We use the moduli space of stable curves to determine the stable (in the sense of Koll\'{a}r-Shepherd-Barron) degenerations of surfaces isogenous to a product of stable curves. A recent family of examples of Catanese show that the moduli space of such smooth surfaces may have two components. The main result of this note is that these components do not meet in the stable compactification. To the best of my knowledge this gives the first example of a moduli space of stable surfaces with multiple connected components parameterizing diffeomorphic smooth surfaces. Comments are appreciated.
On the properness of the moduli space of stable surfaces
A finite group acting on the moduli space of K3 surfaces
Poincare polynomial of moduli spaces of framed sheaves on (stacky) Hirzebruch surfaces
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