Geometry.Net - Basic_E: Earthquake Measurement

Measuring Earthquakes
Seismologists use two main devices to measure an earthquake a seismograph and a The original scale was modified to measure earthquakes at any distance,
http://skywalker.cochise.edu/wellerr/students/measure-quake/paper.htm

Extractions: Physical Geology Seismologists use two main devices to measure an earthquake: a seismograph and a seismoscope. The seismograph is an instrument that measures seismic waves caused by an earthquake. The seismograph has three main devices, the Richter Magnitude Scale, the Modified Mercalli Intensity Scale, and the Moment-Magnitude Scale. The seismoscope is an instrument that measures the occurrence or the time of an occurrence of an earthquake (Inventors). Unlike other measuring devices, the seismoscope is a simple device without any technological background. The seismoscope is the oldest and most accurate instrument for measuring direction.
Index.html
Indonesia/Nicobar/Andaman Mw=9 earthquake 2004 Materials and background info . and strain and tilt measurements related to monitoring earthquakes,
http://cires.colorado.edu/~bilham/

Extractions: Earthquakes and Tectonic Plate motions Roger Bilham, University of Colorado Geology 1010 Indonesia/Nicobar/Andaman Mw=9 earthquake 2004 Materials and background info. Updated 6 May 2005. Sumatra-Andaman HTML SRL Article or (733k) pdf Article March 2005 Parkfield Earthquake 28 September 2004 Creepmeters monitored the transition from coseismic surface strain to surface fissuring and afterslip. (html article) pdf article Global urban earthquakes, Worse to come? Seism. Rev.Lett. Dec 2004 The centenary of the Kangra 1905 Earthquake [1905 Kangra geodetic slip Earthquake Hazards Near Delhi- Annotated 9.1 Mb power-point talk. Annotated pdf 3Mb. GeoHazards "Delhi Earthquake Intiative for Lifeline Buildings" 1 May 2005 University of Colorado, Boulder CO 80309-0399 USA FAX 303 492 2606 Phone 303 492 6189 email: bilham@colorado.edu Publications New NSF biaxial tiltmeters near Seattle The Sumatra/Andaman M9 earthquake was recorded by the new Shelton Tiltmeter. Data from tiltmeters near Mammoth Lakes in the Long Valley Caldera (US Geological Survey) are available subject to telemetry and power outages. Anomalous tilt near Mammoth Lakes in Long Valley 13-16 October 1998 was apparently caused by aseismic dip-slip on a graben bounding fault near the tiltmeter - the only known example of a slow normal earthquake.
Nearctica - Education - Subjects - Earthquakes
Also read about measuring the intensity of an earthquake and the future ofearthquake prediction. The San Andreas Fault. Sandra Schulz and Robert Wallace.
http://www.nearctica.com/educate/subject/equake.htm

Extractions: Subjects - Earthquakes Special Segments Butterflies of North America Conifers of North America Eastern Birds List of N.A. Insects Home Eastern Wildflowers General Topics Natural History Ecology Family Environment Evolution Home Education Home Conservation Geophysics Paleontology Commercial Organizations Return to Education - Subjects Want to find more links on earthquakes and tsunamis? Go to the EARTHQUAKE pages in the Geology segment of Nearctica GENERAL INFORMATION ON EARTHQUAKES General Earthquake Information . National Earthquake Information Center. If you want to learn about earthquakes this is certainly the place to go. This magnificent site has a wealth of information. For example there are sections on frequently asked questions, the largest earthquakes in the United States and the world, information on how earthquakes are measured, the principle faults in the United States, plate tectonics and their relationship with earthquakes,a glossary of seismology terms, and much more. There are even a couple of word search puzzles you can play with related to earthquakes and plate tectonics. Earthquakes in Southern California . Caltech Seismological Laboratory. We love this site. It contains a wealth of information about earthquakes in Southern California. It includes clickable maps of earthquake locations, a clickable map of the fault systems with detailed information on each fault. Be sure to look at some of the animations of earthquakes day by day or year by year. The site also has basic information earthquakes and how to live with them. You'll find information on making you house safe and how to go about preparing for an earthquake.
Nearctica - Geology - Earthquakes
Also read about measuring the intensity of an earthquake and the future ofearthquake prediction. Recommended. The San Andreas Fault.
http://www.nearctica.com/geology/quake/quake.htm

