The map above simulates a 300-kiloton nuclear airburst over Seoul, South Korea — roughly the size of a modern deployed warhead. The coloured rings show the estimated fireball, the zones of heavy, moderate and light blast damage, the reach of the thermal flash and the ionizing-radiation dose. Drag the marker or change the weapon in the full simulator to explore other scenarios.
The metropolitan area is home to about 25 million people — the rings above are drawn to real scale over their homes.
The marker is on Seoul City Hall, between Gwanghwamun and Namdaemun. The 1.9 km zone of total destruction covers Gyeongbokgung and Deoksugung palaces, the government complex, Myeongdong and Seoul Station; the 4.7 km collapse ring reaches Namsan, Dongdaemun, Itaewon and the Blue House's former grounds. Third-degree burns extend to about 7.5 km — Hongdae, Yongsan, Seongsu and across the Han River to Yeouido — and the 14.5 km ring of broken windows covers Gangnam, Jamsil's edge, Mapo, Sinchon and the whole of old Seoul inside the mountains.
About 25 million people live in the Seoul Capital Area, and Seoul itself is the scenario where terrain matters most among the large cities here: Bukhansan, Inwangsan and Namsan would shade the neighbourhoods behind them from the thermal flash — switch on terrain shadows to see it. Seoul is 40 km from the Demilitarized Zone and North Korea's largest test, in 2017, was estimated at well over 100 kilotons. See Nuclear arsenals.
Language 
