved along the fault.<\/li>\n<\/ul>\n<p>The Richter scale and the moment magnitude scale are logarithmic.<\/p>\n<ul>\n<li>The amplitude of the largest wave increases ten times from one integer to the next.<\/li>\n<li>An increase in one integer means that thirty times more energy was released.<\/li>\n<li>These two scales often give very similar measurements.<\/li>\n<\/ul>\n<p>How does the amplitude of the largest seismic wave of a magnitude 5 earthquake compare with the largest wave of a magnitude 4 earthquake? How does it compare with a magnitude 3 quake? The amplitude of the largest seismic wave of a magnitude 5 quake is 10 times that of a magnitude 4 quake and 100 times that of a magnitude 3 quake.<\/p>\n<p>How does an increase in two integers on the moment magnitude scale compare in terms of the amount of energy released? Two integers equals a 900-fold increase in released energy.<\/p>\n<p>Which scale do you think is best? With the Richter scale, a single sharp jolt measures higher than a very long intense earthquake that releases more energy. The moment magnitude scale more accurately reflects the energy released and the damage caused. Most seismologists now use the moment magnitude scale.<\/p>\n<p>The way scientists measure earthquake intensity and the two most common scales, Richter and moment magnitude, are described along with a discussion of the 1906 San Francisco earthquake in <em>Measuring Earthquakes<\/em> video:<\/p>\n<p><script type=\"text\/javascript\" src=\"\/\/static.3playmedia.com\/p\/projects\/20361\/files\/1280980\/plugins\/11085.js\"><\/script><script src=\"https:\/\/www.youtube.com\/iframe_api\" type=\"text\/javascript\"><\/script><br \/>\n<iframe loading=\"lazy\" id=\"myytplayer\" src=\"https:\/\/www.youtube.com\/embed\/wtlu_aDteCA?enablejsapi=1\" width=\"440\" height=\"300\" frameborder=\"0\"><\/iframe><\/p>\n<h2>Magnitude versus\u00a0Intensity<\/h2>\n<p>Magnitude and Intensity measure different characteristics of earthquakes. Magnitude measures the energy released at the source of the earthquake. <strong>Magnitude<\/strong> is determined from measurements on seismographs. <strong>Intensity<\/strong> measures the strength of shaking produced by the earthquake at a certain location. Intensity is determined from effects on people, human structures, and the natural environment.<\/p>\n<h3>Calculating Earthquake Magnitude<\/h3>\n<p>The magnitude of an earthquake is a number that allows earthquakes to be compared with each other in terms of their relative power. For several decades, earthquake magnitudes were calculated based on a method first developed by Charles Richter, a seismologist based in California. Richter used seismograms of earthquakes that occurred in the San Andreas fault zone to calibrate his magnitude scale.<\/p>\n<p>Two measurements are factored together to determine the Richter magnitude of an earthquake: the amplitude of the largest waves recorded on a seismogram of the earthquake, and the distance to the epicenter of the earthquake. The maximum amplitude seismic wave &#8211; the height of the tallest one &#8211; is measured in mm on a seismogram. The distance to the epicenter must also be taken into account because the greater the distance from the earthquake, the smaller the waves get. The effect of distance is factored out of the calculation. There is no upper limit defined for the Richter scale, but after a century of seismograph measurements, it appears that rocks in the earth release their stress before building up enough energy to reach magnitude 10.<\/p>\n<p>The Richter scale was found to not transfer very well from the San Andreas fault zone, a transform plate boundary, to the much more powerful earthquakes that occur at convergent plate boundaries, particularly subduction zone earthquakes. Therefore, the Richter scale has been replaced by the moment magnitude scale, symbolized as <strong>M<sub>w<\/sub><\/strong>.<\/p>\n<p>The moment magnitude scale is broadly similar to the Richter scale, but it takes more factors into account, including the total area of the fault that moves during the earthquake, and how much it moves. This produces a magnitude number that is a better indicator of the total amount of energy released by the earthquake. Because the moment magnitude scale has replaced the Richter scale, we will assume from here on that we are referring to moment magnitude, not Richter magnitude, when we speak of earthquake magnitude.