Indeterminacy of period map for hypersurfaces

I will discuss the indeterminacy locus of the period map from the moduli space of hypersurfaces to the period domain and its compactifications. In the case of quartic K3 surfaces, the result verifies the expectation of Laza and O’Grady that the period map from the GIT compactification is regular precisely on the semi-log canonical locus.