Intensity of earthquake pdf

Seismic intensity scales categorize the intensity or severity of ground shaking quaking at a given location, such as resulting from an earthquake. 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. The legend shows a color code for shaking potential. Choose from 69 different sets of earthquake intensity flashcards on quizlet. In an effort to identify optimum intensity measures, a com. It was proposed by chilean engineer arturo arias in 1970 it is defined as the timeintegral of the square. The intensity of ground shaking and other earthquake effects the structure. Seismic magnitude scales are used to describe the overall strength or size of an earthquake.

In the event of an earthquake, telephone line congestion may occur as a result of increased use related to safety confirmation around regions of strong shaking. Earthquake intensity mustafa fahmi hasanmustafa mohammed rashid 2011 november 2. In this lesson, you will compare the intensity of earthquakes. The intensity or destructive power of an earthquake is an evaluation of the severity of ground motion at a given location.

Or, try our realtime notifications, feeds, and web services. Therefore, each earthquake produces a range of intensity values, ranging from highest in the epicenter area to zero at a distance from the epicenter. An earthquake intensity scale can be used in two different ways. Perceptible to people under favorable circumstances. Cassidy and others published earthquake intensity find, read and cite all the research you need on researchgate. 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 sei. Feb 23, 2017 top 5 weird ww2 german prototypes that actually flew duration. An earthquake will have different intensities in different places. Usgs resources and links to outside educational resources. Earthquake intensity an overview sciencedirect topics. Usgs fema earthquake intensity and classification are commonly measured using two. This means that the magnitude of the earthquake is a single value for a given earthquake.

An earthquake has to reach a magnitude of 5 on the richter scale, how much greater in intensity is the second earthquake compared to the first one. Earthquake and seismic intensity information locationmagnitude and regions with seismic intensity of 3 or greater. Assessment of arias intensity of historical earthquakes. The earthquake event page application supports most recent browsers, view supported browsers. Intensity scales, like the modified mercalli scale and the rossiforel scale, measure the amount of shaking at a particular location.

It determines the intensity of shaking by measuring the acceleration of transient seismic waves. The usgs and its partners monitor and report earthquakes, assess earthquake impacts and. These earthquakes are a result of movement of tectonic plates beneath the earths crust. Earthquake magnitude, intensity, energy, and acceleration. Is of torsion seismometers and uscgs accelerographs. The intensity is a number written as a roman numeral describing the severity of an earthquake in terms of its effects on the earths surface and on humans and their structures.

Foreword on the basis of the detailed macroseismic study of the 21 may, 2003 zemmouri earthquake mw 6. 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. It is therefore wrong to refer to the intensity of an earthquake. Based on the phivolcs earthquake intensity scale peis, intensity 7 is destructive, while 8 and 9 are very destructive and devastating, respectively. Earthquake intensity definition and meaning collins. Philvolcs cites seismic scale specifically developed for the philippine setting, the different geography of each country and other. White circles, site intensities dimension proportional to 5.

Earthquake intensity earthquake intensity is defined as the strength of seismic shaking at a given location. In some cases, only one intensity is listed for an earthquake. The dangers of earthquakes are presented as well as the necessity for engineers to design structures for earthquakeprone areas that are able to withstand the forces of seismic waves. Assessment of arias intensity of historical earthquakes 3099 table 1. Earthquakes are natural disasters that take place in different parts of the world causing much devastation and loss of property and lives. Difference between magnitude and intensity of earthquake. Thus it is clear that magnitude is a fixed value independent of distance from the epicenter of the earthquake, whereas intensity varies and is measured differently at different places depending upon its distance from the epicenter. The length of the wiggle depends on the size of the fault, and the size of the wiggle depends on the amount of slip. Intensity is a measure of the strength of shaking experienced in an earthquake. Horizontal ground accelerations for the operating basis earthquake and safe shutdown earthquake for nuclear. The 1976 tangshan earthquake, also known as great tangshan earthquake, was a natural disaster resulting from a magnitude 7.

However, it can be considered to be even more useful, since seismic risk studies are concerned with establishing the probability of damage or loss occurring, and intensity is a direct. So the intensity of an earthquake will vary depending on where you are. Students learn how engineers build shake tables that simulate the ground motions of the earth caused by seismic. For a given earthquake, intensity normally decreases with distance from the epicentre. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place. The observations can then be compiled to make macroseismic maps showing lines of equal intensity. There are several earthquake intensity scales, which can be referred from the relevant pages. Learn more about the causes and effects of earthquakes in this article. 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. Earthquake intensity scales date back to the late eighteenth century e.

Difference between earthquake magnitude and intensity. They are distinguished from seismic magnitude scales, which measure the magnitude or overall strength of an earthquake, which may, or perhaps not, cause perceptible shaking. He assigns intensity values to each locality using a macroseismic scale. The usefulness of earthquake intensity in seismic hazard estimation carries over into seismic risk studies in very similar ways. Usgs fema earthquake intensity and classification are commonly measured using two different scales, the maximum modified mercalli intensity scale mmi and the richter magnitude scale often shortened to richter scale. Mercalli scale projected earthquake intensity 6 reinsurance price index for us, 1990 2015 9 average annual premium for residential earthquake coverage, by region, 20002014 11 percent difference in annual premium. Earthquake intensity incorporated research institutions for. Fun and educational resources including science fair ideas and earthquake science you can understand. The phivolcs earthquake intensity scale peis is a seismic scale used and developed by the philippine institute of volcanology and seismology philvolcs to measure the intensity of an earthquake it was developed as a response to the 1990 luzon earthquake. Learn earthquake intensity with free interactive flashcards. In the analysis of earthquake tsunami we usually use the moment magnitude m w. For example, the recent san simeon earthquake before christmas 2003 had a maximum intensity of viii. Clearly, the severity of shaking is much higher near the epicenter than farther.

