AFLM,

You said "A low yield 1 Kt explosion would typically kill around 20,000-30,000 (blast and fall out) people in a high density population centre with many suffering severe burns."

I would expect this to be an exeptionally large number and I cannot be support it with the data you have presented. Even using the numbers from Japan, which are way too high for an American city, it would be hard to justify 20 to 30,000 deaths. Using the major damage radius of .5 miles for a 10 kt blast we find .79 square miles of major damage. For the 1 kt blast a radius of about .2 miles is .13 square miles of damage. Expect 4 times the area, so this is on the high end of Hiroshima (a 16 kt blast) using the 10kt number and way too high for Nagasaki (a 21 kt blast).

These are also for air blasts over tightly packed areas of poorly constructed (for protection from air blast) structures. Many (some estimates suggest 50%) of the deaths in these areas were from fire (see the effects of the firebombing on the Japanese cities. The nearest survivor was in a concrete building only 560 feet away (total about 2000 feet from 16 kt). For a ground blast in a major US or UK city like New York the effects would be far less.

Fallout deaths would depend largely on the sheltering, rescue and evacuation efforts taken after the blast. The fallout deaths in Japan were largly caused by a total lack of understanding of the problem by the residents and the government.

Respectfully,

Jerry