Issues of Stability and Ground Motion in ILC

Stability of International Linear Collider is determined by the stability of the site, additional noises of beamline component, energy and kicker jitter, and performance of train-to-train and intratrain feedback. Stability goals in terms of the beam jitter at the end of the linac, in BDS and at the IP are discussed in this paper, and translated to stability goals for the site and for component jitter. Present status of stability studies is reviewed and feasibility of achieving the stability goals is discussed.