How is richter scale used

Back to login. Already have an account? Login here. Earthquake prediction includes not only the place and the time, but also the magnitude of the tremor. Scientists know that earthquakes occur along fault lines, so this makes it possible to predict the places where they will occur. The size of the fault lines also makes it possible to have a rough idea about the intensity of earthquakes that will occur in specific areas.

However, predicting the times these events might occur has not been possible to date. Another factor that contributes to the exact location of earthquakes is the way that energy tends to travels along a fault line, which can cause the overall size of an earthquake to be very large if the stress triggers tectonic plate movement along a long expanse of a fault line. The Richter scale was developed in the s and is most effective for large-scale earthquakes that are of moderate intensity.

The Richter scale measures the maximum amplitude of seismic waves as they reach seismographs. This scale is expressed with a logarithmic scale. Thus, an earthquake measuring 7. Very large earthquakes that measure more than 7. For this reason, scientists now utilize more precise and advanced measurement methods. It is measured using a machine called a seismometer which produces a seismograph. A Richter scale is normally numbered , though there is no upper limit.

It is logarithmic which means, for example, that an earthquake measuring magnitude 5 is ten times more powerful than an earthquake measuring 4. Today, earthquakes and fault motion are inextricably linked in the minds of seismologists--so much so that upon hearing that an earthquake has occurred, we immediately ask about the fault that caused it. Richter's focus, in contrast, was on the ground vibration itself, which he could easily monitor using seismometers at the California Institute of Technology Caltech.

To Richter, a high-magnitude earthquake was one with strong ground vibration. Thus, for the Richter scale no direct connection is made to any of the properties of the causative fault. Richter's scale was modeled on the stellar magnitude scale used by astronomers, which quantifies the amount of light emitted by stars their luminosity. A star's luminosity is based on telescopic observations of its brightness that are corrected for the telescope's magnification and for the star's distance from Earth.

But because luminosity varies over many factors of ten Betelgeuse is 50, times more luminous than Alpha Centauri, for example , astronomers calculate a logarithm of the luminosity to produce the stellar magnitude: an easy-to-remember single-digit number. Richter substituted measurements of the amount of ground vibration, as measured by a seismograph, for measurements of luminosity.

Note that in both cases the sense of strength is quite abstract: stellar magnitude is not a measure of the physical size of a star as might be quantified by its diameter , but rather of the amount of light that the star emits. Seismic magnitude is not a measure of the physical size of the earthquake fault as might be quantified by its area or its slip but rather of the amount of vibration that it emits.

In Richter's initial formulation, an earthquake kilometers away that caused a one-millimeter amplitude signal on the Caltech seismometer's paper recorder was arbitrarily defined to be magnitude 3. The magnification of Richter's seismometer was about 2,, so one millimeter on the paper record corresponds to about 0.

An earthquake at the same distance that produced a millimeter amplitude recording was designated magnitude 4, a millimeter amplitude was magnitude 5, and so forth.

Richter then went on to devise correction tables that allowed magnitudes to be calculated regardless of the actual distance of the earthquake from the seismometer. The appeal of the Richter magnitude scale is twofold.

First, an earthquake is summarized by an easy-to-remember and easy-to-interpret single-digit number.