Wie tief kommen Kernwaffensprengköpfe unter die Erde ?

[Cluster]

http://en.wikipedia.org/wiki/Nuclear_bunker_buster

(...) While penetrations of 20–100 feet were sufficient for some shallow targets, both the Soviet Union and the United States were creating bunkers buried under huge volumes of soil or reinforced concrete in order to withstand the multi-megaton thermonuclear weapons developed in the 1950s and 1960s. Bunker penetration weapons were initially designed out of this Cold War context. (...)