Internal waves generated by explosive eruptions of underwater volcanoes and their effect on the sea surface

An analysis of internal waves arising in a two-layer fluid during an explosive eruption of an underwater volcano is performed. Processes occurring in the near zone are parameterized by the initial source in the form of a displacement of the water column, as proposed by Le Méhaute (Mehaute, Adv Hydrosci 7:1–79, 1971). Then the linear problem is solved, and the features of internal waves are determined depending on the ratio of layer thicknesses, source radius, and distance to the source. The calculated wave field has the form of frequency-modulated groups, where the leading group has the maximum amplitude. The wave of maximum height in this train arrives much later than the weak leading wave, which makes it possible to prepare for the approach of dangerous waves. Estimates of the horizontal speed of currents on the sea surface caused by internal waves have been carried out. It was shown that internal waves can cause noticeable variations in wind ripples detected by remote sensing.