Source: [THE HINDU], Thursday, June 25, 1998 Pg: 14 :: Col: d



Human casualties of a nuclear bomb

By C. Rammanohar Reddy



After the immediate effects of a nuclear explosion
(described in the first part of this article) the
delayed effects emerge. The main delayed effects are
firestorms and a nuclear fallout.

* Firestorms: The fires set off by the initial blast
coalesce and become huge firestorms. In Hiroshima, these
``super-fires'' developed 20 minutes after the explosion
and covered an approximately circular area with a radius
of about 2 km. Due to the high heat levels, these fires
are accompanied with high velocity winds with velocities
around 50 -80 km/hour. These winds suck in debris from
the surrounding areas which will add fuel to the
``super-fires''. With temperatures reaching several
hundred degrees centigrade, no one caught in the middle
of this inferno will be able to survive.

* Fallout: Soon after the initial explosion, when the
fireball touches the ground, a large amount of material
gets vapourised and is carried up into the atmosphere
where it mixes with the radioactive material of the
fireball. A cloud of radioactive dust is then formed,
which with the wind, can travel afar before falling back
to earth. If there is sufficient water vapour in the
atmosphere, fallout could coalesce and come down as
rain. Both Hiroshima and Nagasaki experienced this
radioactive ``black rain''. It is estimated that even if
just one per cent of the radioactive material that is
produced during the explosion returns to the earth as
fallout, then with a low yield 30 kiloton nuclear bomb
we are talking of a radiation dosage of 900 rads/hour -
anyone exposed to this for more than a few minutes is
highly likely to die within a few days.

What is the scale of devastation that these primary and
delayed effects will cause if India and Pakistan use the
capabilities they acquire? The study estimates the
number of people who will die if a small bomb of 15
kilotons (the kind used on Hiroshima) is exploded over a
large South Asian city at an altitude of 600 metres.

Mumbai is chosen in Dr. Ramana' s exercise. But the
fatalities will be much the same whichever the city in
India or Pakistan is subjected to a nuclear attack. The
common characteristic of all large cities in the
sub-continent is their huge population densities, which
makes them prone to a large number of casualties.

Such an explosion will generate a shock wave with
overpressure of 10 pounds per square inch or more over a
radius of 1.2 km. Within this region, brick buildings
and older concrete structures will collapse. People in
such buildings will be killed, so also those caught in
the midst of flying debris. Firestorms will develop over
a radius of 1.4 to 2 km. It is virtually impossible for
people caught in the middle to survive. In the
over-crowded South Asian cities, the number of such
fatalities will surely be very high. And if a bomb is
dropped over a coastal city of either India or Pakistan,
the incidence of the radio-active black rain will be
that much higher.

Casualties: The estimate of the number of people who
will die in Mumbai under a Hiroshima kind of bomb varies
within a small range depending on what methodology is
used. But one thing is common to them. The number of
fatalities will be huge and run into lakhs.

Dr. Ramana makes three estimates using three different
methodologies. The first methodology uses extrapolation
of the casualties in Hiroshima. The second assumes that
the main cause of death will be shock wave and the winds
that are associated with the blast. And the third
estimate is based on the assumption that it is the
firestorms which will be the main cause of fatalities.
All these lead to roughly comparable results for small
yield weapons. However, for larger weapons, such as the
thermonuclear weapon that India is believed to have
tested on 11 May 1998, the effects of the firestorms
would dominate.

With a population density of about 20,000/sq.km. in a
city, about 1.50-2 lakh people are likely to die when a
15 kiloton bomb is exploded. In the more crowded parts
of Indian and Pakistani cities, population densities
could well reach 100,000 per sq. km. This would lead to
7 to 8 lakh deaths for the same weapon.

What we are talking about is a number of fatalities
which is equivalent to the entire population of a
medium-sized town. If the weapon used has a yield of 150
kilotons, as would be the case for even a ``small''
thermonuclear weapon, these estimates go up by a factor
of 5 or 10 - i.e. the number of fatalities would be in
terms of millions not lakhs.

The casualties described here are the immediate deaths.
There are also the deaths due to leukemia and tumour
cancer that will emerge later. And in many cases genetic
mutilation will take place in the descendants of the
survivors.

The findings of this important study are terrifying
enough to wake the political class in both countries
from their nuclear reverie. This is the catastrophe that
could follow from the nuclear adventure that first the
Government of India and then the Government of Pakistan
have decided to subject their people to.

(Concluded)


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