TABLE OF CONTENTS
THE PROBLEM
FOREWORD
CONCLUSIONS
DISCUSSION
I. CURRENT SOVIET NUCLEAR WEAPONS TECHNOLOGY
Applicable to Programs Other Than ABM
Applicable to ABM Programs
TABLEOVIET HIGH ALTITUDE TESTS
IL IMPACTHRESHOLD TEST BAN TREATY ONPROGRAMS
on Nuclear Toting
on Military Programs Other Than ABM
C Impact on ABM rrograrm
III. US DETECTION CAPABILITIES
Poge
.. 1
. 4
Capabilities of the AED_S
of Intelligence Sources
a Vfelation
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THE POSSIBILITY OF SOVIET COVERT VIOLATION
THE IMPACTHRESHOLD TEST BAN TREATY ON SOVIET MILITARY PROGRAMS
the problem
To estimate the impacthreshold Test Ban Treaty oo Soviet military programs, with particular emphasis on its impact on Soviet ABM activities; to discuss the capabilities of US intelligence to monitorest ban: and to evaluate Soviet capabilities for covertlyit.
foreword
The Threshold Test Banonsidered in this estimate isin line with proposals under discussion in the US and abroad, but it does notpecific proposede assumeof the terms of the Partial Test Ban Treaty now in effect, which prohibits testing of nuclear devices in the atmosphere; beyond its limits, including outer space; underwater (including bothwaters and the highr in any other environment if such explosion causes radioactive debris to be present outside the territorial limits of the stale under whose jurisdiction or control such explosion is conducted. The Threshold Treaty considered in this estimate would add to the restrictions of the currentrohibition of anynuclear testeismic disturbance5 on tho Gutenberg-Richter scale. It is assumed that treaty language willethod byean magnitude for any particular event will be established, thus avoiding international disputes about the magnitude of reported events. It imposes no limitations on themedium in which the tests take place, or on the degree of decoupling employed. It provides no on-site inspection and no IftAO-
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tions. each participating nation will have to decide for itself whether any given seismic event of magnitude greater5 was causeduclear detonation andreaty violation.
conclusions
- a. we believe that for most of the soviet military developmentwhich we can foresee over the next fewhreshold test ban treaty would impose no greater restrictions than those alreadyby uic partial test ban. however, the relationship between the yield of underground explosions and the resulting seismic readings is uncertain at best, and can be greatly altered by decoupling. tho soviets might therefore still testide range of yields, depending on how far they were willing to risk violating the treaty and to support the cost and effort of decoupling. practically speaking, we believe
they could develop weapons yielding
by scaling up from lower yield tests which wouldair chance of not producing seismic readings they might con-
ceivably develop tn weapons with yields
by expensive decoupling methods. )
with respect to abm weapons, we think there is about an even chance that the soviets have already
if they have not already donehreshold treaty
existing soviet weapon technology would support it either without further testing, or with tests that wouldeasonable chance of not exceeding the threshold.
c. we believehreshold treaty would impose prohibitive restrictions, beyond those of the partial test ban. only for developing weapons which might need new warheads yielding
uic development of such weaponsufficiently high priority the soviets might conduct tests virtually certain to violate the treaty, in uic belief that the violation could not be proved against them. as few as one or two suchear could be of significant aid to their military programs. )
O
UNO
US Atomic Energy Detection System (AEDS) wouldcertainly detect all seismic events in theUSSRagnitude
5 or greater. Perhaps with help
it could probably discriminate between explosions and earthquakes occurring in most parts of the USSR, but there would stillewearspecially in the Kamchatka-Kuriles area, which could not be so identified. Such events would representtreaty violations, but itxtremely unlikely thatcould with certainty either confirm or denyuclear event had in fact occurred. )
a seismic event5 was identiBed as an explosion,almost certainly be nuclear in origin. Thus this evidence,with what might be available from intelligence sources,be sufficient, exceptew cases, to determine to theof the US government whether or not Uie explosion wasin origin. Evidence sufficient toorld forum thatwas nuclear could almost certainly be derived onlyinspection, which is not permitted by the Thresholdconsideration.
