Key Facts
• August 6, 1945: Atomic bomb dropped on Hiroshima at 8:15 AM.
• 7:09 AM: Air raid warning issued; 7:31 AM: Warning lifted.
• Survivors recall pre-bomb sounds: marching soldiers, sirens, children playing.
• Explosion sound not recorded; survivors report no memory of the blast sound.
• Tohoku University simulated the blast: shockwave pressure reached 35 kPa.
• 35 kPa pressure could destroy wooden homes; eardrum rupture occurs at ~30 kPa.
• Shockwave traveled faster than sound, causing widespread hearing damage.
• Within 2 km of ground zero, eardrum ruptures likely; temporary hearing loss extended to 7 km.
• 1953 U.S. nuclear test (Annie Experiment) recorded similar explosion sounds.
• Survivor Shingo Naito (6 at the time) recalls “indescribable destruction sounds.”
• Naito’s siblings died under rubble; he survived by being near a bomb shelter.
• Today, Naito cherishes peaceful sounds like cicadas, symbolizing normalcy.
Summary
Eighty years after the atomic bombing of Hiroshima, survivors and researchers reflect on the sounds of that day. Pre-bomb sounds included sirens, marching soldiers, and children playing. However, many survivors do not recall the explosion sound due to shockwaves traveling faster than sound, causing hearing damage. Tohoku University simulations revealed that shockwave pressure reached 35 kPa, enough to destroy wooden homes and rupture eardrums. Within 2 km of ground zero, eardrum ruptures were likely, and temporary hearing loss extended up to 7 km. Historical comparisons to the 1953 U.S. Annie Experiment provide insights into the bomb’s sound. Survivor Shingo Naito, who was six at the time, recalls the destruction and the loss of his siblings. Today, he finds solace in peaceful sounds like cicadas, symbolizing a return to normalcy. This research and survivor accounts highlight the devastating impact of the Hiroshima bombing and the importance of preserving peace.
