41. The Richter Scale - Measuring Earthquake Magnitudes - Math Central The Indian Ocean Earthquake that struck the coast of Indonesia in 2004 was registered as a 9.0 magnitude earthquake. Magnitude is a measurement of the energy released from an http://mathcentral.uregina.ca/beyond/articles/earthquakes/richter.html

Math Central - mathcentral.uregina.ca Math Beyond School return to top The Richter Scale - Measuring Earthquake Magnitudes The Indian Ocean Earthquake that struck the coast of Indonesia in 2004 was registered as a 9.0 magnitude earthquake. Magnitude is a measurement of the energy released from an earthquake and is measured on a Richter scale, usually with a reading between 2 and 9. Earthquakes of magnitude 8.0 or greater are very rare and can completely destroy anything near the epicenter. The Richter scale measurements are logarithmic base 10, which means that an earthquake of magnitude 9.0 would be 10 times as strong as an earthquake of magnitude 8.0. Similarly, an earthquake of magnitude 9.0 would be 10 times as powerful as an earthquake that measured 5.0. Using the distance from the S-P interval time and the maximum amplitude, both of which are recorded on a seismograph, experts can use the base 10 logarithms to find the magnitude of the earthquake. The Richter scale is based on a standard measurement: an earthquake that can be felt 100km away with amplitude of 1mm is given a magnitude measurement of 3.0. This is the base measurement and all other measurements of magnitude are made to this reference. As a result, an earthquake that is 100km away, but has an amplitude measurement of 10mm would measure 4.0. The following graph shows this relationship and outlines the base reference standard at magnitude 3.0. Image reproduced with permission of Geology Labs Online A straight line is drawn from the distance measurement to the amplitude measurement of the three seismographs. The three lines should all meet at a single point on the magnitude scale in the middle, giving a magnitude reading for the earthquake.

42. Page 1 -- Measuring Earthquakes Measuring Earthquakes The tricks and tools of seismology How do scientists measure earthquakes? If you've lived in southern California or some other seismically active area for any http://www.data.scec.org/Module/sec3pg01.html

Measuring Earthquakes The tricks and tools of seismology "How do scientists measure earthquakes?" If you've lived in southern California or some other seismically active area for any length of time, you've probably seen or heard some kind of earthquake report. Whether in the newspaper, on the radio, on television, or online, the details of an earthquake report are generally the same: a date, a time, a location, and a magnitude. If the earthquake was large enough, the report may include a description of damage caused by the earthquake, or of the size of the area over which it was felt. But for even the smallest of tremors, you will always see a time, a location, and a magnitude. How are these values are determined? What physical characteristic does each represent? What kinds of instruments and calculations are involved, and how were these techniques developed? These are the questions we'll address in this section of the module. To start investigating those answers, put yourself in the place of the earliest seismologists actually, in the place of those who pondered the signficance and origin of earthquakes before the field of seismology even came into existence. If you were going to attempt to measure earthquakes "from scratch", how would you start? What do you think is the most easily measurable aspect or effect of any earthquake?

43. Earthquake Measurement Scales - Free Online Library Free Online Library List of articles about Earthquake measurement scales http://www.thefreelibrary.com/Earthquake measurement scales-s1597278

CacheBuster('') Printer Friendly 18,416,975 articles and books Periodicals Literature Keyword Title Author Topic Member login User name Password Remember me Join us Forgot password? Submit articles free The Free Library Browse Earthquake measurement scales topic Subtopics Usage Articles out of article(s) Title Author Type Date Words Comparison the proposed probabilistic-based time-history and the traditional PSHA approach. Nicknam, A. Apr 1, 2009 Reliability-based earthquake design of jacket-type offshore platforms considering pile-soil-structure interaction. ... Asgarian, Behrouz; Agheshlui, Hossein Report Apr 1, 2009 A comparison of two regional seismic damage estimation methodologies. Onur, Tuna; Ventura, Carlos E.; Finn, W.D. Liam Nov 1, 2006 Publications by Name Publications by Date Authors Literature A-D E-O P-T U-Z ... Submit articles

