5.6 equates to kilotons of energy per UCLA.
http://www.english.ucla.edu/all-faculty/335-kelly-kiloton-index-of-earthquake-moment-magnitudes
Not necessarily an actual yield though , I guess.
Do the tables reflect the cubing of the force of an actual explosion? For example the table gives 90kt for 5.3 (which I believe is what they’re calling it now). That works out to 22.5kt. That’s going to be close to what the Russians calculated before, based on 5.1 figures from a previous test by NK this year. There are other factors, I guess, plus the usual margin or error. A respectable nuke by anyone’s standard, and capable of killing hundreds of thousands.