We have an LG refrigerator that makes a very loud popping noise every now and then.

Started happening about two years ago. Sounds similar to ' water hammer ', a very loud and brief pop. Keep thinking it will fail, probably will and hope it's the compressor and within the 10 year compressor warranty.

Also, at our previous home with a poured concrete slab, we experienced a single loud pop. Turned out the new 400 sq ft addition had settled to the north in one quick movement. Broke the old slab about 10 feet from the old north edge the full width of the slab. The west brick wall cracked from top to bottom and had about a 3/4" gap at the top. Interior porcelain tile cracked leaving a very sharp edge.

Regrettably the older concrete contractor with 30 years of experience didn't do proper footings for the disturbed clay soil beneath the new addition.