The usgs earthquake hazards program is part of the national earthquake hazards reduction program nehrp, established by congress in 1977, and the usgs advanced national seismic system anss was established by congress as a nehrp facility. Pdf attenuation of intensity for the zemmouri earthquake of. Science briefs about new earthquake research written for nonscientists. 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. Table 1 presents the difference between magnitude and intensity of earthquake. Learning earthquake tip 3 earthquake design and construction. Students learn about the types of seismic waves produced by earthquakes and how they move the earth. 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. The modified mercalli scale represents the local effect or damage caused by an earthquake.

Scientists also talk about the intensity of shaking from an. On the richter scale, the magnitude of an earthquake is related to the released energy e in joules j by the equation. Intensity is a measure of an earthquake determined from the observed effects, especially damage. In minutes, eightyfive percent of the buildings in tangshan collapsed or were unusable, all services failed, and most of the highway and railway. Both magnitude and intensity are expressions of the amount of energy released when a fault ruptures. Intensity is usually given in roman numerals in order to avoid confusion with magnitudes. Generally destruction is described in terms of damage caused to buildings, dams, bridges and other structures. Suppose an earthquake occurred whose center was in richmond, va. The size of the earthquake is called its magnitude. Earthquake intensity british geological survey bgs. Intensity scale it manifests the degree of damage, which gets diminished as we go away from the main shock source zone and the reverse is also true5.

The intensity range, from i xii, is expressed in roman numerals. It measures the effects of an earthquake at a given location, distinguished from the earthquake s inherent force or. Performancebased earthquake engineering, ground motion intensity measures abstract. Understanding the magnitude and intensity of an earthquake. The arias intensity i a is a measure of the strength of a ground motion. Ground motion intensity measures for performancebased. 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. In general, only if the earthquake magnitude reaches above 6. The paper investigates the principal physical elements of earthquakes. It is measured in relation to the effects of the earthquake on human life.

A critical issue in the pr obabilistic framework for performa nce based earthquake engineering is the choice of ground motion intensity m easures. The earthquake shaking felt and reported is described through something called. Why are some earthquakes more destructive than others. A citsci approach for rapid earthquake intensity mapping. Thus, intensity maps for historical earthquakes tend. Seiche the sloshing of a closed body of water from earthquake shaking. Delicately balanced objects are disturbed slightly. Mar 24, 2020 earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. Definition of an earthquake an earthquake also known as a quake, tremor or temblor is the result of a sudden release of energy. They are distinguished from seismic magnitude scales, which measure the magnitude or overall strength of an earthquake, which may, or perhaps not, cause perceptible shaking intensity scales are based on the observed effects of the shaking, such. Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. Earthquake intensity is very different from earthquake magnitude. The richter magnitude scale measures the amount of seismic energy released by an earthquake. The correlation between intensity and magnitude of earthquake are provided in table 4.

You can click on legend to see what the color codes mean. Magnitudes are usually determined from measurements of an earthquakes seismic waves as recorded on a seismogram. The conventional use which will be termed here the forwards use is the one that most people will be familiar with. This animation describes the main factors that contribute to differing intensities using examples of earthquakes.

Whereas an earthquake has just a single magnitude, it will have many different intensities at different locations. The intensity at the epicentre of the 1989 loma prieta earthquake was intensity 8. The colors represent modified mercalli intensity mmi values, with the bottom dark brown color representing a. Paret3 summary the earthquake engineering intensity scale eeis is a building shaking intensity measure that has been developed along the lines of the engineering intensity scale of the late john a. If the area of anomalous intensity is bigger than the area of the meizoseismal area i. R is the epicentral distance, mw is the body wave magnitude, soil parameter is 0 for rock vs 800ms. Earthquake magnitude and intensity are two dimensions of the earthquake.

Earthquake magnitude, intensity, energy, and acceleration 107 be about 16 kin. 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. Earthquake magnitude, intensity, energy, and acceleration by. Amplitudes at the uscgs locations have been divided by an average factor of 2 12 to compensate for difference in ground. Intensity decreases as we move farther from the epicenter. Procedures for estimating earthquake ground motions. It has been found to be a fairly reliable parameter to describe earthquake shaking necessary to trigger landslides. Mar 12, 2011 difference between earthquake magnitude and intensity. The earthquake size is usually expressed as the earthquake magnitude and intensity. What is the difference between magnitude and intensity. Comparison between the macroseismic effects of the 2016 august and october main shocks. Proceedings of the 10th national conference in earthquake engineering, earthquake engineering research institute, anchorage, ak, 2014.

Pdf a citsci approach for rapid earthquake intensity. The macroseismic intensity distribution of the 30 october. To combat this, telecommunications providers offer message boards and message dial services for use in disasters resulting from earthquakes with a seismic intensity of about 6 lower or. It is one of the service agencies of the department of science and technology. Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another. The severity of earthquake shaking is assessed using a descriptive scale the modified mercalli intensity scale. Pdf attenuation of intensity for the zemmouri earthquake. Factors that affect a structures seismic risk include. Rapid estimate of ground shaking intensity by combining simple earthquake characteristics with tweets. Several scales exist, but the ones most commonly used in the united states are the modified mercalli scale and the rossiforel scale. Earthquake size is a quantitative measure of the size of the earthquake at its source.