Today marks the 70th anniversary of one of the darkest days in human history, the Hiroshima nuclear bombing of World War II. Dropped by American Allied forces, claiming the lives of as many as 166,000 citizens within the first four months after detonation, and damaging the health of countless others due to radiation in the years that followed, it was the first time a nuclear attack had been used in combat. Half the deaths occurred on that first day, August 6th, 1945.
Hiroshima was completely levelled. Those that were not immediately killed outside the epicentre of the blast suffered severe burns and radiation sickness, and malnutrition soon kicked in as the humanitarian effort failed to match the scale of the atrocity.
It can be difficult to comprehend the devastation wrought upon Hiroshima, but a number of web tools can help put it into context by showing the effects the 15 kiloton "Little Boy" Hiroshima nuke would have on your city.
The above image is taken from a Pri.org application that uses Google Maps to show the blast radius of the Hiroshima attack, overlaid on over locations around the globe.
Using London's Soho as the blast epicentre in the application, Soho, Covent Garden and Buckingham Palace would be completely obliterated by the Little Boy, with 90 per cent caught in the 0.5 mile radius fireball killed instantly. The one mile blast radius, stretching Mayfair over the Thames into Lambeth, would be engulfed in a spreading firewall and obliterated by the blast – 70 per cent of people in this zone would be killed instantly. A raging fire would then spread three miles across London, stretching west from Kensington to Whitechapel in the east, north from Chalk Farm to Camberwell in the south. And even as far as 12 miles away from the epicentre in places like Dagenham, windows on buildings would be found broken.
Though the estimation doesn't take into account weather and differences in topography and architecture, it gives you a good indication of the horror that occurred. You can try the simulator below:
In terms of numbers of fatalities and the effects of fallout, Alex Wellerstien's Nukemap application makes for similarly grim reading. With the London Eye as the blast's epicentre, as many as 353,667 could be within the 1 psi range of the detonation.
The most frightening thing? The nuclear weapon used in the Hiroshima attack is basically a pea shooter by today's standards. Even by the 1960s, the Soviet Union had developed and tested the Tsar Bomba, the most powerful nuclear weapon ever detonated in testing, which had a 50,000 kiloton (50 megaton) payload. That leaves you with a blast radius of 22 miles, enough to wipe out an area with a radius stretching from Wembley to Havering. The fatalities would number in the millions.