1 Megaton Surface Blast: Fallout One of the effects of nuclear weapons detonated on or near the earth’s surface is the resulting radioactive fallout. Immediately after the detonation, a great deal of earth and debris, made radioactive by the blast, is carried high into the atmosphere, forming a mushroom cloud. The material drifts downwind and gradually falls back to earth, contaminating thousands of square miles. This page describes the fallout pattern over a seven-day period.
Assumptions Wind speed: 15 mph Wind direction: due east Time frame: 7 days
3,000 Rem* Distance: 30 miles Much more than a lethal dose of radiation. Death can occur within hours of exposure. About 10 years will need to pass before levels of radioactivity in this area drop low enough to be considered safe, by U.S. peacetime standards.
900 Rem Distance: 90 miles A lethal dose of radiation. Death occurs from two to fourteen days.
300 Rem Distance: 160 miles Causes extensive internal damage, including harm to nerve cells and the cells that line the digestive tract, and results in a loss of white blood cells. Temporary hair loss is another result.
90 Rem Distance: 250 miles Causes a temporary decrease in white blood cells, although there are no immediate harmful effects. Two to three years will need to pass before radioactivity levels in this area drop low enough to be considered safe, by U.S. peacetime standards.
*Rem: Stands for “roentgen equivalent man.” This is a measurement used to quantify the amount of radiation that will produce certain biological effects.
The good news is we'll never drop a 1 megaton nuclear bomb anywhere, least of all Pyongyang. Small tactical nuclear bombs/missiles could be used to stop their infantry advance, destroy their artillery and maybe cutr their supply lines. It would save hundreds of thousands of lives in the event of a full-scale invasion by the Noks, and fall out would be minimal.