Ivy Mike on Sydney
10.4 Mt thermonuclear weapon · Australia · Population 5,312,000 · Density 2,100/km²
About this scenario
This page calculates what would happen if the Ivy Mike (USA, 1952) detonated over Sydney (Australia). First hydrogen bomb test.
The largest city in Australia and host of the 2000 Summer Olympics. With an urban-core density of about 2,100 people per km², even a relatively small detonation over the city center would affect a large population.
The Ivy Mike delivers 10.4 Mt of explosive yield — 693× 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 (Ivy Mike over Sydney)
| Effect zone | Radius | Est. affected |
|---|---|---|
| Fireball (vaporization, 100% fatal) | 5.86 km | ~226,846 |
| Severe blast (20 PSI, ~98% fatal) | 10.20 km | ~446,024 |
| Moderate blast (5 PSI, ~50% fatal) | 21.80 km | ~1,224,373 |
| Light blast (1 PSI, glass injuries) | 62.01 km | ~1,111,809 |
| 3rd-degree thermal burns | 29.72 km | — |
| 2nd-degree thermal burns | 53.23 km | — |
Estimated total fatalities: ~1,897,243 · Estimated total affected (inside 1 PSI light-blast radius): ~25,371,516.
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 Ivy Mike struck ground level rather than detonating optimally above Sydney.
| Effect zone | Radius (surface burst) |
|---|---|
| Fireball | 4.69 km |
| Severe blast (20 PSI) | 5.61 km |
| Moderate blast (5 PSI) | 11.99 km |
| Light blast (1 PSI) | 34.11 km |
| 3rd-degree thermal burns | 17.83 km |
| Lethal fallout zone | ~485.3 km |
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See the actual blast zones overlaid on a map of Sydney 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 Ivy Mike detonated over Sydney?
In an air burst over Sydney, the Ivy Mike (10.4 Mt) would produce a fireball about 5.86 km in radius. The 5 PSI moderate-blast zone — where most residential buildings collapse — would extend to 21.80 km. Light blast damage and shattered windows would reach 62.01 km. Given Sydney's urban density (~2,100/km²), this scenario yields an estimated 1,897,243 immediate fatalities and about 1,111,809 additional injured.
How many people would die in Sydney from a Ivy Mike strike?
An air burst of the Ivy Mike over Sydney could cause an estimated 1,897,243 immediate fatalities and 1,111,809 additional injuries. The fireball alone (radius 5.86 km) would kill approximately 226,846 people; the severe-blast zone (20 PSI, radius 10.20 km) would add 446,024; the moderate-blast zone (5 PSI, radius 21.80 km) would add 1,224,373 more. Real numbers depend heavily on time of day, sheltering, weather, and altitude of detonation.
What is the blast radius of the Ivy Mike on Sydney?
For an air burst over Sydney: fireball 5.86 km, severe blast (20 PSI) 10.20 km, moderate blast (5 PSI) 21.80 km, light blast (1 PSI) 62.01 km. Thermal radiation causes 3rd-degree burns out to 29.72 km. A surface burst would shrink the blast radii by roughly 40 percent but generate massive radioactive fallout extending ~485 km from ground zero.
Is the Ivy Mike bigger than the bomb that hit Hiroshima?
The Hiroshima bomb (Little Boy) had a yield of about 15 kilotons. The Ivy Mike at 10.4 Mt is 693× more powerful than the Hiroshima bomb.