Use the Army Corps of Engineers, Navy Sea Bees, something like that. Look at https://en.wikipedia.org/wiki/Seikan_Tunnel https://en.wikipedia.org/wiki/Seikan_Tu

Use the Army Corps of Engineers, Navy Sea Bees, something like that. Look at https://en.wikipedia.org/wiki/Seikan_Tunnel https://en.wikipedia.org/wiki/Seikan_Tunnel going between islands under the Japan Seas in an earthquake area. Think BIGGRRRR! (Aggressively so, instead of sissying around!) edit: also not to forget about 'Nuclear Tunnel Boring Machines/Subterrene' https://havacuppahemlock1.blogspot.com/2015/06/nuclear-powered-drilling-machine.html https://havacuppahemlock1.blogspot.com/2015/06/nuclear-power... cf. "Trans-Planetary Subway Systems A Burgeoning Capability by Robert M. Salter February 1978" https://www.rand.org/pubs/papers/P6092.html https://www.rand.org/pubs/papers/P6092.html