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discussion
i. current soviet nuclear weapons technology
past decade of increasingly sophisticated soviet testing of nuclearand weapons lias included8 series, two series of intensivend two years of testing underground since the partial testwas signed inn evaluation of the effects of aban treaty on soviet military programs must starteview ofnuclear technology developed through these tests and its relation toprograms.
a. technology applicable to programs other than abm
Development. the sovietsamily of thermonuclearresponsive to the present needs of their strategic attack andforces. soviet long range aviation and the bocket forces havenumber of older tn weapons in the low megaton range based on thethe tests conducteds and earlier. weapons based onest series probably began to enter stockpilend are nowin significant quantities, and will continue to be produced in orderolder weapons still in the strategic attack forces stockpile thesegenerally represent significant improvements over the entireand probably include some high yield (over ten mt) tndelivery by both uircraft and missiles.arhead
suitable for thes estimated to he now availableesult ot theests.
he soviets had6ariety of relatively largeweapons inwhich are probably still in stock-
pile in large numbers for tactical missile and rocket forces, for tactical aviation, for general purpose uses by the soviet navy, and for sam forces.esult ofests the soviets were able to develop fission weapons in the
i most of the newer
fission weapons entering the soviet stockpile in the last few years are probably these improved low-yield weapons,
rior to the partial test ban treaty the soviets had largely fulfilled their basic requirements for multimegaton tn weapons and for fission weapons. they may stillequirement for tn warheads in the submegaton and low megatonor thehis requirement can be fulfilled under tho partial test ban, and probably would be hdfilled before the soviets accededhreshold treaty. under the partial test ban, the soviets have conducted tests yielding upt. some of the tests yielding aroundt and higher
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were probably directed toward development of TN weapons. Several tests yieldingT or less have been detected, especially during th* past year; these could have been oriented toward development of either fission or IN weapons. Some weapons based on the underground tests of tho last two years will probably start entering stockpile next year, and will be available for systems beingover the next several yean.
ffects Testing. Our analysis of Soviet tests provides very littleon Soviet programs to enhance the kill potential of nuclear weapons, or on the state of Soviei knowledge of the various kill effects of nuclear explosions. Most of tbe thermonuclear tests were held at Novaya Zemlya, where the Soviets were probably able to Instrument only for the basic diagnostic informationfor development of TN weapons. Most of the Soviet fission devices were tested at Semipalatinsk. we know little about the methods of testing there or the kinds of effects instrumentation employed.
he Soviets have conducted extensive tests of the effects of nuclear bursts on military equipment and structures. Although we cannot say how much the Sovieis may have learned about kill effects from their tests, they have clearly had ample oppmtuoity to discover the same important nuclear effects which we have discovered.
nalysis of Soviet publications and classified manuals shows lhat the Soviets have acquired effects data of sufficient scope and quality on air, surface,and underground bursts to be adequate for planning and executing most military operations. Unclassified articles show that they are aware of theradiation effects on electronic equipmentlthough we have no knowledge of the extent to which they may have explored these effects, we do have evidence that they arc aware of the vulnerability of US missile guidance systemi to them. The Soviets have also shown that they understand tbepulse (EMP) phenomena produced by nuclear explosions, and they may haveumber of low-yield surface tests to measure the EMP effect on military systems and communications equipment. Although the Soviets are probably aware of thelnerability of ICBMs and silos, it is doubtful that they have conducted tests of the surface EMP effects of high yield weapons.
the foregoing, we think tbe primary effect of the presentBan on Soviet weapons programs has been to prevent completeand effects testing in the atmosphere or space. Nevertheless, theobtain some rignificant data on these effects by simulatingspace environments in undergrnund
B. Technology Applicable to ABM Programs
Tests. Duringeries, the Soviets conductedof high altitude nuclear lests, near Sary Shagan. (Soe
Tliese testsoviet interest in assessing the capability of an ABM system to discriminate and track two or more targets approaching successively on nearly identical trajectories, bothadur blackout environment andormal atmosphere.2 events appear to have been conducted for the primary purpose of studying the effects on radar systems of blackouts created by high yield precursor hursts or by detonation of the interceptors own ABM warheads. Data relating to certain long range effects, suchP and TREE, may also have been collected. It is unlikely, however, that the tests involved devices which had enhanced radiation output.r that the Soviets were tesdng for the vulnerability of re-entry vehicles (RVs) to shock produced by surface absorption of loways.'
