Agenda - City of Santa Monica

Damage and injury are caused not only by the outward expansion phase of the wind
and pressure, but also in the opposite direction when the air is rushing back to fill the
vacuum. It is believed that an ordinary California home would be destroyed at about 1.5
to 2 psi, often 2 to 5 miles from the detonation.
Thermal Radiation
Thermal radiation is a burst of intense light and heat. This phenomenon can initiate fires
as well as produce casualties. A one-megaton explosion can produce flash-blindness
up to 13 miles on a clear day, or 53 miles on a clear night. Thermal radiation can cause
skin and retinal burns many miles from the point of detonation. A one-megaton
explosion can cause first-degree burns at distances of approximately 7 miles, seconddegree
burns at approximately 6 miles, and third- degree burns at approximately 5 miles
from ground zero. Detonation of a single thermonuclear weapon could cause many
thousands of burn casualties.
Initial Radiation
Initial radiation is defined as the radiation emitted during the first minute after
detonation, comprised of gamma rays and neutrons. For large yield weapons, the
range of the initial radiation is less than that of the lethal blast and thermal radiation
effects. However, with respect to small yield weapons, the initial radiation may be the
lethal effect with the greatest range.
Fallout
Fallout is produced by surface debris drawn into and irradiated by the fireball, then
rising into the atmosphere and eventually returning to earth. When a nuclear detonation
occurs, fission products and induced radioactive material from the weapon casing and
debris are pulled up into the fireball and returns to earth as fallout. A source of ionizing
radiation, fallout may be deposited miles from the point of detonation and thus affect
people otherwise safe from the other effects of the weapon. The radiation danger
associated with fallout decreases as the radioactive material decays. Decay rates
range from several minutes to several years.
Electromagnetic Pulse (EMP)
An Electromagnetic Pulse is an intense electric and magnetic fields that can damage
unprotected electronic equipment. This effect is most pronounced in high altitude bursts
(above 100,000 feet). Surface bursts typically produce significant EMP up to the 1 psi
over-pressure range, while air bursts produce somewhat less. No evidence exists
suggesting that EMP produces harmful effects in humans.
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