Are Solitary Internal Waves Solitons?

Results of fully nonlinear numerical simulations of the interaction of two mode-1 solitary internal waves, both propagating in the same direction, are presented. After the interaction, two solitary internal waves emerge. The large wave is slightly larger than the initial large solitary wave, while the small one is slightly smaller than the initial small solitary wave. Some small-amplitude trailing mode-1 and mode-3 waves are generated by the interaction.