Extractions: Earthquakes Special Segments Butterflies of North America Conifers of North America Eastern Birds List of N.A. Insects Home Eastern Wildflowers General Topics Natural History Ecology Family Environment Evolution Home Education Home Conservation Geophysics Paleontology Commercial Organizations Return to Geology Main Page Books About Earthquakes This page contains links to general sites on seismology and earthquakes. Be sure to visit the other pages in the earthquake section of geology as well. GENERAL SEISMOLOGY SITES General Earthquake Information . National Earthquake Information Center. If you want to learn about earthquakes this is certainly the place to go. This magnificent site has a wealth of information. For example there are sections on frequently asked questions, the largest earthquakes in the United States and the world, information on how earthquakes are measured, the principle faults in the United States, plate tectonics and their relationship with earthquakes,a glossary of seismology terms, and much more. There are even a couple of word search puzzles you can play with related to earthquakes and plate tectonics. Highly recommended. Earthquakes in Southern California . Caltech Seismological Laboratory. We love this site. It contains a wealth of information about earthquakes in Southern California. It includes clickable maps of earthquake locations, a clickable map of the fault systems with detailed information on each fault. Be sure to look at some of the animations of earthquakes day by day or year by year. The site also has basic information earthquakes and how to live with them. You'll find information on making you house safe and how to go about preparing for an earthquake. Highly recommended.
FAQs On Pacific Northwest Earthquakes
The Richter magnitude of an earthquake is calculated by measuring the Intensity of an earthquake is a measure of the amount of ground shaking at a
http://www.pnsn.org/INFO_GENERAL/faq.html

Extractions: HOME Latest Quakes Volcanoes Research ... CONTACT US Frequently Asked Questions Earthquakes in Washington and Oregon Where are the major faults in the Pacific Northwest? Are there faults near Seattle and Portland? Why does the Pacific Northwest have earthquakes? How often do earthquakes occur in the Pacific Northwest? ... There seems to be a lot of activity on the Webicorders, but there are not any events listed on the "Recent Events" list. What is going on? Return to Seismology Page Q: Where are the major faults in the Pacific Northwest? A: There are many faults in the Pacific Northwest that can produce damaging earthquakes, including hard-to-identify faults that exist entirely underground and have not been identified at the earth's surface. At the same time, some mapped faults have been located that have not generated earthquakes in recent geologic time. New faults continue to be discovered as more field observations and earthquake data are collected. There are three different sources for damaging earthquakes in the Pacific Northwest. The first of these is the "Cascadia Subduction Zone", a 1000 km long thrust fault which is the convergent boundary between the Juan de Fuca and North American plates and is the most extensive fault in the Pacific Northwest area. It surfaces about 50 miles offshore along the coasts of British Columbia, Washington, Oregon and northern California. No historic earthquakes have been directly recorded from this source zone. According to recent research, an earthquake estimated to be as large as 8.0 to 9.0 occurred in this zone in January of 1700.
WA Earthquake Hazards - How Are Earthquakes Measured?
HOW ARE earthquakeS MEASURED? taken from Washington State earthquake Hazards , The intensity of an earthquake is a measure of the amount of ground
http://www.pnsn.org/INFO_GENERAL/NQT/how_are.html

