Ten months after the atomic bombing of Hiroshima, Japan, the area was examined for the effect on building materials and structures, and to compare the destruction with that of cities attacked with incendiary bombs. The characteristics of the bomb explosion are explained as there has been some misunderstanding of its effects.
The nature of the terrain permitted a spread of the force of the explosion but many variations in effects were seen. The effect of the heat wave is discounted as no evidence indicates high temperature beyond a small fraction of a second, though radiant heat was effective in unusual ways. The pressure wave produced an effective force that was vertical in the ground zero area and spread to nearly horizontal with distance.
Two significant conditions produced by the pressure wave were observed. Air was compressed and drove solid particles with force that abraded stone and steel. Near ground zero concussion developed compression fractures in stone and heavily reinforced concrete. It is believed the pressure developed was above the crushing strength of an average structural granite.