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. And if an event is thousand times smaller, its size would be minus 1 on the richter scale. For large earthquakes the richter as well as body wave magnitude scales saturate. This corresponds to a ratio of intensities of 800,000,000, so the richter scale provides more manageable numbers to work with. Earthquake magnitude, intensity, energy, and acceleration by. It is actually so large that if an event of that magnitude occurred somehow, it would destroy the entire visible universe sev. A seismic station located 60 km from the epicenter of an earthquake, recorded the maximum height of the swaves to be 50 mm. The richter magnitude scale often shortened to richter scale is the most common standard of measurement for earthquakes. Charles richter, inventor of the richter magnitude scale.
Helps students understnad difference between magnitude and intensity. The richter magnitude scale was developed in 1935 by charles f. Richter of the california institute of technology in 1935. Negative magnitudes are allowed on richters scale, although such earthquakes are certainly very small. To determine the moment magnitude rating, seismologists measure the surface area of the. The richter scale also called the richter magnitude scale or richters magnitude scale is a measure of the strength of earthquakes, developed by charles f. Richter magnitude the picture on the left shows a short period woodanderson torsion seismometer. The moment magnitude scale is also a logarithmic scale, with each number denoting a 30 or more powerful magnitude than the previous number. Pdf the aim of obtaining a single scale for earthquake magnitudes has led many studies in the past to either develop relationships among. The richter magnitude scale assigns a magnitude number to quantify the energy released by an earthquake. Lori dengler notes on magnitude humboldt state university. The scale represents the magnitude of the earthquake. Photo taken on april 10, 2016 shows the view after an earthquake in rawalpindi, pakistan.
That is again where the ingenuity of a logarithmic scale comes in. Richter, had hoped that different magnitude scales could. Sp23 earthquake basics the delaware geological survey. Earth science earthquakes, volcanoes and plate tectonics file. Richter scale and the moment magnitude scale youtube.
Richer magnitude scale is a device or a standard used for measuring the earthquake. In figure 2, you can see the transform plate boundary, the san andreas running through california and the direction that the two plates are moving. The richter scale also called the richter magnitude scale or richters magnitude scale is a. It is a mathematical device designed to measure the magnitude of the earthquake in terms of the amount of energy released during an earthquake. Officially known as the richter magnitude scale, the richter scale is used to measure the strength of a quake and assign it a single. The richter scale was originally devised to measure the magnitude of earthquakes of moderate size that is, magnitude 3 to magnitude 7 by assigning a number that would allow the size of one earthquake to be compared with another. Richter scale magnitude surface wave magnitude moment magnitude scale. The richter scale is based on a reading from a seismograph a device that detects the waves sent out by an earthquake. The modified mercalli intensity scale mmi, developed in 1931, is the most. The richter scale, developed in the 1930s, is a base10 logarithmic scale, which defines. Relation between seismic moment m0 and surface wave magnitude ms a technical document from the university of tehran.
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. Moreover, moment magnitude is much more accurate than the richter magnitude, especially in case of large magnitudes. One earthquake may have different ratings depending on the damage at different locations. Moment magnitude tells you something about the physical size of the earthquake. Richter 1956 gave a rewritten version of the mm scale which is referred to mm scale 1956 version. Earthquake magnitude magnitudes are commonly measured using the richter scale or the moment magnitude scale. Earthquake magnitude richter magnitude local magnitude m. The richter scale, developed in the 1930s, is a base10 logarithmic scale, that defines magnitude as the logarithm o the ratio o the amplitude o the seismic waves tae an arbitrar, minor amplitude, as recordit on a staundardised seismograph at a staundart distance. The richter scale measures earthquakes by using seven different categories.
The scale represents the intensity of earthquake by analyzing the after effects like how many people felt it, how much destruction occurred etc. Earthquakes 4 earthquake energy magnitude richter magnitude scale quantitative scheme based upon maximum amplitude of strongest body wave. How are earthquakes measured using the richter scale. The scale is theoretically limitless, although the highest magnitude so far recorded was 9. January 1935, an instrumental earthquake magnitude scale pdf, bulletin of. Earthquake magnitude, intensity, energy, and acceleiation 109 provides the better magnitude standard at large distances should be reached as part of a contemplated revision of the magnitude scale. This magnitude would be considered a i on the mercalli intensity scale. Mccalpin pdf magnitude, energy and frequency of occurrence a description of the richter scale. The richter magnitude scale is a scale of numbers used to tell the power or magnitude of earthquakes.
Sep 25, 2017 this feature is not available right now. Earthquake size, as measured by the richter scale is a well known, but not well understood, concept. Charles richter with assistance from others at cal tech and is a scale that represents the overall magnitude of an earthquake. Richters magnitude scale richter magnitude approximate tnt equivalent example 1.
Measuring earthquakes california academy of sciences. The richter scale is a base10 logarithmic scale, which defines magnitude as the logarithm of the ratio of the amplitude of the seismic waves to an arbitrary, minor amplitude. Negative magnitudes are allowed on richter s scale, although such earthquakes are certainly very small. The scale was developed for temblors occuring in southern california. It is a mathematical device designed to measure the magnitude of the earthquake in terms of the amount of. Many people have the wrong impression that the richter magnitude is based on a scale of 10.
Richter studied many earthquakes that occurred between 1900 and 1950. Earthquakes are measured by the richter magnitude scale. Now lets use this equation meant for energies expressed in dynecm units to estimate the magnitude of the tiny earthquake we can make on a lab table. His scale worked like a seismogram, measured by a particular type of seismometer at a distance of 100 kilometers 62 mi from the earthquake. Some basic parameters of this scale include its measurement factor and the formula. Intensity scale description effects less than 2 micro not felt 2. There is a standard way to convert a seismic moment to a magnitude.
