How the tide influences dangerous level rises on the coast of the Sea of Okhotsk and adjacent areas in cases of tsunami and storm surges

Abstract

A long-term sea level series were analyzed, recorded at 12 coastal tide gauges located on the coast of the Sea of Okhotsk and the Pacific coast of the Kuril Islands and Kamchatka. Estimates for the maximum heights of the tidal level, storm surges, and tsunamis were obtained separately, as well as for the rare recurrence of the total sea level height with the probability of these individual components superposition. The maximum total height of the sea level without a tsunami were obtained for the Magadan station, where the main factor is anomalously large tides, as well as for Iturup and Matua islands, where the highest storm surges were recorded. The minimum values were obtained for Ust’-Kamchatsk and Malokuril’sk (Shikotan Island) on different flanks of the study area. When a tsunami is included, the maximum values of possible total sea level rises were observed on the Pacific coast of the Kuril Ridge and the influence of tides and meteorologically induced oscillations are small. On the east coast of Kamchatka adjacent to the considered closed area, the role of tsunamis is much smaller. At the Kuril’sk station, where the height of the largest tsunami (Chilean, May 1960) was about a half the strongest surge height, the contribution of the tsunami scarcely affected the resulting estimates. As a rule, the contribution of a tsunami becomes significant at other stations on the coast of the Sea of Okhotsk with a recurrence period of 100 years.