If the termites could be living ~30m down...pressure at that depth, just from the weight of the overlying soil, is already about what you'd experience under a 300m-tall skyscraper. So suitable crushing equipment might be rather large and expensive. A violent-enough pressure wave would require a very large explosion...let's just say that senior political leaders would have to sign off, and those folks would smell too much potential for career-ending scandal and ridicule to do so.