That is my guess too. They are using nuclear warhead implosion technology, precision detonators and shaped charge high explosives to generate the right sort of shockwaves. It might be possible but it will certainly be much more inclined to generate earthquakes than hydraulics.
It probably is crazy and not cost effective but it is a fairly safe way of disposing of these redundant ex-nuclear bomb components (and giving the ex bomb makers something interesting to do that isn't bombs).