Elizaveta Tsukanova: Tsunami Wave Transformation in the Sea of Japan under the Influence of Bottom Relief

Elizaveta Tsukanova’s talk focused on tsunami-wave transformation in the Sea of Japan and on the role of bottom relief in their propagation. She began with a general overview of tsunami physics: most tsunami waves are associated with earthquakes in subduction zones, where vertical seafloor displacement changes the ocean surface, but landslides, atmospheric processes, and volcanic activity can also act as sources.

The central part of the seminar addressed how long gravity waves respond to water depth and seafloor shape. Participants discussed why a tsunami slows down and grows in amplitude as it enters shallower water, how narrow straits and natural frequencies of basins can amplify the signal, and why submarine highs may not only change wave amplitude but also trap part of the wave energy.

A separate block concerned the choice of bathymetric data for modelling. Elizaveta described comparisons between different datasets for the Sea of Japan, checks of coastline geometry against satellite data, and comparisons of depths with navigation charts for specific coastal areas. The discussion showed that differences in input bathymetry can substantially affect tsunami-propagation calculations and the interpretation of model results.

During the questions, participants discussed numerical-model verification in detail. The conversation covered reconstruction of historical tsunami sources, comparison with tide-gauge records and DART deep-ocean stations, and the reasons why local coastal effects make direct comparison with observations difficult. The seminar also touched on operational calculations: for coarse warning estimates, modern computing resources can run simulations quickly, especially when source scenarios are prepared in advance.

The final discussion focused on tsunami-warning systems in Russia and abroad. Participants talked about magnitude-and-location criteria, the role of observing stations, differences between open-ocean sensors and coastal tide gauges, and the shortage of instruments in the Sea of Japan. The discussion also covered possible tsunamis in the Arctic, including landslide sources and the observational challenges of regions with sparse instrumental networks.