This page shows a simulation of the Topol (SS-25) (currently in Russian arsenal) (800 kt) nuclear bomb (800 kt) detonated over London, England. The map displays the estimated fireball, the zones of heavy, moderate and light blast damage, thermal radiation and ionizing radiation. Click «What does that mean?» for a detailed legend, or run your own detonation on the main page.
The 800-kiloton warhead of the Topol (SS-25) is the kind of weapon a strategic missile actually carries today — about 50 Hiroshimas, delivered in roughly 30 minutes. On this map it is an airburst, the height chosen to maximise the area of heavy blast damage. The fireball is about 1.8 km across; total destruction (20 psi) reaches roughly 2.6 km, residential collapse (5 psi) about 6.5 km, third-degree burns on exposed skin about 11.5 km, and broken windows with flying-glass injuries (1 psi) about 20 km.
What that means in London
Centred on Westminster, the 2.6 km zone of total destruction covers Parliament, Whitehall, Buckingham Palace, Trafalgar Square and Waterloo. The 6.5 km collapse ring takes in the City of London, the South Bank, Hyde Park, King's Cross, Elephant and Castle and Chelsea; burns to 11.5 km reach Canary Wharf, Hampstead, Brixton, Shepherd's Bush and Greenwich. The 20 km ring of broken windows extends to Wembley, Stratford, Croydon's northern edge, Richmond and Walthamstow — most of Inner London and a good part of the outer boroughs.
About 9 million people live in Greater London and most of them inside the outer ring. The city is almost flat along the Thames, so terrain shadows are negligible; the river itself is too narrow to absorb much blast. During the Cold War British planners assumed London would receive several warheads of this size rather than one. The 100-megaton scenario shows what the entire South East would look like.
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