XPLOSIONS

In considering the devastation in the two cities, it should be
remembered that the cities' differences in shape and topography
resulted in great differences in the damages. Hiroshima was all on
low, flat ground, and was roughly circular in shape; Nagasaki was much
cut up by hills and mountain spurs, with no regularity to its shape.

In Hiroshima almost everything up to about one mile from X was
completely destroyed, except for a small number (about 50) of heavily
reinforced concrete buildings, most of which were specially designed to
withstand earthquake shock, which were not collapsed by the blast; most
of these buildings had their interiors completely gutted, and all
windows, doors, sashes, and frames ripped out. In Nagasaki, nearly
everything within 1/2 mile of the explosion was destroyed, including
heavy structures. All Japanese homes were destroyed within 1 1/2 miles
from X.

Underground air raid shelters with earth cover roofs immediately below
the explosion had their roofs caved in; but beyond 1/2 mile from X they
suffered no damage.

In Nagasaki, 1500 feet from X high quality steel frame buildings were
not completely collapsed, but the entire buildings suffered mass
distortion and all panels and roofs were blown in.

In Nagasaki, 2,000 feet from X, reinforced concrete buildings with 10"
walls and 6" floors were collapsed; reinforced concrete buildings with
4" walls and roofs were standing but were badly damaged. At 2,000 feet
some 9" concrete walls were completely destroyed.

In Nagasaki, 3,500 feet from X, church buildings with 18" brick walls
were completely destroyed. 12" brick walls were severely cracked as
far as 5,000 feet.

In Hiroshima, 4,400 feet from X, multi-story brick buildings were
completely demolished. In Nagasaki, similar buildings were destroyed
to 5,300 feet.

In Hiroshima, roof tiles were bubbled (melted) by the flash heat out to
4,000 feet from X; in Nagasaki, the same effect was observed to 6,500
feet.

In Hiroshima, steel frame buildings were destroyed 4,200 feet from X,
and to 4,800 feet in Nagasaki.

In both cities, the mass distortion of large steel buildings was
observed out to 4,500 feet from X.

In Nagasaki, reinforced concrete smoke stacks with 8" walls, specially
designed to withstand earthquake shocks, were overturned up to 4,000
feet from X.

In Hiroshima, steel frame buildings suffered severe structural damage
up to 5,700 feet from X, and in Nag