Settlement of 55cm occurred by Iwate-Miyagi inland earthquake in the crest of Ishibuchi dam which is the rock-fill dam in the suburbs of the seismic center in 2008 and analyzes the dynamic response of the Ishibuchi dam in this study and a comparison reproduces residual settlement quantity calculated by the residual deformation analysis by the Watanabe-Baba method which supposed and does arc sliding with the proof of the analytical method. And I was able to prove that the applicability of the residual deformation method was high, and I included small density and strength by the lack of compaction. It is necessary to know the relation between earthquake and the crest settlement by the earthquake, if crest settlement will lead to be equal to the differences between crest and H.W.L. when Ishibuchi dam collapsed.