In order to contribute to the further advancement of seismic safety evaluation and the design of dams, the Japan Commission on Large Dams released databases of earthquake recordings on dams in 1978, in 2002 and updated it in 2014. The study will mainly focus on records on two concrete dams: Tagokura gravity-dam and Kurobe arch-dam with recording devices located in the dam and also in the foundation. For each dam, a minimum set of 5 earthquake records from Magnitude 4 to almost 7 are chosen. Different methods of analysis (transfer function, frequency domain decomposition, cross-spectrum) will be considered and the variability of the results will be evaluated. Afterward, from the multiple records on gravity dams, a simplified formula is proposed to roughly estimate the acceleration amplification ratio between the crest and the bottom of gravity dams.