Floor tile cracks & slab foundations

I take this question to mean that if there are cracks in the floor tile are there corresponding cracks in the slab surface?  The answer is that it depends.  There are usually one of two situations that present themselves for evaluation.  I discuss each of these below:

There are one or more individual tiles that are cracked but no cracks that run from tile to tile:

In this situation, the most reasonable explanation is that there are probably no crack in the slab surface under the cracked tile.  If there is such a crack, it is almost certainly not an active crack.

There is at least one crack in the tile that runs from tile to tile:

When this is the case, there is almost always a crack in the slab surface that mirrors the crack or cracks in the floor tile.  The cracks in