Denharn editor, quantification of earthquakes and the determination of source parameters. Charles richter developed the richter scale in 1935. At the time when richter began a collaboration with gutenberg, the only way to rate shocks was a scale developed in 1902 by the italian priest and geologist giuseppe mercalli. Thousands of new, highquality pictures added every day. The magnitude is expressed in absolute numbers from 110. Similarly, the difference between earthquakes of magnitude 3 and 7 4 points on the richter scale will be 10 4 in maximum ground motion.
Understanding the richter scale and moment magnitude scale. For example, the richter scale rating of 2 is ten times the force of a level 1. The richter magnitude scale m l, also richter scale assigns a magnitude nummer tae quantify the size o an yirdquauk. We generally hear the term richter scale which is related to the topic of earthquakes. An earthquake ten times smaller than a 2 would have a magnitude of 1. This is a measure of the strength of ground motion and has a scale of 1 12, but in roman numerals, its i xii.
Due to the logarithmic nature of earthquake magnitudes, a magnitude 100 earthquake literally could never happen on earth. The moment magnitude scale is newly devised scale for measuring the size of an earthquake visavis the energy released. Intro to earthquakes pennsylvania state university. Comparing the richter and moment magnitude scales the richter scale rates earthquakes based on the size of their seismic waves, as measured by seismographs. This is reported on a richter scale that increases by powers of ten. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Richter of the california institute of technology as a mathematical device to compare the size of earthquakes. The socalled richter scale also richter magnitude or richter magnitude scale, more accurately but informally richter s magnitude scale for measuring the strength size of earthquakes refers to the original magnitude scale developed by charles f. Duration magnitude for delaware geological survey seismic station ned located near newark, delaware. Magnitude of the richter scale activity teachengineering. Measuring earthquakes teacher and youth education, 2012 2. Richter scale simple english wikipedia, the free encyclopedia.
When rocks are pushed against each other, stress can. In a sense, magnitude involves steps of 10 because every increase of one magnitude represents a tenfold amplification of the ground motion. This scale saturates at around m7, because the high frequency waves recorded locally have wavelengths shorter than the rupture lengths of large earthquakes. The scale is defined such that a magnitude3 earthquake recorded on a wood anderson torsion seismometer at a distance of 100 km would write a record with a. The magnitude of a standard earthquake is richter studied many earthquakes that occurred between 1900 and 1950.
Be sure you have an application to open this file type before downloading. Magnitude 6 is 3 points more on the richter scale than magnitude 3, so a magnitude 6 earthquake has 10. Like the richter scale for estimating ml, the modified mercalli mm scale is popularly used for estimating the earthquake. The richter scale is logarithmic, that means that the amplitude of a magnitude 6 earthquake is ten times greater. Sep 04, 2016 the richter magnitude scale assigns a magnitude number to quantify the energy released by an earthquake. Moment magnitude, richter scale what are the different. Almost everyone has heard of the richter scale and. Handout primarily discussing the modified mercalli scale. Find richter scale stock images in hd and millions of other royaltyfree stock photos, illustrations and vectors in the shutterstock collection. Richter used observations of earthquakes in california to determine a reference event. This is used to express the level of seismic energy released by the earthquake. Richter scale measures the intensity of an earthquake. Richter developed the richter magnitude scale m l for measuring the strength amount of energy released of earthquakes in 1930s because of the various shortcomings of the m l scale, seismologists now use moment magnitude scale m w both the scales are logarithmic and are scaled to have roughly comparable numeric values.
Press reporters love the richter scale and will report any earthquake magnitude as a magnitude on the richter scale, however for any large earthquake that has made the news it is very unlikely that a richter or local magnitude is an appropriate scale. Pdf a local magnitude scale for southern italy researchgate. Earthquake summary posters for significant earthquakes. Moment magnitude scale measures the size of the seismic waves as shown on a. The following article provides a brief explanation on the measurement of earthquake magnitude with the help of this scale. Earthquakes and volcanoes sciencematters 1 richter scale lesson concept seismographs determine the magnitude of an earthquake by measuring its force and duration. The local magnitude ml of an earthquake as defined by. When rocks are pushed against each other, stress can build up.
The scale is fairly accurate when measuring low to. The moment magnitude scale rates earthquakes based on the total amount of energy they release. The scale is defined such that a magnitude3 earthquake recorded on a woodanderson torsion seismometer at a distance of 100 km would write a record with a. Each number on the richter scale indicates an increase of ten times the force of the previous number. The mercalli scale uses roman numerals and classifies earthquakes from i to xii, depending on how buildings and people responded to the tremor. Retaining the present defi nition based on trace amplitudes of torsion seismometers, it appears that neither. This was developed in 1979 to overcome the shortcomings of the historic richter scale. A graphical procedure for estimating the richter magnitude ml is then. The idea of a logarithmic earthquake magnitude scale was first developed by charles richter in the 1930s for measuring the size of earthquakes occurring in southern california using relatively highfrequency data from nearby seismograph stations. The richter scale uses the amplitude of the largest wave recorded by a seismometer and the distance between the earthquake and seismometer. Richter and presented in his landmark 1935 paper, where he called it the magnitude scale.
This was later revised and renamed the local magnitude scale, denoted as ml or m l. The instrument as a whole is sensitive to horizontal motions, which are detected via light re. The m, scale, introduced by richter in 1935, is the antecedent of every magnitude scale in use today. But it doesnt say much about the size of the earthquake source or the total amount of energy released.