The American island of Guam is getting bomb proof shelters for aircraft, fuel and ammo supplies and vital equipment. Apparently believing that China and North Korea could, and under the right conditions, would, fire ballistic missiles, using conventional (non-nuclear) warheads, the concrete protection is being discreetly constructed on military bases. This hardening also provides protection against typhoons (Pacific hurricanes) and less frequent earthquakes. This is all part of a larger construction effort. This is because the United States is in the process of moving 8,000 marines from Okinawa to Guam, which means new facilities to house these troops and their equipment. Existing facilities are also being refurbished and expanded at great expense (over $8 billion), a project that will continue for another three years.
In addition, the air defenses Guam are also being improved. There will now be three different air defense systems.
THAAD, Patriot PAC-3, and SLAMRAAM, to be specific, for a layered defense against ballistic missiles, cruise missiles, and aircraft.