%0 Journal Article %T Irreducibility and p-adic monodromies on the Siegel moduli spaces %A Chia-Fu Yu %J Mathematics %D 2006 %I arXiv %X We generalize the surjectivity result of the $p$-adic monodromy for the ordinary locus of a Siegel moduli space by Faltings and Chai (independently by Ekedahl) to that for any $p$-rank stratum. We discuss irreducibility and connectedness of some $p$-rank strata of the moduli spaces with parahoric level structure. Finer results are obtained on the Siegel 3-fold with Iwahori level structure. %U http://arxiv.org/abs/math/0612839v3