haracteristics of Certain Nuclear Weapons. Another portion ofest series involved the detonationroup of TN weapons in5 MT range. These weapons showed certain characteristics suggesting that theyew Soviet weapons design. One recent attempt toheoretical model exhibiting these characteristics ledesign that could produce anay output. Wc think it likely that the Soviets would realize the importance ofay effects for exoatmosphcric ABM weapons and could adaptesign accordingly. If such is the case, the Soviets Ihen couldeapon that wouldavs /
BM Deployment. For several years the Soviets have been constructing what we believe are ABM defenses.1 The missile most likely to be used in an
'A loway ouiput Is one ofilo-electron voltsay energy can be enlianeed. at tbe eipeose ol othery appropriate design of the weapon.ay energyevconsidered medium energy,ev ii high energy.ay energyev is often calleday.
'See, "Soviet Strategic Air and Madle Defend"ond footnotes thereto.
^
role in suchho Galoshalosh-type. Givendifficulties of identifying lethal warheadsloud ofoutside Ihe atmosphere, it Is desirable that an exoatmosphericemploy weapons with asill radius as feasible. Thb in turna nuclear warhead with improved kill capabilities, one way ofmight be throughays. One of the group of weapons describedpreceding paragraph appears highly suitable for use wilh tbe Galoshhave no evidence whatsoever that thb or any other of the group ofnuclear weapons is the Galosh warhead, nor indeed can we be suregroup of now nuclear weaponsNeverthe-
less, the apparent deployment of an expensivesystem employing exo-atmospheric interceptors argues that the Sovietsarheadarge kill radius, whatever mechanism may he used to achieve it.
consider'lions in the preceding paragraphs lead us to believe thatabout even fi,v- Sov:ian las'MfBOkfttflrJcthough wc thinkdid notomplete system in lWl-iaKt It is of course desirableABM warheads in their actual environment, butossible byfrom laboratory and underground test data to calculate the effects ofon various objects at various altitudes.
II. IMPACTHRESHOLD TEST BAN TREATY ON SOVIET MILITARY PROGRAMS
A. Limitations on Nuclear Testing
Degree of Risk Accepted. Because of variations in geological structure and In the propagation paths of seismic signals, nuclear explosions of the same yield may produce quite different seismic readings. Experimental evidence based on US tests and measurements indicates that the seismic magnitudeuclear test of known yield andiven medium may vary by upnits on the Gut en berg-Bid iter scale. As SO percent of tlie cases fall above andercent below the averagehot intended toeading5 on that scale would0 percent chance of exceeding thatountry desiringercent assurance of not exceeding5 limit would be limited to tests of about one-half the yield it might test with onlyercent assurance.
Testing Medium. Most detected SoviPt underground tests have taken place in.
ijLUIfc
1
t would be possible, without violating the Thresliold Treaty, to test indevicesould be tested in granite.
WeTeTfcve thai theave
had little experience In lusting underground in dry alluvium at yields above the low kiloton range. The USSR probably has alluvial deposits of sufficient depth, but we do not know whether the deposits are dry toepth as
would permit testing
iittij; be required.
that seismic effects from an explosion on the order of most of the time, be degraded through decouplingeading,ery large and costly cavity would
he Soviets could probably scale up from the devices they testedwith reasonable confidence, weapons having yields four or five tunesas the test devices Thus, we think that. prcAiding theyhance nf exceeding the threshold, the Soviets couldthey might develop
utilizing expensive decoupling
ecoupling. It tt poulblr that the Soviets would resort totechnique in which tbe nuclear explosion takes placearge cavern, thereby reducing the seismic disturbance. Decoupling at lower yields appears feasible, but to decouple larger yields so that they can be tested within3 becomes increasingly expensive and difficult. It has been estimated thativen seismic threshold one might test witheviceield up to as much asimes greater than could be tested withoutBut thisighly theoretical and obviously very uncertain estimate.ractical matter, il seems to us likely on the basis of present knowledge
hyJestEj
could,5
weapons with methods.
