No, assert(0) is correct: the total energy of a quake varies as the 3/2 power of the seismic moment. Both the Richter and Moment magnitude scales are based around the base-10 logarithm of the seismic moment, but that isn't the same as the total released energy of the quake.
By the way, I noticed that this fact is mentioned in the second paragraph of the very link that you cited. Did you perhaps stop reading after the first?
It is much easier to suggest solutions when you know nothing about the problem.