Richter scale: the original measure of earthquake magnitude
At the beginning of the twentieth century, very little was known … See more

Moment magnitude is now the most common measure of earthquake size for medium to large earthquake magnitudes, but in practice, … See more

Seismic moment is not a direct measure of energy changes during an earthquake. The relations between seismic moment and the energies involved in an earthquake depend … See more

Various ways of determining moment magnitude have been developed, and several subtypes of the Mw  scale can be used to indicate the basis used.
• Mwb – Based on moment tensor inversion of long-period (~10 – 100 s) body-waves. See more

The symbol for the moment magnitude scale is Mw , with the subscript "w" meaning mechanical work accomplished. The moment magnitude Mw  is a dimensionless value defined by Hiroo Kanamori as See more

Assuming the values of σ̄/μ are the same for all earthquakes, one can consider Mw  as a measure of the potential energy change ΔW caused by earthquakes. Similarly, if one … See more

• Earthquake engineering
• Lists of earthquakes
• Seismic magnitude scales See more