150 Meter tall waves?

This article looked really interesting because we have been studying waves but we didn't learn anything about internal waves. A study from the University of Rhode Island has discovered giant underwater waves that occur between layers of cold and warm water. These huge waves have been recorded at up to 150 meters in the South China Sea. The large underwater waves have a large effect on the surface waves. The scientists think that as these waves move towards the southern coast of China they create larger surface waves that increase as they move up the continental shelf. The underwater waves only affect waves created by diurnal tides.

http://www.sciencedaily.com/releases/2010/02/100224165231.htm