Correct me if I'm wrong but sea mines are really a container of dynamite(?) with a detonation mechanism. It operates on the simple principle that you cannot compress a liquid whereas that uncompressable (or is it INcompressable?) liquid has got to go somewhere and when it does, will easily break steel plates open because it acts like a impinging hydraulic system as opposed to an expansive hydraulic system.

I would imagine that a sea mine used on land would use a similar fuze system. After all, hitting land will have the same effect as hitting water......, surface tension and all that physics stuff. Interesting.........