1f5, For an explosion at ground surface with this yield, there happens to be anexperirnental observation regarding the extent of the fallout area. According toofficial United. States sources, Ij/ the 15 l4t. test explosion code-naned CASTLE BRAVO and carried out at Bikini Ato11 on 1 ltarch 1!!\ "caused su,bstantiaf conbaroination over an arep ..f m^rF f l-'n ? noo <nLlsre niIes". (This orca, TOuGn,y 18,ooo k 2, "o"ra-noi ;;;;.;;.;;;';;;iv'i."ir.i". rndicatcd above, houevur, rs "substantial contamination" is believed to be, in tn:-s Lropical a,nd peacer-irnecontext, anything that uoul-d cause a non-zero risk of acute radiation injury dur.ing veeks of ex1osure in open air.) 17?. To sunr up the effects of a nuclear veapon explosion on a. cily and fce r-s lng oncities in the 0,1-1 nil-lion inhabitants range (to vhich indeed most cities in thewcrld belong), the diagram in figure fX vas constructed-. ft has been drawr assuming a surprise attack vith one weapon e exploded at a height chosen to optimizethe area of blast d.estruction to ordinary residential houses and lribh ground.-zeroin the geornetrical centre of the city, and further assrnin.g t\aL Lne ropr-latjor. -LsevenJy distributed over the cityrs area. The diagrar slrcws. for thr.ce po!.ulrlior densities, the weapon yields vhich cause roughly )O per cent fafalitlties ir roediun-sized cities. !2/ GLasstone and Dofan, op. cib.t\/ 35 /392 Xnglish Annex o_o -jo_c E o 5XI rr.l9o o F d o (JOoo<\.1E o o(\l ooO o E r+r -o E q)dN tr -.r E U}o{, J 3.d E oaz A. 3 !)(azta-n OHo Ei ETH (/)|fEHHm< F]t4>>o F{AOE E4 Z o= tsl pct H -aoA/35/392 English Annex fage ot B. Effects of a liraited nucl-ear attaek L6/ 178, The tenn ttl-imited nuclear attack" can be interpreted only in a specific context. In general, however, the term irnplies a certain d.egree of restraint in the