ML, Mw, Md
Posted by John Vidale on July 28, 2006 at 07:28:37:

Do you mean version L as in the magnitude is given as an ML? Exactly which magnitude scale is used shouldn't matter much. As the glossary summarized, magnitude can be measured in a lot of ways, which are designed to match.

ML uses the amplitude as recorded through an instrument (a Wood-Anderson one) with a particular response, Mw uses the amplitude of the ground displacement (or as long-period a signal as can be measured), Md measures how long it takes for the coda to return to background levels.

So to first order, the scale used doesn't matter, but for small quakes, the more important question is whether the magnitude has or hasn't yet been reviewed by a person to be sure the quake exists and the numbers are sensible.


Follow Ups:
     ● Re: ML, Mw, Md - Cathryn  13:42:14 - 7/28/2006  (39676)  (0)