Kim, M.S.; Kim, H.S.; Kim, Y.K.; Gu, B.H.; Lee, H.J., and Woo, S.B., 2016. Double resonance effect at Daeheuksando Port caused by air pressure disturbances in Yellow Sea on 31 March 2007. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1142 - 1146. Coconut Creek (Florida), ISSN 0749-0208.We found that an internal resonance, combined with other topographic effects, following an external resonance could significantly amplify insignificant sea-level oscillations in the open sea to wave heights of several meters in a coastal area. Sudden sea-level oscillations characterized by high frequencies (0.0042–0.5 min−1) and a maximum wave height of about 1 m were observed at Daeheaksando Port (DP) on 31 March 2007. These sea-level oscillations, which caused heavy casualties and large economic loss, were also detected along the west coast of South Korea. Particularly, at DP, there were sea-level oscillations that had significant power spectrum in a specific period band. When the maximum power spectrum of the sea-level oscillations increased rapidly, the period of the maximum power spectrum converged toward the fundamental period of the port. However magnitude of the air pressure disturbance at DP could not make such sea-level oscillations. The resulting sea-level oscillations were likely amplified by the free waves generated by air pressure disturbances at KyukRyulbeedo (KR) and propagated to DP. The initial magnitude of the disturbances propagated from Shandong was approximately 2.5 hPa/10-min, based on results of the atmospheric model. Theoretically, a 2.5 hPa air pressure change can make sea-level oscillations of about 2.5 cm, but it made meteotsunamis in the port because of the double resonance effect on 31 March 2007.