The Atomic Bombings of Hiroshima and Nagasaki

This report describes the effects of the atomic bombs which were dropped on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. It summarizes all the authentic information that is available on damage to structures, injuries to personnel, morale effect, etc., which can be released at this time without prejudicing the security of the United States.

This report has been compiled by the Manhattan Engineer District of the United States Army under the direction of Major General Leslie R. Groves.

Foreword

Introduction

The Manhattan Project Investigating Group

Propaganda

Summary of Damages and Injuries

Main Conclusions

The Selection of the Target

Description of the Cities Before the Bombings

Hiroshima

Nagasaki

The Attacks

Hiroshima

Nagasaki

General Comparison of Hiroshima and Nagasaki

General Description of Damage Caused by the Atomic Explosions

Total Casualties

The Nature of an Atomic Explosion

Characteristics of the Damage Caused by the Atomic Bombs

Calculations of the Peak Pressure of the Blast Wave

Long Range Blast Damage

Ground Shock

Shielding, or Screening, from the Blast

Flash Burn

Characteristics of Injuries to Persons

Burns

Mechanical Injuries

Blast Injuries

Radiation Injuries

Shielding from Radiation

Effects of the Atomic Bombings on the

Inhabitants of the Cities

Appendix: Father Siemes' eyewitness account