Border Tunnels, Part 5
How To Detect Tunnels.
Sometimes it is good to help people understand exactly what
can be done to solve a problem. This can be especially good when
the opposition is reading the same book. In the present case,
all the smugglers in "Tunnel Land" can read the following
and be warned.
Let’s examine some technology from World War Two or even
from before World War One and see how it can apply to detecting
tunnels along the border. And let’s not worry about the
simple tunnels linking to existing storm drains but instead look
at the really sophisticated ones costing tens of millions of dollars
There are two general methods for finding such tunnels using
seismic activity. While there are other tunnel detection methods
available only muon detection (discovered in 1911 and used by
that 12 year old boy to find tunnels) comes close in accuracy
and effectiveness as a persistent surveillance mechanism.
If one installs seismic detectors within the “No Man’s
Land” along the built up areas of the border, it is possible
not only to detect the digging noises of tunnel construction but
the distant removal of the dirt and its transport to a dumping
Digging noises can be masked to some degree by changing the digging
method. Low frequency digging noises – the thump, thump,
of a shovel or pick – can be detected at a quarter mile
in hard earth. If higher frequency tools are used then the sound
is quickly absorbed and detection at distance is made more difficult.
Because no tunnel has been built with its southern tail longer
than 2,000 feet below the border, the detection range for tunnel
construction probably need not exceed 50% more than that or 3,000