<\/p>\n<p>The magnitude scale portrays energy logarithmically to approximately base 32. For example, a magnitude 6.0 earthquake releases about 32 times as much energy as a magnitude 5.0 earthquake. A magnitude 7.0 releases about 32\u00a0\u00d7\u00a032\u00a0=\u00a01024 times as much energy as a magnitude 5.0 earthquake. A magnitude 9.0 earthquake, which rarely occurs, releases over a million times as much energy as a magnitude 5.0 earthquake.<\/p>\n<h3>Ranking Earthquake Intensity<\/h3>\n<p>Earthquake intensity is very different from earthquake magnitude. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place. Therefore, each earthquake produces a range of intensity values, ranging from highest in the epicenter area to zero at a distance from the epicenter. The most commonly used earthquake intensity scale is the Modified Mercalli earthquake intensity scale. Refer to the <a href=\"http:\/\/earthquake.usgs.gov\/learn\/topics\/mercalli.php\" target=\"_blank\" rel=\"noopener\">Modified Mercalli Intensity Scale<\/a> page on the US Geological Survey Earthquake Hazards Program website for an abbreviated version.<\/p>\n<p>The table below shows approximately how many earthquakes occur each year in each magnitude range and what the intensity might be at the epicenter for each magnitude range.<\/p>\n<table title=\"Earthquake Magnitude, Frequency and Intensity\" cellpadding=\"5\" style=\"width: 75%;\">\n<tbody>\n<tr>\n<th style=\"width: 10%;\">Magnitude<\/th>\n<th style=\"width: 10%;\">Average number per year<\/th>\n<th style=\"width: 10%;\">Modified Mercalli Intensity<\/th>\n<th style=\"width: 70%;\">Description<\/th>\n<\/tr>\n<tr>\n<td align=\"center\">0 &#8211; 1.9<\/td>\n<td align=\"center\">&gt;1 million<\/td>\n<td align=\"center\">&#8212;<\/td>\n<td>micro &#8211; not felt<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">2.0 &#8211; 2.9<\/td>\n<td align=\"center\">&gt;1 million<\/td>\n<td align=\"center\">I<\/td>\n<td>minor &#8211; rarely felt<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">3.0 &#8211; 3.9<\/td>\n<td align=\"center\">about 100,000<\/td>\n<td align=\"center\">II &#8211; III<\/td>\n<td>minor &#8211; noticed by a few people<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">4.0 &#8211; 4.9<\/td>\n<td align=\"center\">about 10,000<\/td>\n<td align=\"center\">IV &#8211; V<\/td>\n<td>light &#8211; felt by many people, minor damage possible<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">5.0 &#8211; 5.9<\/td>\n<td align=\"center\">about 1,000<\/td>\n<td align=\"center\">VI &#8211; VII<\/td>\n<td>moderate &#8211; felt by most people, possible broken plaster and chimneys<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">6.0 &#8211; 6.9<\/td>\n<td align=\"center\">about 130<\/td>\n<td align=\"center\">VII &#8211; IX<\/td>\n<td>strong &#8211; damage variable depending on building construction and substrate<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">7.0 &#8211; 7.9<\/td>\n<td align=\"center\">about 15<\/td>\n<td align=\"center\">IX &#8211; X<\/td>\n<td>major &#8211; extensive damage, some buildings destroyed<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">8.0 &#8211; 8.9<\/td>\n<td align=\"center\">about 1<\/td>\n<td align=\"center\">X &#8211; XII<\/td>\n<td>great &#8211; extensive damage over broad areas, many buildings destroyed<\/td>\n<\/tr>\n<tr>\n<td align=\"center\">9.0 and above<\/td>\n<td align=\"center\">&lt; 1<\/td>\n<td align=\"center\">XI &#8211; XII<\/td>\n<td>great &#8211; extensive damage over broad areas, most buildings destroyed<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Magnitude \/ Intensity Comparison<\/h3>\n<p>The following table gives intensities that are typically observed at locations near the epicenter of earthquakes of different magnitudes.<\/p>\n<table class=\"tabular\">\n<tbody>\n<tr valign=\"top\">\n<th id=\"t1\">Magnitude<\/th>\n<th id=\"t2\">Typical Maximum<br \/>\nModified Mercalli Intensity<\/th>\n<\/tr>\n<tr>\n<td headers=\"t1\"><b>1.0 &#8211; 3.0<\/b><\/td>\n<td headers=\"t2\"><b>I<\/b><\/td>\n<\/tr>\n<tr>\n<td headers=\"t1\"><b>3.0 &#8211; 3.9<\/b><\/td>\n<td headers=\"t2\"><b>II &#8211; III<\/b><\/td>\n<\/tr>\n<tr>\n<td headers=\"t1\"><b>4.0 &#8211; 4.9<\/b><\/td>\n<td headers=\"t2\"><b>IV &#8211; V<\/b><\/td>\n<\/tr>\n<tr>\n<td headers=\"t1\"><b>5.0 &#8211; 5.9<\/b><\/td>\n<td headers=\"t2\"><b>VI &#8211; VII<\/b><\/td>\n<\/tr>\n<tr>\n<td><b>6.0 &#8211; 6.9<\/b><\/td>\n<td headers=\"t2\"><b>VII &#8211; IX<\/b><\/td>\n<\/tr>\n<tr>\n<td headers=\"t1\"><b>7.0<\/b> and higher<\/td>\n<td headers=\"t2\"><b>VIII<\/b> or higher<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Abbreviated Modified Mercalli Intensity Scale<\/h3>\n<ol>\n<li>Not felt except by a very few under especially favorable conditions.