Mechanisms of Landslide Tsunami Formation in the Coastal Zone of the Bureya Reservoir and Its Consequences

The mechanisms underlying the breakdown of a landslide body from the slope of the Bureya Reservoir on December 11, 2018, and the formation of an ice tsunami are considered. A model of pulsed disturbance of a water mass, wave dynamics, and processes of its breakdown into a series of waves with a maximum splash height of 90 m are described. On the lower part of the slopes are taiga soils with high ice content, dissipated by ice to the extent that cryogenic processes do not have a cementing effect on soil. The unconsolidated structure and high porosity of the profile were the reasons for their poor resistance to tsunami impacts. The washout of a large mass of organomineral material by the back wave activated the processes of dissolution of chemical compounds of various natures. The uneven distribution of heavy metals along the shores of the reservoir is due to the varying intensity of the processes of crushing of the landslide body and resuspension of fine fractions from its underwater part. The ability of polyvalent cations (Fe+2, +3, Mn+2, Co+2, Ni+2, Cu+2, Zn+2, Cd+2, Pb+2) to form chelate complexes with low-molecular organic substances contributed to their presence in a dissolved state and water pollution at the mouth of the Sredny Sandar River and adjacent areas of the reservoir.