B. Impact on Military Programs Other Than ABM
t follows from what has been said abovehreshold Treaty would not seriously hamper Soviet development of small yield tactical weapons, low yield testing for special effects (enhanced or suppressed radiation for tacticalr acquisition of data on the vulnerability of components. Underreaty, though with some risk of violating it, the Soviets could also probably develop new or follow-on TN waiheads with yields
for their small-silo mrnllc systems, as well as for new naval rnusile systems.believe that for the tests needed to develop an entirely new warhead withSoviets would be forced either to resort to expen-
sive dwnrpimg. or. nwrv likely, toreater thanercent chanceest would5 seismic reading. Full-scale tests of high yieldor of silo hardness against nuclear weapons cannot be conducted under either the Threshold Treaty or the Partial Test Ban.
t is difficult even under the Partial Test Ban to conduct the tests
to develop new warheads yieldingThreshold
Treaty would add to these difficulties.
It may be that the Soviets will wish to develop new warheads oi sncn yieias ivhicli are hardened against US ABM weapons, or which can be used in their own ABM programs, or both. Apart fromthese possible requirements, we believe that the Soviets do not need to conduct such tests as would carry high risk of violating the Threshold Treaty.ests enabled them to develop multimcgaton weapons with acceptable yield-to-weight ratios for Long Range Air Forces and Strategic Rocket Forces, and to test effects of these weaponsegree compatible with military requirements.
C. Impact on ABM Programs
s stated above, we believe there is about an even chance that thealready developedwarhead.
If they have not already done so, aTreaty would not, in our view, makeevelopment impossible, as wc believe existing Soviet weapon technology would support it, either without further testing or with tests that wouldeasonable chance of not exceeding the threshold. The Soviets coulday lethality data applying toarhead from underground testing without violating the Treaty. We believe also that inests the Soviets acquired enough data on radar blackout effects to permit them to develop and deploy this weapon system. Although the Soviets would almost certainlyequirementull-yield exoatmospheric test of the system and for tests to acquire additional blackout data, this is already prohibited under the Partial Test Ban.
w;
this
ABM warhead with
rrhey mightrw
it, we believehrcshold Treaty would no! be afactor as long as the prospective warheads were in the submcgaton range. For the developmentew ABM warhead of this type in the multimcgaton range tbe Threshold Treaty wouldignificant limitation over the present treaty.
III. US DETECTION CAPABILITIES
ho ability of the US tohreshold Treaty and to detectinvolves establishmenteismic event has taken place and is5 magnitude, identification of such an event as natural or explosive in origin, and identification of an underground explosion as nuclear or conventional high explosive.ifferent, but related, problem is that oforld forum
of the validityS identificationeismic event5 in magnitudeuclear explosion.
A. Monitoring Copabilities of the AEDS
B. Capabilities of Intelligence Sources!
ntelligence resources of the USIB community could sometimes be useful in supplementing the AEDS analysis
I
t is also possible that changes in Soviet test locations or methods could degrade US intelligence capabilities. Although we would expect the Soviets
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io resort to such activity so far as practicable if they attempted clandestine testing, we do not believe they would be completely successful in eliminating intelligence indicators.
C.iolation
o criteria foriolation arc specified in any of the proposalshreshold Treaty.
We believe that in
general such prool could be demonstratedorld forum only by on-site inspection, which is not permitted under any form of the contemplatedat-.
IV. THE POSSIBILITY OF SOVIET COVERT VIOLATION
We have estimated above that the Soviets can meet most of theirrequirements for weapons development withouthreshold Treaty. If they foresaw testing requirements for military programs that would require consistent violation, they probably would not sign the treaty in the Grst place. We also believe they would not accede to tho treaty unless they thought it would be relatively advantageous to them, or at least not disadvantageous, Once they had enteredreaty, the Soviets probably would feel that the advantage to be gained from frequent violation would not be worth the political damage to their international position, providing these violations were proved against them.
It is clear, however, that the Soviets could gain significant advantages in weapons development from one or twoear which exceeded the threshold.
Original document.
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