What does a Richter scale measure on an earthquake?

Answer 1

RICHTER SCALEThe Richter scale (known as the local magnitude scale to seismologists) was originally developed to measure small to moderate magnitude earthquakes in Southern California by Charles Richter and Beno Gutenberg. The numerical levels indicate the energy released by a particular quake.

The numerical value is obtained from the logarithm of the maximum amplitude of seismic waves as recorded on a seismometer. This value is then scaled to account for the distance from the epicentre of the earthquake to the seismometer so as to allow the value to be correlated with the local magnitude readings from other seismometers in differing locations (as seismic waves lose their energy as they propagate through the earth so if this correction was not made, then different seismometer stations at different distances would give differing Richter magnitudes for the same earthquake). The Richter magnitude measurement produced by this methodology in theory has no limit and may be positive or negative.

As stated above, the Richter scale itself is a logarithmic mathematical formula which is calibrated so that a ten fold increase in amplitude relates to a single whole number increase on the scale (e.g. an earthquake with a Richter magnitude of 5 has seismic waves with a maximum amplitude 10 times larger than those for a magnitude 4). It has a number of practical limitations, in that it is poor at recording earthquakes with magnitudes greater than 7 and at distances greater than 650 km from a seismometer.

The equation for calculating the Richter magnitude (MR) is shown below:

MR = (Log10A) - (Log10A0)

Where

A = maximum zero to peak amplitude of seismic wave (mm) recorded.

A0 = Empirical function derived from the distance from seismometer station to earthquake epicentre

Log10A0 From 0 to 200 km distance:

Log10A0 = 0.15 - 1.6 log(distance in km)

Between 200 and 600 km distance by:

Log10A0 = 3.38 - 3.0 log(distance in km)

Due to the limitations described above (distance and maximum size of measurable earthquake), it has since been replaced by the Moment Magnitude Scale in the measurement of large earthquakes - for information on this, please see the related question.
the richter scale reads the magnitude of earthquake.

Answer 2

Low and moderate magnitude earthquakes are measured on the Richter scale (those with magnitudes lower than 7.0).

Earthquake magnitude is a way of measuring the amount of energy released when an earthquake occurs.

Earthquakes with magnitudes higher than this (from 7 to 8) are measured using the body or surface wave magnitude scales and very large earthquakes (magnitude 8 and above) are measured using the moment magnitude scale.

Answer 3

The Richter magnitude scale allows us to compare estimates of the energy released by an earthquake.

An earthquake sends out compression waves from its epicentre. The more intense the earthquake, the bigger the amplitude of these waves. The Richter scale measures the amplitude of the waves, but not in a linear way. Instead, it measures the logarithm of the amplitude. This means that an earthquake of magnitude 7 has waves that are 10 times smaller than an earthquake of magnitude 8 - which is the largest quake that can be measured in this way. A magnitude 0 quake is so tiny that you could never possibly feel it.

The amplitude of the wave is quite closely related to the energy released, so that a magnitude 8 earthquake is 32 times as powerful as a magnitude 7, which is in turn 32 times as powerful as a 6, and so on.

Answer 4

It measures the magnitude, or how powerful the earthquake was. The Moment Magnitude scale measures the same thing but is more accurate because it measures during the earthquake.

Answer 5

it describes the magnitude of an earthquake ;)

Answer 6

The Richter scale measures the magnitude of an earthquake.

Answer 7

It is used to compare the force of earthquakes.