Earthquake earthquakes are sudden, violent shaking of the earths crust. In the 1930s charles richter developed a magnitude scale richter scale which was an. Click next to learn about the types of ground movement that affect utilities. The intensity of an earthquake at a location is a number that characterizes the severity of ground shaking at that location by. The modified mercalli intensity scale sandiegocounty. Earthquake magnitude, intensity, energy, and acceleration 107 be about 16 kin. Geological survey emeritus tadahiro kishida khalifa university of science and technology peer report no.
Sp23 earthquake basics the delaware geological survey. 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. Pdf the comparison of intensity assessments based on macroseismic data and earthquake environmental effects eee is presented. Earthquake intensity is very different from earthquake magnitude. Earthquake magnitude an earthquakes magnitude is a measure of the energy released at the sourceof the earthquake. The fourth pre1900 earthquake was an intensity vi shock that struck dillon november 4, 1897. Generally destruction is described in terms of damage caused to. An earthquake causes many different intensities of shaking in the area of the epicenter where it occurs. Generally destruction is described in terms of damage caused to buildings, dams, bridges and other structures. Magnitude versus intensity lesson pdf classroom lesson to teach the difference between earthquake magnitude and earthquake intensities 8. This is a rough numerical scale to describe how severe an earthquake is in the place where youre standinghow bad it is on a scale of 1 to 10. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place.
As a rule, seismic intensities announced by jma are values observed using seismic intensity meters installed on the ground or on the first floor of lowrise buildings. However, m w is a static measure, depending only on the area of fault that moves, the average slip, and the rigidity of the surround. In 1509, the ix intensity earthquake caused many people to lose their lives, caused a. Show students a film clip of an earthquake or ask if anyone in the class has ever been in an earthquake.
Magnitudes are usually determined from measurements of an earthquakes seismic waves as recorded on a seismogram. A relative earthquake hazard activity that includes effects of nearsurface geology and liquefaction potential in portland, oregon. Pdf earthquake hazard and the environmental seismic intensity. The epicenter is the point on earths surface directly above the focus. Before we start, lets talk about earthquakes and how we measure their intensity. This scale defines earthquake intensity by taking into consideration the occurrence, size and. The severity of an earthquake usgs publications repository.
Earthquake resistant building construction seminar and ppt with pdf report. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking quaking caused by an earthquake at a given location. In 1935 charles richter defined the magnitude of an earthquake to be. Shaking intensity from injectioninduced versus tectonic. Measuring earthquakes magnitude and intensity the size of an earthquake is described in terms of magnitude, which is a measure of the amplitude of a seismic wave and is related to the amount of energy released during an earthquake. E ach w h o len u m b er in crease in m ag n itu d e o n th e r ich ter scale rep resen ts an in crease in m easu red am p litu d e b y a facto r o f 1 0. The following is an excerpt from intensity distribution and isoseismal maps for the northridge, california, earthquake of january 17,1994.
The results are rapidly available via the web through a variety of map. The focus is the point on the fault surface where motion begins. R package for computation of earthquake groundmotion response spectra pengfei wang jonathan p. From the film clip or description, ask students to describe the ways in which the earths crust is displaced during an earthquake. Definition of an earthquake an earthquake also known as a quake, tremor or temblor is the result of a sudden release of energy in the earths crust that creates seismic waves. A number of assumptions are necessary when the maximum intensity is used in a study of earthquake frequency. The great tangshan earthquake of 1976 caltechauthors. Catalog header descriptions projection and datum consistently used for all data files. Earthquake a sudden slipping or movement of a portion of the earths crust accompanied and followed by a series of vibrations. The size of the earthquake is called its magnitude. Intensity and intensity scales gfzpublic gfzpotsdam. Well, everyone knows about the earthquake and an earthquake is an oscillation or the quivering. R package for computation of earthquake ground motion.
Seismic magnitude scales are used to describe the overall strength or size of an earthquake. Introduce the story on master 2, the turtle tale, and read it aloud. The following are best practices to prepare for earthquakes. Scientists also talk about the intensity of shaking from an. Geological survey emeritus tadahiro kishida khalifa university of science technology and research. Scientists also talk about the intensity of shaking from an earthquake, and this varies depending on where you are during the earthquake. Earthquake size is a quantitative measure of the size of the earthquake at its source. Abridged from the severity of an earthquake, usgs general interest publication 19892889 history and details of mmi. The effect of an earthquake on the earths surface is called the intensity. R package for computation of earthquake ground motion response spectra pengfei wang jonathan p. Earthquakes arent predictable, so the best practice is to always be prepared. Narrated effects of nearsurface geology on intensity of ground shaking. Earthquake intensity suggestion for class discussion.
