 |
| Gamera 3: Revenge of Iris |
Gamera’s Plasma Fireball is one of the kaiju’s most iconic and frequently used attacks — a blazing projectile powerful enough to defeat many of his greatest enemies. But just how destructive is this technique in physical terms?
In this post, we’ll analyze the explosions shown in the film using scaling, thermodynamics, and blast physics to estimate the true energy behind Gamera’s signature attack.
Fireball Size and Energy Estimation
In the scene, Gamera’s attack is shown engulfing a massive area.
At the moment of the attack, Gamera is located near the Tokyu Department Store, and the explosion can be seen extending toward the Hachikō statue. According to Google Maps, the straight-line distance between these two locations is roughly 70 meters. Visually, the explosion appears to travel even farther, but due to the lack of precise reference points, we will conservatively use 70 meters as our working radius.
To estimate the fireball’s yield, we can apply a heat transfer approach, calculating the energy required to heat the entire volume of air within the fireball to its estimated temperature.
Parameters
- Radius = 70 meters
- Diameter = 140 meters
- Area = 15,393 m²
- Volume = 1,436,755 m³ of air
- Air mass = 1,760,024 kg of heated air
- Fireball temperature = 3000°C (This is not an official value but an estimate based on the destruction of Gyaos, who previously survived atmospheric reentry.)
Temperature change:
- Specific heat capacity of air = 1005 J/(kg·K)
Energy Calculation
This corresponds to roughly 1.3 kilotons of TNT.
While this may appear modest compared to nuclear-scale explosions, it fits well with the level of destruction shown in Shibuya, which covers about 15.14 km². According to Nukemap, devastating an area of that size would require roughly 9 kilotons of energy.
Considering that multiple blasts are fired during the scene, it is entirely plausible that each individual fireball operates within the kiloton range.
Explosion Scaling Using Iris as Reference
For this second estimate, we will use a scale comparison based on Iris’s official height, which is listed as 99 meters, in order to determine the size of the explosions.
 |
| Height: 99 meters (at full growth) Weight: 199 tons (at full growth) Wingspan (extended): 199.9 meters (at full growth) Maximum tentacle reach: 1999 meters Maximum flight speed: Mach 9 Place of origin: Unknown (somewhere in outer space) obtained from the Gamera.jp website |
Only one explosion will be analyzed — the one located to the left side of the scene — since it is the closest explosion to Iris and therefore provides the most reliable scaling reference.
 |
| Gamera 3: Revenge of Iris |
- Iris height = 99 meters = 185 px
- Explosion diameter = 360 px = 182 meters
- Explosion height = 235 meters
- Explosion radius = 96 meters
- Explosion duration = 0.1 seconds
- Explosion area = 28,952 m²
- Explosion volume = 6,803,935 m³
Sedov–Taylor Blast Energy Estimate
To estimate the explosion yield, we apply the Sedov–Taylor blast wave solution, a method used in many previous analyses.
This corresponds to roughly 231 tons of TNT.
This result is lower than the 1.1 kiloton estimate produced by Nukemap, but that difference is largely due to the assumed expansion velocity of the blast. Nukemap models explosions with dynamics similar to nuclear detonations, whereas the observed cinematic expansion speed here appears somewhat slower.
Alternative Heat-Based Estimate
If we instead apply the same thermal energy method used in the previous section, the energy required to generate each fireball rises to approximately:
This places the attack comfortably within the kiloton-scale range, consistent with the level of destruction shown in the scene
Conclusion
By combining scene scaling, thermodynamic calculations, and blast-wave physics, we can estimate the destructive output of Gamera’s Plasma Fireball. Depending on the method used, the results range from hundreds of tons to several kilotons of TNT per blast.
While the exact value varies with the assumptions applied, both approaches consistently place the attack within the high-explosive to kiloton-class range, which aligns well with the large-scale destruction shown in the film and explains why the Plasma Fireball remains one of Gamera’s most effective combat techniques.
Read More.
0 Comments