Tsar Bomba on São Paulo
50 Mt thermonuclear weapon · Brazil · Population 12,330,000 · Density 7,400/km²
About this scenario
This page calculates what would happen if the Tsar Bomba (USSR, 1961) detonated over São Paulo (Brazil). Largest nuclear weapon ever tested.
The largest city in the southern hemisphere and Brazil's economic capital, with over 22 million in the metro area. With an urban-core density of about 7,400 people per km², even a relatively small detonation over the city center would affect a large population.
The Tsar Bomba delivers 50 Mt of explosive yield — 3,333× more powerful than the Hiroshima bomb. The tables below show calculated effect radii for an air burst (optimized for blast spread) and a surface burst (which produces massive fallout).
Air-burst effects (Tsar Bomba over São Paulo)
| Effect zone | Radius | Est. affected |
|---|---|---|
| Fireball (vaporization, 100% fatal) | 10.99 km | ~2,807,331 |
| Severe blast (20 PSI, ~98% fatal) | 17.13 km | ~3,876,446 |
| Moderate blast (5 PSI, ~50% fatal) | 36.60 km | ~12,161,976 |
| Light blast (1 PSI, glass injuries) | 104.12 km | ~11,043,852 |
| 3rd-degree thermal burns | 56.58 km | — |
| 2nd-degree thermal burns | 101.33 km | — |
Estimated total fatalities: ~18,845,753 · Estimated total affected (inside 1 PSI light-blast radius): ~252,021,177.
Surface-burst effects (with fallout)
A surface burst trades blast spread for radioactive fallout — much smaller blast radii but a large lethal fallout plume drifting downwind. This is what would happen if the Tsar Bomba struck ground level rather than detonating optimally above São Paulo.
| Effect zone | Radius (surface burst) |
|---|---|
| Fireball | 8.79 km |
| Severe blast (20 PSI) | 9.42 km |
| Moderate blast (5 PSI) | 20.13 km |
| Light blast (1 PSI) | 57.27 km |
| 3rd-degree thermal burns | 33.95 km |
| Lethal fallout zone | ~909.4 km |
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See the actual blast zones overlaid on a map of São Paulo with population-density-based casualty estimates updated in real time as you move the detonation point.
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FAQ
What would happen if the Tsar Bomba detonated over São Paulo?
In an air burst over São Paulo, the Tsar Bomba (50 Mt) would produce a fireball about 10.99 km in radius. The 5 PSI moderate-blast zone — where most residential buildings collapse — would extend to 36.60 km. Light blast damage and shattered windows would reach 104.12 km. Given São Paulo's urban density (~7,400/km²), this scenario yields an estimated 18,845,753 immediate fatalities and about 11,043,852 additional injured.
How many people would die in São Paulo from a Tsar Bomba strike?
An air burst of the Tsar Bomba over São Paulo could cause an estimated 18,845,753 immediate fatalities and 11,043,852 additional injuries. The fireball alone (radius 10.99 km) would kill approximately 2,807,331 people; the severe-blast zone (20 PSI, radius 17.13 km) would add 3,876,446; the moderate-blast zone (5 PSI, radius 36.60 km) would add 12,161,976 more. Real numbers depend heavily on time of day, sheltering, weather, and altitude of detonation.
What is the blast radius of the Tsar Bomba on São Paulo?
For an air burst over São Paulo: fireball 10.99 km, severe blast (20 PSI) 17.13 km, moderate blast (5 PSI) 36.60 km, light blast (1 PSI) 104.12 km. Thermal radiation causes 3rd-degree burns out to 56.58 km. A surface burst would shrink the blast radii by roughly 40 percent but generate massive radioactive fallout extending ~909 km from ground zero.
Is the Tsar Bomba bigger than the bomb that hit Hiroshima?
The Hiroshima bomb (Little Boy) had a yield of about 15 kilotons. The Tsar Bomba at 50 Mt is 3,333× more powerful than the Hiroshima bomb.