The dss helps understanding what the actual impact and priority needs after an. Intensity scales, like the modified mercalli scale and the rossiforel scale, measure the amount of shaking at a particular location. Intensity, magnitude, location, and attenuation in india for. The richter magnitude scale measures the amount of seismic energy released by an earthquake. This scale could probably be used to measure intoxication. Prepare learn what you can do to prepare for an earthquake before, during, and after. Learn what you can do to prepare for an earthquake before, during, and after. This animation describes the main factors that contribute to differing intensities using examples of earthquakes.
Defining an earthquakeunit i, level 1, grades k2 i 2. However, larger and potentially damaging induced earthquakes have occurred in the past. Over 14,000 residents of the region were killed as poorly constructed. As with any word problem, the trick is convert a narrative statement or question to a mathematical statement.
Occasionally, when a large earthquake occurs, longperiod seismic waves reach locations far from the hypocenter. What is the difference between magnitude and intensity. Robert mallets intensity map of the 1857 italy earthquake. M a t h s k il l s u s e d 43 a r t h c ie n c e ear. Introduction and video step 1 understand the earthquake threat step 2 identify vulnerable assets and determine consequences step 3 pursue mitigation. Earthquake intensity mustafa fahmi hasanmustafa mohammed rashid 2011 november 2. Earthquake intensity scale earthquakes in japan the. Earthquake intensity incorporated research institutions. Earthquake building damage and earthquake engineering computer animations. The length of the wiggle depends on the size of the fault, and the size of the wiggle depends on the amount of slip. The majority of earthquakes occur at shallow depths that.
Measuring earthquakes california academy of sciences. Intensity of an earthquake is a measure of its effect, i. It is one of the service agencies of the department of science and technology. The intensity or destructive power of an earthquake is an evaluation of the severity of ground motion at a given location. Before an earthquake during an earthquake after an earthquake for more information on earthquake. Wood and frank neumann the formation of a satisfactory earthquake intensity scale has long been a subject for consideration and discussion among those who are in terested actively in studies. Definition of an earthquake an earthquake also known as a quake, tremor or temblor is the result of a sudden release of energy.
Intensity is a measure of an earthquake determined from the observed effects, especially damage. The main sources of data used in compiling the earthquake intensity database earthquake history of the united states this publication is a summary of all earthquakes intensity v and above that have occurred in the united states and its territories from earliest recorded history about 1638 in the new england region through 1980. Modified mercalli intensity scale of 1931 by harry o. Most earthquakes occur along zones where the earths crust is undergoing deformation. Scientists also talk about the intensity of shaking from an earthquake, and this varies depending. Intensity, magnitude, location, and attenuation in india. Measuring earthquake intensities using seismic scales. The richter magnitude scale measures the amount of seismic energy released by an earthquake when an earthquake occurs, its magnitude can be given a single numerical. The severity of earthquake shaking is assessed using a descriptive scale the modified mercalli intensity scale. The principal assumptions are that all of the earthquakes in the area considered occurred at approxibately the same focal depth and that the. Shortcomings of intensity scales not directly related to earthquake source damage obviously distancedependent needs population to report damage affected by site response example of intensity maps for 1886 charleston, usa, earthquake. Clearly, the severity of shaking is much higher near the epicenter than farther.
Seismograms come in handy for locating earthquakes too. For a given earthquake, intensity normally decreases with distance from the epicentre. Mar 10, 2019 the first measuring tool invented for earthquakes was the seismic intensity scale. So the intensity of an earthquake will vary depending on where you are. How can scientists tell where the earthquake happened. Seismic intensity scale forget the richter scale, tokyos minato ward has a far more helpful and amusing scale for judging earthquake intensity, their seismic intensity scale. The magnitude of an earthquake is thus represented by a. Pdf earthquake intensity assessment based on environmental. Magnitude is a measure of the seismic energy released in the earthquake. Why are some earthquakes more destructive than others. The first measuring tool invented for earthquakes was the seismic intensity scale. Introduction to the earthquake intensity database ncei.
