Technically, the Richter scale is not currently used for anything.
It's the Moment Magnitude scale I'm sure they're referring to in the press release.
http://wwwneic.cr.usgs.gov/neis/eqlists/eqstats.html
And the article isn't incorrect, just unclear. a 9.3 has twice the ground motion of a 9.0, but does in fact release THREE times the energy of a 9.0, as you can see from the link above.
Well, except for confusing the public.