Which natural hazard is most directly linked to seafloor displacement and can generate waves after an undersea earthquake?

• A. Earthquakes
• B. Volcanoes
• C. Tsunamis
• D. Floods

Answer: (C)

When the seafloor moves abruptly during an undersea earthquake, it displaces a huge amount of seawater and starts waves that travel across the ocean. Those waves are called tsunamis. The key idea is that the hazard described is the waves themselves caused by the sudden vertical shift of the sea floor, not the ground shaking on land or the trigger itself. Tsunamis form because the displaced water column sets off a wave train that can propagate fast in deep water and grow taller as it approaches shallower coastal waters, leading to powerful flooding when they reach shore. While earthquakes can be the trigger, and volcanic activity can also generate tsunamis in some cases, floods are not tied to this process.