Resonating with the ocean

Tides may be the source of mysterious underwater waves that shape continental slopes

Every day huge, underwater waves surge and ebb far outside the rims of continents. Flowing much faster than the visible tides, these “internal tides” usually don’t make it to the surface or close to the coast. But, because they move around the sediment as it collects below, these waves play big roles in shaping the edges of continental shelves.