Geoscience Reference
In-Depth Information
at its worst, an HILF event could result in such widespread damage to the fabric of our techno-
logical society that it would result in the end of the modern world as we know it.
What is generally referred to as an EMP is a deliberate detonation of a nuclear device at a
high altitude, roughly defined as somewhere between 24 and 240 miles, or 40 and 400 kilomet-
ers, above the surface of the earth. Nuclear detonations of this type have the potential to negat-
ively affect electronics, and electrical power grids, along their line of sight, covering huge dis-
tances on the order of an area 1,500 miles (2500 kilometers) in diameter, which would corres-
pond to a circular area stretching roughly from Quebec City in Canada down to Dallas, Texas.
Similar in many respects to EMP are “solar super storms,” which also have the ability to
severely affect electronics and electrical power grids. Though it may appear to the naked eye
that our sun is the one thing in our world that we can depend upon to be there day after day,
things are not always as they appear. It turns out that our sun is not nearly as consistent as it ap-
pears to the eye, having an ever-changing surface that is in a constant state of flux. There are
periods when the sun's surface is quite active, with fluctuating sunspots and intermittent
“coronal mass ejections” (CMEs) in which massive amounts of high-energy charged particles
are launched from the surface of the sun and hurtle through space at tremendous velocities. The
more active of these periods are referred to as “solar maximums.” It is when a CME is
launched toward our planet, and massive high-velocity charged particles from the sun impinge
upon the earth's ionosphere, that we experience a geomagnetic storm, the largest of which are
referred to as “solar super storms.” The relatively quiet periods of diminished solar activity are
referred to as “solar minimums.”
In relatively recent history, our planet has been subject to both solar super storms and high-
altitude nuclear tests. In all recorded cases, our civilization has survived these types of events.
However, our modern society is increasingly dependent upon microelectronics, the use of an
ever-increasingly complex and widespread electrical power grid, electronic telecommunica-
tions, and electronic data storage devices, all of which are highly sensitive to electromagnetic
disturbances such as those resulting from significant EMP events. Scientists, engineers, and
strategic government planners have recognized the serious nature of these threats to our society,
and have spent a great deal of time analyzing their extents, including studying past events as
well as developing simulated EMP apparatus to test the effects of EMP and geomagnetic
storms on modern electronic components and systems.
Studies include the effects of aboveground nuclear tests performed before the Partial Nuc-
lear Test Ban Treaty went into effect in October 1963, as well as the effects of geomagnetic
