Assessment of tsunami hazard due to regional and remote sources: The Coast of the Sea of Okhotsk

The tsunami hazard for the coast of the Sea of Okhotsk requires a careful analysis, because this sea will be a zone of responsibility for the Tsunami Warning Service for the Far East coast of Russia. While it is not subject to such hazards on the part of seismogenic zones that can produce dangerous tsunamis, nevertheless the Sea of Okhotsk is open for penetration of tsunamis that can be produced by sources in other tsunamigenerating zones of the Kuril–Kamchatka region, as well as those of the entire Pacific Ocean. The tsunami hazard for the coast of the Sea of Okhotsk is examined here on the basis of historical observations and the results of numerical simulation for tsunami propagation from hypothetical rupture zones of near and distant earthquakes. It is shown that the real tsunami hazard can only emanate from those regional earthquakes with magnitudes 8.5 or greater that occur in the Kuril–Kamchatka seismogenic zone. Among the remote tsunamigenerating zones in the Pacific, the most dangerous locations are the rupture zones of mega-earthquakes of the class M9 that come from the South America zone and from Papua–New Guinea. These can produce water waves with amplitudes as great as 5 m along the entire coast of the Sea of Okhotsk.