I generally love this show. I've watched nearly every single episode, made so far, but right from the opening scene this felt familiar. I seemed to recall Dick Van Dyke having a very similar story, and it only took a quick search to find it, (I used a search engine for Diagnosis Murder earthquake) and found S1 Ep22 "Shaker" (produced 8 years before this episode). Both the victim on DM & the victim for this episode were killed during, but not by, the earthquake and then the earthquake is used as a way of making it look like an accident. For both victims it was meant to look like the armoire crushed them. Both Dr. Sloan and Monk had their suspicions aroused by the same clues (rest of the wall had paintings with minimal disruption and the back of the armoire had no dust - which would be expected from dust settling after it fell).
There are the usual Monkisms that make this episode worth watching but I was surprised that the writers would use the same scene, especially when there are a lot more ways that people could be murdered with an earthquake going on.
The ending of this episode is more action packed than any DM episode but it would have deserved a much higher rating if it hadn't been for the blatant steal.