Mascon- Mass concentration. We.. THEY left a bunch on the moon, too.


The gravity generator was set to implode, which causes a small shere of neutonium to be produced. It would sink into the earth ( aftre collapsing the building due to its gravitational effect.

BTW, the same generator can be used to reduce gravity, making it comfortable for those used to a lower gravity. Just suspend it ABOVE the area to be affected- it counterbalances a part of the Earth's gravity.