33. A surface burst Tesu_l-ts in the creation of t-arge and healXr radioactive particles which wifr far-1 dovn ,rithin ;i;;;;"'i"orrna ground zero, other, lighter and smarrer particres. however, wifl fo110w the fireb;11 and c10ud r.,rirr." .,rp,drift with the winds and then iqU.Ao*rr-ln u. piurne_fif." area in the generaf direction of persistine winds. I,lrrir-e these pirti"r"" are sma"ller than those closer to- ground zero, thev wiff on " ";;;; """i""5-"i*r be visible as dust vhenever fa110ut is sufficient to. represent a significant innaediate hazard. This falrout wilr (/i11 start coming dor,m withln fess irr.i'.,'-i"i"' and keep fauing for about a day or tvo delending on the distance froo. g"".-a "."o. The smallest particles, finally, r'ri1' be ejected into the stratospheie - .t-i"."t for a weaFon of large yiefd - and remain there for months or years, before leturning to the ground again. An airl5:.^:l-:n: :th:: 13"d, i.e. a burst *r.."" irr"-rirebat_t if *"ii .i""."tr.e sround, rr-r cause essentiarly arl r_es idu€J- radiation particles to ascend vith the firebarl and mushroom cloud' Eventually they vi.l "p."ia o,rt and return to the ground as dilute',rorld-wide faflout. 3l+. There are a. nurberthe most important ;r;":L'ff:";:."':::i#i":i'"ff:iil.::i '11"fi::I il i:'".;:k" wind' or if the winds are blowing i" aiir!""il iirections "t -ai ii""""i"alt itude s , the fallout area wilf have a very complicated shape vith possible ,,hot snots,,.Al 35 /392 Englistt Annex Page 1?0 Fig. A:5 Fallout Patterns The upper part of the figure shows an idealized set of dose-rate contours' Numbers are dose-rates ,'r, iaaTtt at one hour after the explosion' and the size of the contours corresfonds to a 10 Mt,- 56-percent fission surface burs! and a 50 kro/h .ff""iliri wind speed. The lower part is a hy-pothetical Dicture of ho\^r the ".t t.ilot'l patt;rn might look in reality' Note the change in the overall direction of the pattern' (Froi: Effects of Nuclear Weapons' Washington 1977')^/ 35 /392 English :lnn ex iaae .L / _L