Nuclear weapon effects
Fallout
Radioactive material thrown into the atmosphere by a surface-burst nuclear detonation, which then settles back to earth over hours to weeks.
Surface bursts produce massive fallout because the fireball touches the ground, vaporizing soil and irradiating it with neutron flux. The radioactive debris is lofted into the upper atmosphere and drifts downwind, depositing as a long elliptical plume. Air bursts produce minimal fallout because the fireball does not interact with the ground. The lethal fallout zone of a large surface burst can stretch far downwind: after the Bravo test it was a belt about 270 km long. [1]
Sources
Related terms
Surface Burst
A nuclear detonation at ground level, whose blast reaches less far than an optimum-height air burst but which creates heavy local fallout.
Air Burst
A nuclear detonation above the ground at optimal altitude, maximizing the area affected by blast and thermal radiation while producing minimal fallout.
Half-Life
The time required for half of a quantity of a radioactive isotope to decay.
Acute Radiation Syndrome
The constellation of medical symptoms following a high dose of ionizing radiation, including nausea, immune-system failure, hemorrhage, and death.