The Mysterious Exploding Floor

On Saturday night ZooDaddy and I were disturbed by some mysterious creaking noises in the other end of the house. These then developed into louder more crunchy sounds and so ZooDaddy got up to investigate. When he reached the end of the passage there was an almighty crash (I initially thought he had knocked our huge display mirror off the wall). I waited for a bit, not quite what to do, but he soon called me to come and look.
Essentially what I saw was our kitchen floor exploding in front of us. It really was the most bizarre thing! We couldn't work out what was causing it. Obviously we were scared of subsidence or shifting of the house, but there was absolutely no sign anywhere else of movement - cracks or displacement.
We took some photos and, not knowing what else to do, went back to bed.
On Sunday all seemed stable. MrTepps was initially very distressed: "Look what happened to the floor! What a mess! It's broken, the floor!" For a while he presented us with broken tiles, saying sadly, "Fix it". Thankfully, however, it didn't take him too long to get over it.
After a quiet morning (including hosting the church meeting) it all started happening again. This time ZooDaddy was ready with his phone and managed to capture it on video. Here it is.