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
**Analysis**
The text appears to be discussing the effects of a nuclear weapon explosion on a city and its population. The language used is technical and scientific, with references to specific data and sources. The text also mentions the concept of "substantial contamination" and the risk of acute radiation injury. This suggests that the text is focused on the scientific and health aspects of a nuclear attack, rather than economic or social impacts.

**Category**
Health, Science and Technology