The nuclear explosive yields at Hiroshima and Nagasaki

The nuclear explosive yields at Hiroshima and Nagasaki have been calculated from measurements of the damage caused to some objects whose dynamical responses were simple enough to permit analysis. Examples include bent or snapped poles, squashed empty drums and cans, overturned memorial stones, some safe doors and the tops of office cabinets pushed in by the blast. The Hiroshima explosion was 12 ± 1 kilotons and the Nagasaki explosion was 22 ± 2 kilotons.