The magnitude of a standard earthquake is richter studied many earthquakes that occurred between 1900 and 1950. The largest earthquake in montanas history was the magnitude 7. Magnitude and intensity are terms used to describe the severity of an earthquake. R ichter math t h e r ich ter scale is b ased o n a m ath em atical sy stem. This document describes the phenomena and damage that may be observed for individual seismic intensity levels. For an earthquake of given richter magnitude, intensity will vary with distance from epicenter, local geology, construction practices, etc. The intensity scale consists of a series of certain key responses such as people awakening, movement of furniture, damage to chimneys, and finally total destruction. Earthquake and seismic intensity information locationmagnitude and regions with seismic intensity of 3 or greater. The point on the fault surface where movement begins, the earthquake source, is termed the focus.
The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates. Comparison of magnitude, intensity, and energy equivalent for earthquakes. When this stress becomes great enough to rupture the crust, or to overcome the friction that prevents one block of crust from slipping past another, energy is released, some of it in the form of various kinds of seismic waves that cause groundshaking, or quaking. The observations can then be compiled to make macroseismic maps showing lines of equal intensity. Learn about earthquake severity, or intensity scales. In addition to archiving historic data from the early years, the usgs has also worked to archive photos and descriptions of.
Preserving historic earthquake records and photos of the instruments that recorded them a project to scan a small selection of the film chips of historical earthquake recordings to digital files was started in 1996. A intensity attenuation law and ground motion amplitude 87. Pdf on the use of jma intensity in earthquake early. This emergency action plan eap outlines the appropriate actions that employees, students, and visitors at wright state university should take before, during, and after an earthquake. Learning earthquake tip 3 earthquake design and construction.
Neither earthquake magnitude nor macroseismic intensity provides sufficient information to. In few cases the earthquake is fierce to the surface of the earth which delivers the energy in the crust of the earth, coming to the released energy then it is a quick and unexpected displacement of the parts of the crust. It is measured in relation to the effects of the earthquake on human life. Earthquake resilience guide for water and wastewater utilities. They are caused when the earths tectonic plates move, rub, collide, or break apart. This means that the magnitude of the earthquake is a single value for a given earthquake. 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. Earthquake intensity british geological survey bgs.
Earthquake intensity scale earthquakes in japan the tokyo. Aftershock an earthquake of similar or lesser intensity that follows the main earthquake. Earthquake 3 of 4 n provide retaining straps on cclamps and replace powderdriven fasteners, if used in hanger assemblies. Pdf the main objective of this paper was to introduce the environmental seismic intensity. Earthquake magnitude, intensity, energy, and acceleration by. Jul 15, 2015 earthquake intensity scale earthquakes in japan i.
Its like when youre teacher loses their marbles because youve asked them the same question 7 times in a row. Earthquake resistant building construction pdf and ppt. Magnitude is commonly expressed by ratings on the moment magnitude scale mw, the most common scale used today usgs 2017. The earthquake caused the failures of the electric power system, the water supply system, the sewer system, the. Seismic intensity is an index that describes the effects on people, objects and buildings that are observed. Effects of nearsurface geology on intensity of ground shaking.
Intensity, magnitude, location, and attenuation in india for felt earthquakes since 1762 by walter szeliga, susan hough, stacey martin, and roger bilham abstract a comprehensive, consistently interpreted new catalog of felt intensities for india martin and szeliga, 2010, this issue includes intensities for 570 earth. Earthquake intensity what is felt during an earthquake at any given location is often mistaken for earthquake magnitude the instrumentally measured size of that earthquake. A new seismic risk map of the united states is presented. Earthquakes january 2012 page 1 of 20 document objective this disaster summary sheet dss provides a general profile of the potential impact of an earthquake. Earthquake foci plural of focus occur at a range of depths. On the other hand, intensity is an indicator of the severity of shaking generated at a given location. Wood and frank neumann the formation of a satisfactory earthquake intensity scale has long been a subject for consideration and discussion among those who are in terested actively in studies of shock intensity and its geographic mani festation. The deadly izmit earthquake struck northwest turkey on august 17, 1999, at 3 a.
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