Extractions: Figure 6 shows how the Richter magnitude of an earthquake is calculated by measuring the amplitude of the maximum wave motion recorded on the seismogram. The intensity of an earthquake is a measure of the amount of ground shaking at a particular site, and it is determined from reports of human reaction to shaking, damage done to structures, and other effects. The Modified Mercalli Intensity Scale ( Table 1 ) is now the scale most commonly used to rank earthquakes felt in the United States. If magnitude is compared to the power output of a radio broadcasting station, then the intensity of an earthquake is the signal strength at a particular radio receiver. In practice, an earthquake is assigned one magnitude, but it may give rise to reports of intensities at many different levels. The magnitude 6.5 April 29, 1965, Seattle-Tacoma earthquake produced intensity VII to VIII damage near its epicenter, intensity V damage 150 kilometers away, and intensity I and 11 (barely felt) 300 to 500 kilometers from the epicenter ( Figure 7 ). Although the greatest damage, and thus highest intensity, is usually near the earthquake's origin, damage to buildings depends on many factors, such as the type of construction, distance from the epicenter, and type of soil beneath the building. (See Structural Failure of Buildings, in the section titled What Causes Damage?) Therefore, maps of earthquake intensity commonly show complex patterns.
Nepalnews.com Mercantile Communications Pvt. Ltd. (News Feature September 2004)
The massive earthquake (measured 8.4 on the Richter scale) that hit in 1934 (popularlyknown as `Nabbe Saalko Bhuichalo) cost lives of over 8500 people in
http://www.nepalnews.com.np/archive/2004/dec/news_features_dec04_02.htm

Extractions: Font Problems? ... The Asia Quake: Will Nepal learn lessons? (Nepalnews Special Report) By Bhagirath Yogi As reports of unprecedented death and destruction continue to pour in from nine countries affected by the devastating undersea earthquake that hit off the Sumatra coast in Indonesia early Sunday, experts and scientists says landlocked Nepal must learn lessons from the latest natural disaster. Its a wake-up call for Nepal.
EQ Causes And Measurements
Prof. Stephen A. Nelson. earthquakes Causes and Measurements A better measureof the size of an earthquake is the amount of energy released by the
http://www.tulane.edu/~sanelson/geol204/eqcauses.htm
Earthquakes Module 5 Environmental Geology
Detecting, Locating, and Measuring earthquakes but it is not required here.)Write down how important facts about an earthquake are measured.
http://wapi.isu.edu/envgeo/EG5_earthqks/eg_mod5.htm

Extractions: by Anni Watkins E a r t h q u a k e s are probably the most frightening naturally occurring hazard encountered. Why? Earthquakes typically occur with little warning. There is no escape from an earthquake! Earthquakes have devastating effects, resulting in hundreds to thousands of deaths and injuries, and millions to billions of dollars worth of property damage. The earthquake's location, magnitude of the earthquake, surface geology, and population density are major factors contributing to earthquake damage. Earthquakes result from movement along a fault. Faults and earthquakes are cause and effect. The sense of motion on faults describes how the block move relative to each other. Faults may move along preexisting fracture or may form a new one. There are 3 basic types of faults: normal, reverse, and strike-slip. Normal and reverse faulting result in vertical slip, while strike-slip faulting results in horizontal slip. In nature, motion is seldom absolutely along one direction. There can be a combination of vertical and horizontal slip, which would make the movement along the fault oblique. Normal faults are associated with extension. A good example of normal faulting is the Basin and Range topography of the western United States. The western part of the North American plate has been pulled apart into a series of "blocks". Most Basin and Range structures result from the tilting of these blocks. A major Basin and Range fault zone is the Wasatch Fault zone, which is 220 miles long (360 kilometers) and extends from Utah into Idaho.
Richter Earthquake Scale
Richter and Mercalli earthquake Scales describing earthquake force. of theresulting earthquake damage and not actually measured on instruments.
http://www.mistupid.com/geology/richter.htm

Extractions: Intensity Description I Usually not felt, but detected by instruments. II Felt by very few people. III Felt by many, often mistaken for a passing vehicle. IV Felt by many indoors, dishes and doors disturbed. V Felt by nearly everyone. People awakened. Cracked walls, trees disturbed. VI Felt by all. Many run outdoors. Furniture moves. Slight damage occurs.
NOAA News Online (Story 2365)
NOAA SCIENTISTS ABLE TO MEASURE TSUNAMI HEIGHT FROM SPACE The massive tsunamitriggered by an undersea earthquake in the Indian Ocean literally rippled
http://www.noaanews.noaa.gov/stories2005/s2365.htm

