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different heights, it is impossible to apply a@ single fallout
pattern to all detonations,
The area of signif icdnt contamination
will be largely dependen: upon the yield of the bé@mb.
Its
location, with regard to ground zero, and its widih and length,
will be determined by the resultant direction andivelocity of the
winds at various heights and distances.
In generg@l terms it will
be an elongated cigar-shaped area extending "downwind" from the
point of burst.
It i8 obvious that dimensions depend upon
Bo many
uncertainties as to preclude precise predictions.|
Realistic
assumptions, however, based on experimental data
From the Pacific
Proving Grounds provide an adequate basis for civil defense planning for operational preparedness.
The thermonuclear bomb fired at the Bikin¥
Atoll on March
1, 1954, resulted in an area of contamination (1@0
roentgens or
more cumulative dose 24-48 hours after the detonation) of nearly
14,000 square miles with the heaviest concentratJon falling on
the central portion of the ellipse extending som@
the point of burst.
distance from
Some of the early fallout fgom this explosion
occurred in the form of a fine dust which lookedJlike snow.
On
the inhabited islandgabout 170 miles down-wind,Jthe fallout began
about eight hours after the detonation and contigued for several
hours,
On the basis of gamma dose radiation effeBt, the March 1,
1954 explosion heavily contaminated (500 roentgehhs or more
cumulative dose 24-48 hours after the detonation)
extending approximately 160 miles down-wind and
width.
an area
bp to 40 miles in
On the same basis and with the assumptidh of no shelter or
other protective measures, it has been estimated that in a down-
Wind belt about 140 miles long and up to 20 milds
wide the
residual radiation would have been fatal to neawly all persons
8
Ubeadr SFISD
DOE ARCHIVES