Will the tunnel be QUAKE PROOF?
Quake proof? Not if you want it near the people that want it.
My first thought too. Uh, how CLOSE will this tunnel be to an active FAULT line???
Tunnels, when designed properly, are known to be one of the safest places to be during an earthquake. From a structural safety standpoint, the tunnel moves uniformly with the ground, in contrast to surface structures. Additionally, a large amount of earthquake damage is caused by falling debris, which does not apply inside tunnels. Some examples:
1994 Northridge Earthquake: no damage to LA Subway tunnels
1989 Loma Prieta (Northern California) Earthquake: no damage to tunnels, which were then used to transport rescue personnel
1985 Mexico City Earthquake: no damage to tunnels, which were then used to transport rescue personnel