<\/li>\n<li>Felt only by a few persons at rest, especially on upper floors of buildings.<\/li>\n<li>Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.<\/li>\n<li>Felt indoors by many, outdoors by few 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.<\/li>\n<li>Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.<\/li>\n<li>Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.<\/li>\n<li>Damage negligible in buildings 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.<\/li>\n<li>Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.<\/li>\n<li>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.<\/li>\n<li>Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.<\/li>\n<li>Few, if any (masonry) structures remain standing. Bridges destroyed. Rails bent greatly.<\/li>\n<li>Damage total. Lines of sight and level are distorted. Objects thrown into the air.<\/li>\n<\/ol>\n<div class=\"textbox exercises\">\n<h3>Check Your Understanding<\/h3>\n<p>The Richter Scale measures what?<\/p>\n<ul>\n<li>the total energy released by an earthquake<\/li>\n<li>the largest jolt of energy caused by an earthquake<\/li>\n<li>the damage caused by an earthquake<\/li>\n<\/ul>\n<details>\n<summary>Show Answer<\/summary>\n<p>the largest jolt of energy caused by an earthquake<\/p>\n<\/details>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2023\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Introduction to Magnitude and Intensity. <strong>Authored by<\/strong>: Kimberly Schulte and Lumen Learning. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>7.3: Measuring and Predicting Earthquakes. <strong>Provided by<\/strong>: CK-12. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/7.3\/\">http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/7.3\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><li>Basics -- Earthquakes. <strong>Authored by<\/strong>: Ralph L. Dawes and Cheryl D. Dawes. <strong>Provided by<\/strong>: Wenatchee Valley College. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/commons.wvc.edu\/rdawes\/G101OCL\/Basics\/earthquakes.html#seismlgy\">http:\/\/commons.wvc.edu\/rdawes\/G101OCL\/Basics\/earthquakes.html#seismlgy<\/a>. <strong>Project<\/strong>: Geology 101 - Introduction to Physical Geology. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">All rights reserved content<\/div><ul class=\"citation-list\"><li>Measuring Earthquakes. <strong>Authored by<\/strong>: NASASciFiles&#039;s channel. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/wtlu_aDteCA\">https:\/\/youtu.be\/wtlu_aDteCA<\/a>. <strong>License<\/strong>: <em>All Rights Reserved<\/em>. <strong>License Terms<\/strong>: Standard YouTube License<\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">Public domain content<\/div><ul class=\"citation-list\"><li>Magnitude \/ Intensity Comparison. <strong>Provided by<\/strong>: USGS. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/earthquake.usgs.gov\/learn\/topics\/mag_vs_int.php\">http:\/\/earthquake.usgs.gov\/learn\/topics\/mag_vs_int.php<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/about\/pdm\">Public Domain: No Known Copyright<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":4,"template":"","meta":{"_candela_citation":"[{\"type\":\"original\",\"description\":\"Introduction to Magnitude and Intensity\",\"author\":\"Kimberly Schulte and Lumen Learning\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"7.3: Measuring and Predicting Earthquakes\",\"author\":\"\",\"organization\":\"CK-12\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/7.3\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"},{\"type\":\"copyrighted_video\",\"description\":\"Measuring Earthquakes\",\"author\":\"NASASciFiles\\'s channel\",\"organization\":\"\",\"url\":\"https:\/\/youtu.be\/wtlu_aDteCA\",\"project\":\"\",\"license\":\"arr\",\"license_terms\":\"Standard YouTube License\"},{\"type\":\"pd\",\"description\":\"Magnitude \/ Intensity Comparison\",\"author\":\"\",\"organization\":\"USGS\",\"url\":\"http:\/\/earthquake.usgs.gov\/learn\/topics\/mag_vs_int.php\",\"project\":\"\",\"license\":\"pd\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"Basics -- Earthquakes\",\"author\":\"Ralph L. 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