Mmi refers to the modified mercalli scale, a commonly accepted method of characterizing ground. Modified mercalli intensities for nine earthquakes in central and. Home connections send home the shake, rattle, and roll family activity packets, which should include. Richters version became instead the modified mercalli scale of 1956 mm56. This video explains the mercalli intensity scale, a subjective scale that describes different levels of shaking and damage caused by earthquakes. What is the difference between magnitude and intensity. Modified mercalli intensity mmi scale abbreviated version.
Revisions in this version of the scale are shown in italics. Felt indoors by many, outdoors by few, some awakened at night, dishes, windows, doors, rattle and move, stationary cars rock. We will be using data from reports of an earthquake that struck california in 1989 and the modified mercalli scale. Modified mercalli intensity how is modified mercalli intensity abbreviated. Because of these shortcomings, moment magnitude is the most common scale used by the united states geological survey usgs. The hypocenter is the exact point underground along a fault where the slippage of the two blocks of rock occurs. Generate, develop, test and communicate design ideas, plans and processes for. In this study, the previously reported isoseismal maps are compiled and used to carefully investigate the macroseismic intensity in terms of the modified mercalli intensity mmi scale, based on the engineering groundmotion parameter, as the peak ground acceleration pga, inferred from the groundmotion attenuation characteristic of myanmar.
It measures the shaking you feel during an earthquake. It is advisable to plan such investigations as much as possible before an. Pdf the modified mercalli intensity scale revisions. The lower levels of the intensity scale indicate the effect of earthquake. Students examine the difference between magnitude and intensity in earthquakes. The modified mercalli scale measures how people feel and react to the shaking. Mercalli scale vs richter scale difference and comparison. Review the roman numerals and read their descriptions. So the intensity of an earthquake will vary depending on where you are. An earthquake causes many different intensities of shaking in the area of the epicenter where it occurs. Wood, and frank neumann, modified mercalli s 12value scale into what we use today. Adapted from siebergs mercalli cancani scale, modified and condensed. Find mercalli intensity scale lesson plans and teaching resources. Geological survey and prior to 1973 by agencies in the u.
Mercalli intensity scale simple english wikipedia, the. In new zealand, where earthquakes occur from near the surface right down to a depth of over 600 km, the modified mercalli intensity scale is a better indicator of an earthquakes effects on people and their environment. Rather, they classify earthquakes by the effects they have and the destruction they cause. Kathryn davis department of geography nathan wood, ph. The mercalli intensity scale is a seismic scale uised for measurin the intensity o an yirdquauk. Elastic rebound refers to how the slippage along a fault i. Intensities assigned from questionnaire data may not even be accurate to a. It measures the effects of an earthquake at a given location, distinguished from the earthquakes inherent force or strength as measured by seismic magnitude scales such as the. Marginal and longperiod effects of large earthquakes.
The modified mercalli scale measures how people feel and react to. In santa clara county aresraces, we use the modified mercalli intensity scale for efficient and standardized reporting of earthquake damage. When there is little damage, the scale describes how. It is known today as the modified mercalli intensity scale. That gave the mercalli scale, as well as the followed european msk64 scale, the quantitative element, which reprisents the vulnerability of the buildings type.
The modified mercalli mm intensity scale the mm intensity scale is the commonly used scale to describe the intensity of the earthquake. Display the modified mercalli scale on the overhead projector. The intensity of an earthquake is listed along with effects on the modified mercalli scale in this printable guide. Modified mercalli intensity scale, liquid sand, liquefaction, new madrid seismic zone, lateral spread landslides, interagency exercise director douglas n. Earth science earthquakes, volcanoes and plate tectonics file. Modified mercalli scale how is modified mercalli scale. Modified mercalli scale intensity effects pga gals i not felt. The mercalli intensity scale or more precisely the modified mercalli intensity scale is a scale to measure the intensity of earthquakes. The preliminary relationship be tween the mmi and pga is reported to be a function of log.
As you can see here, as the numbers get higher, the more you feel the shaking. The modified mercalli intensity mmi estimates the intensity of shaking from an earthquake at a specific location or over a specific area by considering its effects on people, objects, and buildings. Helps students understnad difference between magnitude and intensity. The mercalli scale uses twelve steps to describe damage to structures. However, routine practice in japan seems to be largely to rely on estimates of. Instead of using vague and subjective descriptions like major, minor or heavy, a mikemike value is reported. The methods of presentation and routine data reporting can. Modified mercalli intensity scale mmi the modified mercalli intensity mmi estimates the intensity of shaking from an earthquake at a specific location or over a specific area by considering its effects on people, objects, and buildings. They use the modified mercalli intensity scale and newspaper articles to estimate the strength and effects of a past earthquake. The modified mercalli intensity scale, us government. The epicenter is the point on earths surface that is directly above the hypocenter. Watch this video, and you will be an expert on it all. Relationship between modified mercalli intensity and peak.
Modified mercalli scale intensity effects pgagals i not felt. A comparison of two versions of modified mercalli intensity for earthquake exposure assessment by jamie l. Find richter and mercalli scales lesson plans and teaching resources. Modified mercalli intensity scale damage potential x very light. It is actually a measurement of the size of the waves produced by the earthquake. Mar 20, 20 have you ever wondered about who invented the mercalli intensity scale. The intensity o an yirdquauk is nae tot determined bi its magnitude. Have you ever wondered about who invented the mercalli intensity scale.