44. IEEE Xplore - The Development Of A Seafloor Earthquake Measurement Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options. http://www.ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1151069&isnumber=25

45. Facts About Accelerometer: Earthquake Measurement, As Discussed In Earthquake (g Facts about accelerometer earthquake measurement, Seismographs are used to measure ground motion in both earthquakes and microseisms (small oscillations described below). Most of http://www.britannica.com/facts/5/105416/accelerometer-as-discussed-in-earthquak

document.write(''); Search Site: Advanced Search With all of these words With the exact phrase With any of these words Without these words Home SHOP BROWSE BLOG ... HELP Username: Password: Remember me Forgot your password? Help Email " is the e-mail address you used when you registered. Password " is case sensitive. If you need additional assistance, please contact customer support Enter the e-mail address you used when enrolling for Britannica Premium Service and we will e-mail your password to you. FEEDBACK Did you know... Facts about accelerometer: earthquake measurement, as discussed in earthquake (geology): Seismographs and accelerometers Seismographs are used to measure ground motion in both earthquakes and microseisms (small oscillations described below). Most of these instruments are of the pendulum type. Early mechanical seismographs had a pendulum of large mass (up to several tons) and produced seismograms by scratching a line on smoked paper on a rotating drum. In later instruments, seismograms were recorded by means of a... Related Topics acceleration (physics) accelerometer (instrument) machine measurement ... MORE...

46. SOME OBSERVATIONS ON STRONG-MOTION EARTHQUAKE MEASUREMENT USING A DIGITAL ACCELE Authors WILFRED D. IWAN, MICHAEL A. MOSER, CHIAYEN PENG. Citations 28 http://academic.research.microsoft.com/Paper/12901049.aspx

var SiteRoot = 'http://academic.research.microsoft.com'; SHARE Author Conference Journal Year Look for results that meet for the following criteria: since equal to before Publication SOME OBSERVATIONS ON STRONG-MOTION EARTHQUAKE MEASUREMENT USING A DIGI... Edit SOME OBSERVATIONS ON STRONG-MOTION EARTHQUAKE MEASUREMENT USING A DIGITAL ACCELEROGRAPH Citations: 28 WILFRED D. IWAN MICHAEL A. MOSER CHIA-YEN PENG This paper presents results of a study of some of the characteristics of a PDR-1 digital strong-motion accelerograph. Results are presented for laboratory tests of the background noise level of the instrument, and these results are compared with previously reported observations for optical instruments. Noise levels for the digital instrument are found to be one or two orders of magnitude lower than for an analog optimal instrument. The paper discusses determination of displacement from acceleration data, and results of laboratory tests are presented. An instrument anomaly in the FBA-13 transducer is identified, a simple data correction algorithm proposed, and examples given. The paper also presents detailed results of a comparison of earthquake records obtained from side-by- side digital and optical analog instruments during an aftershock of the 1983 Coalinga earthquake. View or Download The following links allow you to view and download full papers. These links are maintained by other sources not affiliated with Microsoft Academic Search.

47. Earthquake Measurement Scales: Usage - Free Online Library Free Online Library List of articles about Usage in Earthquake measurement scales category http://www.thefreelibrary.com/Usage-s1597279

CacheBuster('') Printer Friendly 18,416,975 articles and books Periodicals Literature Keyword Title Author Topic Member login User name Password Remember me Join us Forgot password? Submit articles free The Free Library ... Earthquake measurement scales Browse Earthquake measurement scales topic Usage subtopic Articles out of article(s) Title Author Type Date Words Comparison the proposed probabilistic-based time-history and the traditional PSHA approach. Nicknam, A. Apr 1, 2009 Reliability-based earthquake design of jacket-type offshore platforms considering pile-soil-structure interaction. ... Asgarian, Behrouz; Agheshlui, Hossein Report Apr 1, 2009 A comparison of two regional seismic damage estimation methodologies. Onur, Tuna; Ventura, Carlos E.; Finn, W.D. Liam Nov 1, 2006 Publications by Name Publications by Date Authors Literature A-D E-O P-T U-Z ... Submit articles

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