Earthquakes and Tsunamis

Correct answer: A. Tsunami

Explanation: The governing concept is seafloor displacement. When a powerful earthquake occurs beneath the sea, the ocean floor may suddenly rise, sink, or shift, displacing a large volume of water. Gravity then spreads this disturbance outward as long tsunami waves. Therefore, option A is correct. Drought results from prolonged lack of rainfall, while fog and hailstorm are atmospheric weather phenomena rather than direct results of undersea tectonic movement.

Correct answer: A. Tsunami

Explanation: Ocean trenches commonly occur near convergent plate boundaries, especially where one oceanic plate is forced beneath another. Movement and rupture along such subduction zones can generate powerful undersea earthquakes. If the sea floor is suddenly lifted or lowered, a large volume of seawater is displaced, producing tsunami waves that travel across the ocean and may become destructive near coasts. Thus option A is the relevant hazard. Drought, hailstorms and heat waves are primarily atmospheric or land-surface hazards and are not specifically indicated by the presence of an ocean trench. A trench alone does not guarantee a tsunami, but its tectonic setting makes the association important.