Modified mercalli intensity scale, the a description of the modified. Intensity scales, like the modified mercalli scale and the rossiforel scale, measure the amount of shaking at a particular location. A 10value scale which had been in use in europe since 1883 was refined in 1902 by an italian seismologist, giuseppe mercalli. The richter scale is a mathematical measurement of the intensity of the ground shaking, as measured on a seismograph. The mmi scale estimates the shaking strength of an earthquake at a specific location, such as the epicenter, or over a specific area by considering its. The strength of an earthquake is usually measured on one of two scales, the modified mercalli scale and the richter scale. For example, an earthquake intense enough to be felt by a person standing nearby is said to have an intensity of mm iii. Map of earthquake and tsunami damage potential for a open. Modified mercalli intensity how is modified mercalli. The first scale furnishes an evaluation magnitude of the quantity of freed energy, while the seconds scale assigns a degree to the effects on the. It measurs the effects o an yirdquauk, an is distinct frae the moment magnitude uisually reportit for an yirdquauk whiles misreportit as the richter magnitude, which is a measur o the energy released. Handout primarily discussing the modified mercalli scale.
The mercalli scale is a rather arbitrary set of definitions based upon what people in the area feel, and their observations of damage to buildings around them. Geological society of america abstracts with programs, v. The relationship between richter magnitude and modified. Moment magnitude is a different measure from the richter scale, which was designed in 1935 for small to medium earthquakes in california, within 600 km of the recording seismograph. Intensity and intensity scales gfzpublic gfzpotsdam. This scale, composed of increasing levels of intensity that range from imperceptible shaking to. Modified mercalli intensity scale mmi abag resilience program. Department of commerce have for many decades been based on the modified mercalli intensity scale of 1931 wood and neumann, 1931, which we usually refer to simply as the modified mercalli or mm scale. The modified mercalli intensity scale for earthquake insurance. Risk management plans emergency restoration plans erp facility response plans onsite emergency response teams ert. The modified mercalli intensity scale simplified, from reference. This value is quick and simple to communicate over the air and equates to an objective. Set of programs, source and compiled versions menu driven. This scale is composed of 12 increasing levels of intensity, designated by roman numerals, ranging from imperceptible shaking to catastrophic destruction.
The mercalli intensity scale was developed by italian volcanologist giuseppe mercalli in 1884 and expanded to include 12 degrees of intensity in 1902 by adolfo cancani. Modifiedmercalliintensityscale earthquakedamagereporting byjohnjacobschmidt,amrron intheimmediateaftermathofanearthquake,searchandrecoveryeffortswill. The modified mercalli scale is designed to describe the effects of an earthquake, at a given place, on natural features, on industrial installations and on human. Maps drawn from reports of what people felt are useful in determining areas of damage concentration.
The modified mercalli intensity scale mmi is a useful tool for assessing earthquakerelated property risk. This scale is composed of 12 increasing levels of intensity, designated by roman numerals, ranging from imperceptible shaking to. They complete map work and write a first hand account of a person living in each level of intensity on the modified mercalli scale. The modified mercalli intensity scale mm or mmi, descended from giuseppe mercalli s mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. Lower numbers on the scale indicate less severe shaking. Mercalli intensity scale simple english wikipedia, the free. It measures the effects of an earthquake at a given location, distinguished from the earthquakes inherent force or. Magnitude versus intensity lesson pdf classroom lesson to teach the difference between earthquake magnitude and earthquake intensities 8. The modified mercalli intensity scale mm or mmi, descended from giuseppe mercallis mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. Modified mercalli intensity mmi scale is a subjective measurement of earthquake effects and damage.
The most widely used intensity scale, the modified mercalli scale, is divided into 12 degrees, each identified by a roman numeral. Unlike with the richter scale, the mercalli scale does not take into account energy of an earthquake directly. The intensity of the earthquakes is valued according to the richter scale charles francis richter 2641900 3091985 or the modified mercalli scale giuseppe mercalli 2151850 1931914. Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the united states is the modified mercalli mm intensity scale. Apr 20, 2018 this video explains the mercalli intensity scale, a subjective scale that describes different levels of shaking and damage caused by earthquakes. New zealand scientists have modified it further to suit new zealand conditions. Since then, that scale was called the modified mercali intensity scale mms and the evaluations of the seismic intensities became more reliable. Comparing richter and mercalli scales for students 8th 10th in this richter and mercalli scale learning exercise, students answer questions about these two types of scales and how to read each.
Modified mercalli intensity scale value description. For additional information about the modified mercalli intensity scale and the richter scale, visit the u. Spill of national significance 2007 us epa archive. Modified mercalli intensity scale of 1931, as originally abridged by wood and neumann. The modified mercalli intensity scale sandiegocounty.
Modified mercalli intensity scale mmi abag resilience. Mercalli intensity value modified mercalli intensity scale description peak ground acceleration % g i. The mmi scale estimates the shaking strength of an. The comparison of macroseismic intensity scales nerc open. Some intensity scales in the past, such as the modified mercalli scale in its 1956. Be sure you have an application to open this file type before downloading. While the mercalli scale measures the perceived damage, the richter scale magnitude is a quantitative measure of an earthquakes power, as the richter scale measures displacement via seismic waves. Instrumental not felt except by a very few under especially favorable conditions. Bulletin of the seismological society of america, 21, 277283. The modified mercalli intensity scale is a semiquantitative linear scale developed in 1931 by the american seismologists harry wood and frank neumann. It is composed of 12 increasing levels of intensity which range from ground shaking to catastrophic destruction.
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