Earthquake Magnitudes Explained

Richter and presented in his landmark 1935 paper where he called it the magnitude scale.

Earthquake magnitudes explained. Seismographs started being used in around 1890 and as a result for earthquakes between 1890 and 1935 when the richter scale was introduced scientists can go back to the historical seismograph records and determine the richter scale. The richter scale also called the richter magnitude scale or richter s magnitude scale is a measure of the strength of earthquakes developed by charles f. But prior to seismographs magnitudes have to be estimated.

Looking at earthquake history. Video on earthquake magnitudes moment magnitude explained. The magnitude of an earthquake is calculated by using the richter scale formula which is mentioned and explained in brief in the following.

Estimated number each year. In fact the national earthquake information center locates about 12 000 14 000 earthquakes each year. Earthquakes with very large magnitudes and occurring deep beneath the oceanic crust deep focus earthquakes might not be even felt by us on the surface regions.

This was later revised and renamed the local magnitude scale denoted as ml or m l. Often felt but. Instant earthquake magnitudes seem as routine an achievement as reporting the temperature but they re the fruit of generations of scientific work.

By robert coontz mar. Why earthquakes are hard to measure. Magnitude measures the energy released at the earthquake s source while intensity measures the strength of shaking.

Usually not felt but can be recorded by seismograph. The formulas differ but they yield the same numbers for moderate earthquakes. Originally earthquake magnitudes were based on the amplitude of ground motion displacement as measured by a standard seismograph.

This fact sheet illustrates information on the frequency of earthquakes of various magnitudes along with details on the effects of earthquakes and the equivalent energy release. The types and nature of these waves are described in the section seismic waves because the size of earthquakes varies enormously it is necessary for purposes of comparison to compress the range of wave amplitudes. Earthquake magnitude is a measure of the size or amplitude of the seismic waves generated by an earthquake source and recorded by seismographs.

The best known of these is the richter magnitude which was defined for local earthquakes in southern california. These are explained in earthquakes in a nutshell.