In this paper, we will prove that the sheaf of
-adic
vanishing cycles on a regular log smooth family is generated by
Milnor symbols, assuming that the base dvr contains a primitive
-th
root of unity. Our result generalizes the surjectivity results of Bloch and Kato (Inst.Hautes Études Sci. Publ. Math. 63 (1986), 107–152) and Hyodo (Invent. Math. 91:3
(1988), 543–557) to a regular log smooth case.