8.0
Richter Scale
the rigter scale
Richter scale is used to measure earthquakes magnitude Shake intensity is measured on the Mercalli scale
sizemograph
The moment magnitude scale is used to measure the magnitude of large earthquakes. The Richter scale is still used to make an initial estimate of the magnitude of larger earthquakes and to measure small and moderate ones (those with a magnitude below 7).
Large earthquakes (magnitudes greater than 8) are measured using the MMS (moment magnitude) scale. Small and moderate strength earthquakes (those with magnitudes less than 7) are measured using the Richter magnitude scale and earthquakes with magnitudes between 7 and 8 are measured using the Surface Wave magnitude scale.
The Richter scale was originally developed to measure the strength or magnitude of moderate earthquakes (magnitudes less than 7). The surface wave magnitude scale was then developed by Richter and Guttenburg to allow larger earthquake magnitudes to be measured (up to 8). To measure large earthquakes the moment magnitude scale must be used. To measure the severity of earthquakes, the Modified Mercalli intensity scale is used in the US and the Macroseismic scale is used in Europe.
One statement you could write is that "Earthquakes of higher magnitudes are much rarer than those of lower magnitudes". The magnitude of earthquakes is a logarithmic scale, so a magnitude of 8 is TEN TIMES more powerful than a magnitude 7. This is why earthquakes of higher magnitudes are so much rarer than those of lower magnitudes.
Richter scale
Earthquakes.
The Richter scale
You can measure earthquakes on the Moment magnitude scale or the Richter scale
Richter Scale
The moment magnitude scale is used by seismologists to measure the amount of energy released by large earthquakes (those greater than magnitude 8.0). For smaller earthquakes (those with magnitudes less than 7.0 and with epicentres less than 650 km from a seismometer station may be used) the method devised by Richter (the Richter magnitude scale) may be used to estimate the magnitude. The surface wave magnitude scale may be used for earthquakes with magnitudes up to 8.0 (devised by Richter and Gutenberg to extend the utility of the Richter scale.) Richter magnitudes are generally easier to derive than moment magnitudes being based on direct seismometer measurements, whereas the moment magnitude is a more4 fundamental measurement of magnitude being based on the rock mass strength around the fault, the amplitude of fault movement and the cross sectional area of that portion of the fault that moved. However this is more difficult to measure. As such it is common for initial reports to be in Richter magnitudes and more detailed letter magnitudes to be reported as moment magnitudes.
magnitude
the rictor scale
An earthquakes intensity