Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at that site. The slip of one block of rock over another in an earthquake releases energy that makes the ground vibrate.
That vibration pushes the adjoining piece of ground and causes it to vibrate, and thus the energy Moment magnitude, Richter scale - what are the different magnitude scales, and why are there so many? Earthquake size, as measured by the Richter Scale is a well known, but not well understood, concept.
The idea of a logarithmic earthquake magnitude scale was first developed by Charles Richter in the 's for measuring the size of earthquakes occurring in southern California using relatively high-frequency data from nearby seismograph stations What is the difference between earthquake magnitude and earthquake intensity?
What is the Modified Mercalli Intensity Scale? Magnitude scales , like the moment magnitude, measure the size of the earthquake at its source. An earthquake has one magnitude. The magnitude does not depend on where the measurement is made. Often, several slightly different magnitudes are reported for an earthquake. This happens because the relation between the seismic measurements and the How do you determine the magnitude for an earthquake that occurred prior to the creation of the magnitude scale?
For earthquakes that occurred between about when modern seismographs came into use and when Charles Richter developed the magnitude scale, people went back to the old records and compared the seismograms from those days with similar records for later earthquakes. For earthquakes prior to about , magnitudes have been estimated by Filter Total Items: 7.
Lamb, Rynn M. View Citation. Year Published: Earthquake hazards: a national threat Earthquakes are one of the most costly natural hazards faced by the Nation, posing a significant risk to 75 million Americans in 39 States.
Year Published: Taking the Earth's pulse During the past 35 years, scientists have developed a vast network of seismometers that record earthquakes, volcanic eruptions, and nuclear explosions throughout the world.
Woodward, Robert L. Filter Total Items: 3. Date published: May 25, Date published: January 23, Date published: September 24, Filter Total Items: List Grid. October 27, August 31, March 17, Attribution: Earthquake Hazards Program. June 3, A seismometer deployed near the epicenter of the Greeley earthquake in November 30, A seismograph reading.
Modern digital strong motion recorders are now replacing analog photographic paper recorders, and some have the option for continuous telemetry. To completely characterize the earth's movement, the motion must be measured in three perpendicular directions. Consequently, seismographs often employ three sensors, recording in each of the north-south, east-west and vertical up and down directions. Skip to main content Skip to "About this site". How we record earthquakes Seismographs During an earthquake, vibrations caused by the breakage of rock along a fault zone radiate outward from the point of rupture.
How Seismometers Work To determine the motion of the earth during an earthquake, ground motion must be measured against something that remains relatively fixed i. What is shown on a Seismogram? What do seismic waves look like? Hodgson, John. Earthquakes and Earth Structure. New Jersey, Prentice Hall, , p. New Zealand Earthquakes. Major Faults in New Zealand. Monitoring Earthquakes. Seismic Activity. What are seismic waves?
What are Seismographs? Where are NZ's seismographs located? Ground Deformation.
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