According to South Korean news agencies and the US Geological Survey, North Korea has just performed a weapons test with a nuclear bomb. It's only a small one, measuring about 10kt, but that would still have an effect on a city if it were detonated there. Just what would happen to the world's cities if you dropped a 10kt nuke in the middle?
Using Nukemap, we're able to find out. Nukemap is a nifty little tool that lets you plug in a city, town or even the middle of nowhere, pick a bomb and find out what sort of damage it would do. To give you some perspective on North Korea's test device of 10 kilotons, the bomb that vaporised Hiroshima measured in at 16 kilotons, while the largest nuclear bomb ever tested measures 100 megatons. That one was designed in the ex-USSR with a blast radius of a few hundred kilometres.
A nuclear blast has several different zones, and here's how Nukemap illustrates them in the below examples:
• Yellow: Fireball radius — 0.08 km / 0.05 mi (0.02 km² / 0.01 mi²) Maximum size of the nuclear fireball; relevance to lived effects depends on height of detonation. • Red: Air blast radius — 0.6 km / 0.37 mi (1.13 km² / 0.43 mi²) 20 psi overpressure; heavily built concrete buildings are severely damaged or demolished; fatalities approach 100%. • Green: Radiation radius — 1.3 km / 0.81 mi (5.32 km² / 2.05 mi²) 500 rem radiation dose; between 50% and 90% mortality from acute effects alone; dying takes between several hours and several weeks. • Blue: Air blast radius — 1.58 km / 0.98 mi (7.84 km² / 3.03 mi²) 4.6 psi overpressure; most buildings collapse; injuries universal, fatalities widespread. • Orange: Thermal radiation radius — 1.77 km / 1.1 mi (9.79 km² / 3.78 mi²) Third-degree burns to all exposed skin; starts fires in flammable materials, contributes to firestorm if large enough.
Without further ado, the world at war: