Lazy copy and paste
I have a theory about the booming sounds around the US.
Groundwater overextraction, could be the reason for the sounds, as more water is pumped out of the ground and not replenished fast enough, the rock below is starting to dry out and colapse from the missing water preasure.
In the end the land will start to sink.
Land subsidence is a gradual settling or sudden sinking of the Earth's surface owing to subsurface movement of earth materials. Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence. The principal causes are aquifer-system compaction, drainage of organic soils, underground mining, hydrocompaction, natural compaction, sinkholes, and thawing permafrost (National Research Council, 1991). Three distinct processes account for most of the water-related subsidence--compaction of aquifer systems, drainage and subsequent oxidation of organic soils, and dissolution and collapse of susceptible rocks.
Long shot, but a realistic one.