The correct answer is option 4, "bolt of lightning." A bolt of lightning is considered the minimum short-term natural hazard because it has a relatively short duration and affects a limited area. While a blizzard (option 1), earthquake (option 2), and volcanic eruption (option 3) are all significant natural hazards, they typically last longer and have a larger impact on the environment and human populations.

A blizzard is a severe snowstorm with strong winds and reduced visibility, lasting for an extended period and causing transportation disruptions and infrastructure damage. An earthquake is a sudden shaking or trembling of the ground, which can result in significant destruction of buildings and infrastructure. A volcanic eruption involves the release of magma, ash, and gases from a volcano, potentially causing widespread damage, land deformation, and threats to human health and safety.

Therefore, considering the duration and impact, a bolt of lightning is the minimum short-term natural hazard.