Stories from Physics for 11-14 14-16
Waves are not restricted to the surface of fluids but can occur, under the right conditions, within them as well. Internal waves can occur at the boundary between layers of fluid with different densities. The amplitude of internal waves can be an order of magnitude greater than that of surface waves. This is because the generation of internal waves requires less energy than for surface waves as the difference in densities between layers is typically less than for the water-air boundary. Some of the largest ocean waves are internal waves — in the Luzon Strait, in the South China Sea, subsurface internal waves with a height of 170 m have been recorded.