Extractions: NOAA Magazine NOAA Home Page Previous Story Commerce Dept. NOAA SCIENTISTS ABLE TO MEASURE TSUNAMI HEIGHT FROM SPACE Jan 10, 2005 After reviewing data from four Earth-orbiting radar satellites, NOAA scientists today announced they were able to measure the height of the devastating tsunami that erupted in the Indian Ocean. The ability to make depth surveys from space may lead to improvements in the models that forecast the hazardous effects of tsunamis. (Click NOAA image for larger view of tsunami wave height as measured by satellites two hours after the event. Click here for high resolution version, which is a large file. Click here (Click NOAA image for larger view of tsunami wave height as measured by satellites two hours and five minutes after the event. Click here for high resolution version, which is a large file. Click here (Click NOAA image for larger view of tsunami wave height as measured by satellites three hours and 15 minutes after the event. Click here for high resolution version, which is a large file.
Frictional Motion Study Could Provide Tool For Earthquake Prediction
An earthquake is felt (and is measured seismically) as a sudden, rapid movement,or sliding, of tectonic plates in a frictional action, says Fineberg.
http://www.physorg.com/news1337.html

Extractions: The survey takes less than two minutes, there's nothing to identify you personally, and you won't receive any email or other sales pitches by participating. September 27, 2004 A new study on "waves (or fronts) of detachment" involved in the process of friction offers a new perspective on an old scientific puzzle and could provide a key to improving predictions of future earthquakes, say scientists at the Hebrew University of Jerusalem.
Georgia Tech: Seismic Site Characterization And Geotechnical Earthquake Hazards
and geotechnical earthquake engineering including laboratory and in situmeasurement of Structural Dynamics and earthquake Engineering recommended
http://www.pe.gatech.edu/conted/servlet/edu.gatech.conted.course.ViewCourseDetai
Earthquakes
earthquake Intensity Measure of an earthquake s destructive power (size and earthquake Magnitude - Quantitative measure of the energy released by an
http://www.geo.ua.edu/intro03/quakes.html

Extractions: Earthquakes Vibrations of the Earth caused by the sudden release of energy, usually as a result of displacement of rock along faults. An earthquake is always followed by a series of smaller earthquakes (aftershocks) which represent further adjustments of rock along the fault. Approximately 13 million people have died as the result of earthquakes during the past 4,000 years. There are currently no reliable methods for predicting when earthquakes will occur. Cause of Earthquakes Earthquakes are caused by the sudden release of energy along faults.
Recording Earthquakes
They hope that by collecting data about past earthquakes they can help predictfuture His measurement is known as the Richter magnitude; although many
http://www.chemistry.org/portal/a/c/s/1/feature_tea.html?DOC=teachers\tea_seismo
Centre For The Observation And Modelling Of Earthquakes And Tectonics
to measure strain accumulation across faults occurring between earthquakes, Wright TJ, B. Parsons, EJ Fielding, measurement of interseismic strain
http://comet.nerc.ac.uk/news_watervapour.html

Extractions: in the presence of atmospheric water vapour This project involves the following strands: A study of the strain accumulation using archived ERS SAR data across a major fault zone where the effects of atmospheric water vapour are significant. It may also be possible to use Envisat ASAR data; by the end of the project over five years of Envisat ASAR observations will be available. Use estimates of water vapour from MERIS observations in the same area to understand the ways in which atmospheric water vapour affects the interferograms, to determine the statistics of the variability that must be reduced by using multiple ERS interferograms, and to correct any Envisat ASAR interferograms used. A quantitative assessment will be made of the limitations and potential of different methods for scaling coarse-scale MERIS WV observations to the relevant length scales required for InSAR correction. Use of other atmospheric remote sensing data to understand the relationship between the variability due to atmospheric water vapour in the interferograms and weather systems passing through the area to see if there are rules of thumb that can be used in selecting interferometric pairs.
EIS: Educational Outreach Strategy Involves Students In Earthquake Hazard Resear
NASA has been making precise geodetic measurements to assess earthquake hazardassociated with the subduction zone process in Alaska since 1984.
http://www.agu.org/sci_soc/articles/sauber.html

