As you follow the news, it is instructive to remember that the United States appreciates the risk of this more than most as we are the country that presided over the worst thermonuclear disaster in the world. In 1954, the United States detonated a thermonuclear device in the Castle Bravo H-bomb test that unexpectedly released 2½ times more explosive force and radiation than our scientists anticipated. The result of this miscalculation was radiation fallout that directly affected inhabited atolls in the Pacific Ocean.
Today, as the North Koreans threaten their own H-bomb test, it is instructive, even if discomfiting, to consider the effects of a nuclear blast on an American city. Click here for an online simulation that allows you to select the target, height of burst and the yield of a nuclear weapon and model the effects of the nuclear blast zones.