Typical responses here are; failure to compact, overwatering, miss placed downspouts, broken sprinkler lines and a breakdown of organic material.
Concrete can settle for numerous reasons. Some of these are: The ground beneath it is not tamped properly and this allows the earth to move, shift and settle. This in turn makes the concrete settle and crack.
Improper preparation is largely to blame for the settling concrete. Make sure you have the right information before starting and/or hire the right contractor.
Subslab movement or surface weight beyond design capacity. The former can be caused by Ice, erosion, rotten trees, a leak, and the list goes on. The latter usually relates to large heavy weight on an area not made for it. Like a beam resting on a 4" slab instead of a footer. -Josh
Concrete can settle for many reasons but mostly is improper preparation .The ground is not compacted well (or not in all) no gravel underneath concrete.
Overload on concrete can cause concrete to settle or crack (like support posts or similar )
Some cases need drainage or water flowing underneath concrete which will wash soil and cause concrete to settle.