Extractions: Home Science and Society Science for Everyone Solid Earth GEODESY AND SEISMOLOGY Educational Outreach Strategy Involves Students in Earthquake Hazard Research by J. Sauber, S. Stockman, and T. Clark, Laboratory for Terrestrial Physics, NASA's Goddard Space Flight Center, Greenbelt, Maryland NASA has been making precise geodetic measurements to assess earthquake hazard associated with the subduction zone process in Alaska since 1984. In 1995, a new strategy for making geodetic measurements was implemented that included local residents in the measurement program, and in 1997, the program was expanded to include teachers and students at five high schools. For the inhabitants of Alaska, understanding the hazards and underlying physical processes associated with earthquakes has immediate personal relevance. Large earthquakes occur yearly, great earthquakes have occurred during the lifetime of many residents, and the weekly testing of the tsunami warning system in coastal towns is a reminder of the devastation caused by earlier tsunamis generated near Alaska and serve as a cautionary note about future inundation. Fig. 1. Location of geodetic sites (open diamonds) occupied in 1993, 1995, and/or 1997, and the permanent GPS site near Fairbanks (open square). The five boxes with the high school name on the right side indicate the observation region of each school. The shaded regions (with year) indicate the rupture zones of major earthquakes in southern Alaska during this century. The predicted rate of motion of the Pacific plate relative to a fixed North American plate is given by the vector in the lower right-hand corner.
Calculating Depths Of Deep Earthquakes
The depth to very deep earthquakes is usually established by measuring thedifference in arrival time of the P and pP wave. This is something you can do
http://lasker.princeton.edu/ScienceProjects/curr/deepeq/deepeq.htm

Extractions: The depth to very deep earthquakes is usually established by measuring the difference in arrival time of the P and pP wave. This is something you can do yourself with a bit of practice. You may be able to discover the deepest earthquake known so far! The best estimate for the deepest known earthquake is 684 km deep, under the Fiji Islands in the Southwest Pacific, on June 17, 1977. How do you go about this? First learn to recognize the pP wave. It has very much the same shape as the P wave (it reflects from the Earth's surface, very much like a reflection in a mirror, before going on its journey to the seismic station). Hint: sometimes it is much easier to see the pP and P similarity when you transform the seismogram to displacement rather than velocity. This is because pP spends more time in the "syrupy" upper mantle above the earthquake, where it looses some of the high frequencies (little wiggles). We provide some selected pairs of P and pP waves from the Global Seismograph Network in the file deepP.dat
Earthquakes!
One of its flaws is its imprecision in measuring the biggest earthquakes, thosein the range of 8 or 9. Different methods of measuring magnitude have
http://www.infoplease.com/spot/earthquake1.html

Extractions: Earthquakes in residential areas, such as this 1964 one in Seward, Alaska, can cause unparalleled damage to life and property. There are thousands upon thousands of earthquakes annually, ranging on average from 18 major quakes to more than 2 million very minor ones per year (approximately 8,000 per day). On average, we can expect one exceptionally big one (with a magnitude of 8 or higher) each year.
FEMA For Kids: Young Americans Prepare: Becoming Disaster Ready
The Richter Scale is a measure of the magnitude of earthquakes. The scales usemeasurements from a seismograph an instrument used to record earthquakes
http://www.fema.gov/kids/98wdeq.htm

Extractions: Young Americans Prepare: Becoming Disaster Ready Earthquakes Introduction: While earthquakes are thought to occur largely in the Western U.S., in fact many states are vulnerable for quakes, including Kentucky, Missouri, Tennessee, Texas, even New England. Drop and cover (get on the floor, get under heavy furniture and cover your head) drills are the best hands-on activity to teach students of all ages how to prepare. Practicing in the classroom and then recommending practice at home can save lives. Earthquakes also are fascinating to study. They incorporate earth science, history, writing, art, math, geography and other school subjects. Below are some lecture materials, suggested classroom exercises, and sources of more information that you can include in your lesson plans. We hope you will use this information especially during the week that encompasses October 14, 1998, which is celebrated as World Disaster Reduction Day in this country and around the globe. The lecture information provided here is only a sample of what can be found in two excellent curriculum guides available free from FEMA. "Tremor Troops" is geared for K-6 grade and "Seismic Sleuths" is for 7th through 12th graders. See FEMA resources below for ordering information. Lecture #1: Earthquake measurement (Science, geology, geography, physics)

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

81-100 of 104 Back | 1 | 2 | 3 | 4 | 5 | 6 | Next 20