What causes tsunamis to travel long distances?

Tsunamis travel long distances because they involve the movement of vast amounts of water, not just surface waves. When an underwater disturbance, like an earthquake, displaces a large volume of water, it creates waves that propagate outward across the ocean at high speeds. Unlike regular waves, which are driven by wind and lose energy quickly, tsunamis retain their energy due to their long wavelengths. This allows them to travel thousands of kilometres across the ocean with little loss of energy.