Moment Magnitude Scale (MMS) to Describe Energy Release During an Earthquake

 

If the seismic moment is known in dyne•centimeters:

 

MMS =

= (0.667 * LOG10(moment in dyne•cm)) - 10.7

 

where:

• The seismic moment values are very, very large.

• A dyne•centimeter is 0.0000001 Newton•meter (10^(-7))

 

When comparing 2 earthquakes, the difference in energy between the 2 is:

 

energy in MMS2 vs MMS1 =

= 10^((1.5 * MMS2) - (1.5 * (MMS)))

 

Limitations:

• The MMS is better than the Richter scale for describing large earthquakes. The MMS and Richer scale are comparable for moderate earthquakes.

• The MMS has problems with small earthquakes and is not used for earthquakes with a magnitude < 3.5 RS.