We are on a complex of ten, and recently ( the last three years )six of our apartments have all experienced it... and with us it was our lounge tiles in 2010 and then our terrace tiles in 2012
We should have gone through our insurance but as we were out there on both occasions and insurance companies being too long winded .. we paid for both ourselves £1000.00
Many explanations have been kicked around... 1 sudden drop in temperature 2 tremors 3 inadequate and poor adhesive used ( hanel homes ) 4 vibrations of workmen drilling and hammering whilst we were having alteration work on the second occasion... but we could never prove this, and its a very `grey` area.. Do make sure you get a very good trades person to re do the whole area ( its impossible to patch just the affected area, unfortunately the whole area will need doing ) vacate all your furniture even picture frames etc as its extremely dusty for days after
hence the need for a reliable good CLEAN workman.
Doesnt happen on ground floor apartments it seems... all of us it happened to it was on the `first floor`
good luck !!!