Edo (now Tokyo) area suffered serious damage from a great earthquake in 1855, Ansei era. The earthquake is conceived to be essencially an inland earthquake, although the crustal movement might be extended to the bottom of Tokyo Bay. Whether or not a tsunami was generated by the earthquake is investigated basing on historical documents. Although, no tsunami damage was reported, it seems likely that some phenomena associated with a tsunami, which was too small to be observed obviously, took place. Numerical experiments on three fault models, that are supposed on the upper surface of the subducted Philippine sea plate, are made in order to see possible tsunami generation in Tokyo Bay. Maximum double amplitudes of computed tsunamis amount to 10 to 20cm which are in harmony with historical documents. It may be one of the reasonable interpretations for the source model of the earthquake, therefore, that the Ansei Edo earthquake occurred on the plate boundary. Water oscillations induced by the seismic acceleration in a tank or a pool are numerically investigated. It becomes apparent that such water oscillation is largely controlled by the resonance in the reservoir.