@25 days until Hiroshima Summit: Atomic Bomb’s blast

by Fumiyasu Miyano, Staff Writer

A single atomic bomb was dropped by the U.S. One half of the energy generated by its detonation is said to have been a “blast.” The estimated value of the blast speed at the hypocenter was about 440 meters per second. The blast blew over many of the buildings within a 1.8-kilometer radius from the hypocenter.

The blast’s enormous power can be imagined in traces of the remained buildings, too. The window frames at the main building of Hiroshima Red Cross Hospital, located 1.5 kilometers from the hypocenter, were greatly deformed by the blast. The frames are now placed as a monument near the current Hiroshima Red Cross Hospital & Atomic-bomb Survivors Hospital in Naka Ward, Hiroshima. At Honjido hall of the Hiroshima Toshogu Shrine in Higashi Ward, located 2.1 kilometers away from the hypocenter, an unusual crack was found in the upper part of its pillar when repair work for the hall was ongoing in December, 2021. An expert who checked the crack estimated it was breakage caused by the bomb blast. A member of the Toshogu Shrine staff said, “We want to pass it down to later generations so the real condition of the bombing can be conveyed.”

(Originally published on April 24, 2023)