Nuclear weapons: estimated blast radius from a one megaton bomb by force

The force of a one megaton nuclear explosion at ground level would be roughly 100 pounds per square inch (psi) within one mile of the explosion. Such an explosion would leave a crater in the earth measuring at least 175 feet (50 meters) deep and 700 feet (200 meters) wide, and would throw a vast quantity of radioactive dirt and debris into the atmosphere, which would cause further destruction and toxicity as it fell back to earth. In contrast to a ground level explosion, an explosion at 8,000 feet (1.5 miles / 2.5km) above the earth's surface would create a smaller quantity of fallout and debris, but would have a much wider blast radius.