Why can people out of at sea not feel a tsunai below them but people on the land can?

People out at sea typically do not feel a tsunami because the waves are long and low, often passing beneath boats without significant vertical displacement. In deep water, the wave height can be just a meter or less, making it difficult to notice. However, as the tsunami approaches shallower waters near the coast, it slows down and the wave height increases dramatically, causing the ground to shake and creating a noticeable impact for those on land. Thus, the experience of a tsunami is vastly different for those at sea versus those onshore.