Search

The tsunami-zoning map (possible tsunami heights of a frequency of 1 event within 50 and 100 years) for the coast of the South Kuril Islands have been updated (former map have been developed in 2006). The update is based on the development of the tsunami-activity model, mainly due to the increase of the number of basic coastal locations (from 18 to 62) for which the parameters of the recurrence function were estimated, as well as on the modernization of the numerical model. Serious progress in simulations was achieved in setting the initial conditions, using the seismic tsunami source model. Field surveys on the coast to search for traces of historical and paleotsunami, as well as qualitative documentation of the Tohoku tsunami manifestations allowed to clarify the model of tsunami-activity in Southern Kuril Islands. The sufficiently large amount of data in this case (which is generally untypical for the tsunami) allowed authors, to apply the statistical approach for evaluation of the tsunami hazard distribution along the coast. Estimates of tsunami heights were spread from the basic coastal locations to adjacent parts of the coast using detailed simulation of all significant tsunamis and calculating wave heights at the shoreline. The detailed maps of tsunami-hazard at scale 1:100,000 have been made for the settlements of Yuzhno-Kurilsk, Kurilsk, Malokurilskoe, and Krabozavodskoe.

Storm surges (the significant sea level rises due to a drop in surface atmospheric pressure and an increase in wind velocity during the passage of deep cyclones over the coastal areas) pose a formidable threat to the coastal settlements of Sakhalin and the South Kuril Islands. As a result of flooding of coastal areas, the impact of storm waves on the shores and coastal facilities is sharply increased. The greatest damage caused by surges on 10.11.1990 and 9.11.1995 which affected the most populated southern part of Sakhalin Island. A long-term sea level series were analyzed, recorded at 9 coastal tide gauges located on the coast of Sakhalin Island and South Kuril Islands. Estimates for the maximum heights of the storm surges and tidal level 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 was obtained for the Kurilsk station, where the highest storm surge was recorded. The minimum values were obtained for southwestern coast of Sakhalin Island (Kholmsk and Nevelsk stations) were tides are small. Seasonal and inter-annual variations of strong waves were analysed from the data of visual observations.