Iran is prone to earthquakes, would an earthquake bomb do more damage than that?

Even if it just damages the centrifuges, as far as I see it, it would just delay their enrichment process, severely less than total destruction of their underground base.

Yes that's basically my point. They recalibrate, tighten the pipes, and flush the contamination back out of the chain. 6 to 8 weeks/days/whatever later it's back in cycle.