Energy Magnitude ( Me ). The energy magnitude, Me, is computed from the radiated energy using the Choy and Boatwright (1995) formula (eq. 6):
Me = 2/3 log ES - 2.9 where energy is in Newton-meters.
The relationship of Me to MW. Although Me and MW are magnitudes that describe the size of an earthquake, they are not equivalent. Me, being derived from velocity power spectra, is a measure of seismic potential for damage to anthropogenic structures. MW, being derived from the low-frequency asymptote of displacement spectra, is physically related to the final static displacement of an earthquake. Because they measure different physical properties of an earthquake, there is no a priori reason that they should numerically equal for any given seismic event. The energy magnitude, Me, is an essential complement to moment magnitude, MW, for describing the size and affect of an earthquake rather than an alternative.
Starting with the November 1986 Monthly Listing, the NEIC has published estimates of radiated energy computed directly from broadband body waves. Me has been published routinely beginning with the July 1995 Monthly Listing.
