Which of the following is not a natural hazard?

Concept

A natural hazard originates primarily from natural processes of the Earth, water, or atmosphere.

A technological or human-made hazard originates from engineered systems, industrial activity, or human operations.

Application

Classify each event by its initiating cause, not merely by the damage it can produce.

Contrast

• An earthquake begins with a sudden release of energy in the Earth's crust, so its origin is geophysical.

• A tsunami begins with rapid displacement of seawater, commonly after an undersea earthquake, landslide, or volcanic event, so its origin is natural.

• A flash flood begins with a rapid rise of water after intense rainfall, a cloudburst, or sudden natural runoff, so its origin is hydrological.

• A nuclear accident begins with failure, malfunction, or error in an engineered nuclear facility or operation, so its origin is technological.

Cross-check

Earthquake, tsunami, and flash flood arise from natural geophysical or hydrological processes. Nuclear accident belongs to the technological or human-made hazard category.

Therefore, the event that is not a natural hazard is nuclear accident.