Fifty seismic stations around the globe--previously used only to
feel the ground for natural ground-shaking events-have been rewired to also
sense vibrations from underground blasts. Over 120 other earthquake stations
can be called on to clarify unclear readings. "Seismic systems,"
says Lay, "will be the workhorse to detect [nuclear] events."
The ears of the system are under construction. Sixty listening stations
will dot the continents to hear for telltale rumbles in the air. They will
sense the bass kicks from blasts called infrasound, so low they are beneath
the human range of hearing. Undersea listening posts have begun to feel
for shock waves from nuclear explosions in the world's oceans. Four new
hydroacoustic stations will join the seven already being used by the US
Navy to track ocean impacts of missiles.
The nose of the sentinel is also under construction--80 refrigerator-sized
boxes that will sniff the air for radioactive particles and gasses. At the
slightest whiff of the unmistakable nuclear odor, these radionuclide detectors
will send the alarm to the nerve center.