rey eee ieee pees
SECRET——-AESTAIGPER-DATAD,ceKIeopies
AOA? 7
APPENDIX CG
CONCEALMENT AND DETECTION OF
NUCLEAR TESTS UNDERGROUND
Harold Brown and Hans A. Bethe
I.
General
To provide proof by acientific means the
i rs
iets FTen es, ge
=a
?
*
—
method is the seismic.
woh Maa ~e
—_—__—_
Such an explosion provides no electromagnetic signal, and the
acoustic signal if it exists at all will be so muffled and distorted that
it will not be characteristic even at a distance of a few hundréd miles,
No activity is released into the atmosphere, so that the only detection
7Vege ys Be atl
T
Complete containment of a test explosion underground, though
devised as a method for making testing easier by eliminating fallout,
may also serve as the most effective method of concealing the existence
of tests, and may makeit very difficult to gather effective proof that,
such teste have been carried out in violation of a suspension agreement.
residual activity from the explosion must be located underground and
sampled.
wr
ee
+F,
taf.
er
ect
.
. we .
¥
t
a
K-kp- (AS 4-5
pote
SLGRBEYTRESTRIGI
s
oP
shot could not be distinguished from those tnoved by past earth motions,
and fissures were present both before and after. Most observers at a
distance of 2-1/2 miles felt no earth shock. This is due principally
to the absence of hard rock between the source and the observation
point. (lt is possible that an underground shot will create less disturb ance above ground than an earthquake of the same seismic magnitude,
»
inconsistent with the results of a small earthquake; rocks moved by the
raeas
The only such shot carried out in this country which caste any
light on such procedures is the Rainier shot of Operation Plumbbob.
This was 1.7 KT in yield, and was buried 800 feet from the nearest
ground surface, in volcanic tuff. About 1% of the energy appeara to
have gone into the seismic wave, producing a magnitude 4.2 earthquake
indication on seismographs a few hundred miles distant from the shot.
Accelerometers indicate that the top of the mega under which the device
was located moved up about a foot and then fell back again. Rocks on
top of the mesa were displaced somewhat, and some were rolled down
the side, but the appearance of the surrouridings after the shot was not
.
Moe ATERlet
item
7 fees “Tybee pee I POS ser rhea. ey UN, eek Lage 4 a ee rage bo
Results from Rainier Test
er .
at
L204 Peto? / ZL
py “2c __NLEDate hed
Authority
+
a”
ak
ce —
DECLASSIFIED
tee
COE ee
YW.