  Motivated by the short-baseline neutrino oscillation anomalies that suggest
the existence of sterile neutrinos at the eV scale, we construct a scenario of
a seesaw mechanism for 3+1 light neutrinos implemented by warped
compactification of an extra dimension. As the seesaw mechanism necessitates at
least two right-handed neutrinos at mass scales much larger than eV,
incorporating an eV-scale sterile neutrino into a seesaw entails large mass
hierarchies among the singlet neutrinos. We show that such hierarchies can be
naturally explained by moderate fluctuations of the five-dimensional fermion
mass parameters.
