Within a concrete bunker less than 10 kilometers from the epicenter, Tian Zhan also saw the explosion through the observation window.
However, compared to the people at sea, what the IAEA observers saw was an inferno on earth.
Their bunker was situated near the local forest park and its construction began from the very start of establishing the controlled area, built solidly with concrete, rebar, and lead plates. Theoretically, it could directly withstand a nuclear blast 5 kilometers above, and it was extremely sturdy.
Personnel entered and exited through an underground passage temporarily constructed from a farther location, and there was no doubt about its robustness.
The first thing they saw was a blazing fireball flashing across the narrow view of the observation window, and then the blindingly pale light turned the observation window into a super-bright screen emitting a cold glow.