the conclusion of an agreement on the complete and general cessation of nuclear weapon tests. The conclusion of an agreement making all nuclear weapon tests illegal would be a major contribution to the task of limiting the nuclear arms race and would, thereby, promote the further development and deepening of the process of international détente and the elimination of the danger of nuclear conflict. The delegation of the USSR made this Soviet proposal the subject of its statement in the Committee on 18 March 1976 in which it described its content and emphasized its great significance. 16 In accordance with the procedure recommended by the General Assembly (resolution 3478 (XXX)17), this proposal is being considered by a group of States outside the framework of the Committee on Disarmament, since not all nuclear States participate in its work.

Important steps toward strengthening international security and eliminating the threat of nuclear war are being taken by the Soviet Union in bilateral contacts and talks with the United States, which have resulted in agreements and understandings which are well known to members of the Committee. These agreements constitute an important part of international efforts aimed at preventing the use of nuclear weapons in international conflicts and the establishment of a system of genuine guarantees of international security.

In its pursuit of the aim of strengthening international peace and ensuring the security of peoples, the Soviet Union propounds the goal of renouncing the use of force and the threat of the use of force to solve controversial international questions. This principle has been reflected in a number of agreements between the USSR and other countries. It is contained in the Final Act of the All-European Conference.18 A report by Mr. Brezhnev, approved by the Twenty-fifth Congress of the Communist Party of the Soviet Union has the following to say on this question:

In order further to diminish the danger of war and to create favourable conditions for progress towards disarmament, we propose that a world wide agreement on the non-use of force in international relations should be concluded now. The States parties to it, including of course the nuclear Powers, would assume the obligation to refrain from the use of any types of weapons, including nuclear weapons, for the settlement of disputes among themselves. The Soviet Union is prepared to examine, together with other States, practical steps toward the implementation of this proposal.1

The conclusion of such a treaty would be of paramount importance for strengthening world peace and international security, and for prohibiting the use of all types of weapons, including nuclear and other weapons of mass destruction.

We hope that, during the summer session of the Committee on Disarmament, even greater efforts will be made by participants to create conditions in which the danger of catastrophic and devastating international conflicts will be eliminated.

Statement by the United States Representative (Martin) to the Conference of the Committee on Disarmament, April 22, 19761

In my statement today, I would like to address the question of a comprehensive test ban, the subject we are presently considering in informal meetings with experts. My Government's position on this subject can be summarized quite briefly. In the absence of a reliable, mutual prohibition, we believe that our nuclear testing programme serves as an important means of maintaining the effectiveness of our nuclear deterrent. However, as representatives of the United States have stated on several previous occasions, we would be prepared to give up whatever benefits exist in continued testing if this were done pursuant to an adequately verified agreement that provided reasonable confidence that other parties to the agreement were also giving up those benefits. Inability to reach a common understanding on verification measures capable of providing such confidence has, in our view, been the principal reason why a CTB has remained beyond our grasp. There is general agreement that seismic monitoring would be one of the essential means of providing confidence in compliance with a CTB. For this reason, my Government has expended substantial resources and effort to improving seismic verification capabilities. Document CCD/491, which my delegation is formally introducing today and which was outlined to members of the Committee during our informal meetings, reviews recent progress made in seismic verification research in the United States.2

The working paper describes the development and installation of new seismic systems, including the projected 13-station Seismic Research Observatory Network, which will add significantly to our existing data sources. Concurrently, we are developing a sophisticated data processing facility, located in Alexandria, Virginia, which we expect will enable a large volume of data from many sources to be applied efficiently and effectively to seismic research problems.

The working paper also reports on some encouraging developments from our research efforts. For example, it describes a new technique that could improve our understanding of the anomalous event problem. This technique appears promising but requires further evaluation. Another development mentioned in the paper is the completion of a model study of evasion problems. This indicated that a well-sited network of single stations within a given land mass could, within that area, reduce by a full order of magnitude the yield at which an evader could be confident of escaping detection. We are hopeful that the application of the new data resources and these new analytical techniques to the principal remaining problems of seismic monitoring will result in a further improvement in seismic verification capabilities.

1 CCD/PV. 704, pp. 19–25.

2 Ante, pp. 251-265.

However, the results of several comprehensive detection and identification studies, which were reported in the working paper, indicate that there are significant remaining limitations to seismic verification. This indication was confirmed by the presentation of experts from several delegations during the informal meetings. Because of these limitations, we do not presently foresee how a CTB verification system based solely on teleseismic means could provide adequate assurance that a party was not conducting a clandestine testing programme of military significance.

Differences of opinion were expressed by the experts this week on the seismic magnitude level at which nuclear explosions could be detected and identified with confidence. However, there was little disagreement that, below some level, the verification possibilities were exceedingly limited. Some delegations have nonetheless stated that any clandestine testing that might be possible under a CTB would not be of military significance. We cannot agree with this conclusion. It is noteworthy, in this connexion, that a significant number of United States nuclear tests during the last few years have had explosive yields of less than 20 kilotons. Tests at these lower yields could provide much fundamental information useful both for tactical and strategic weapons development. For these reasons, we believe that the effects of a testing programme carried out at yields that might not be identified by teleseismic means could indeed have considerable military value.

Some delegations have claimed that national technical means of verification other than seismic monitoring could facilitate verification of a CTB. We would agree that other methods of remote monitoring could, in principle, contribute to CTB verification. However, the value of such methods should not be overestimated, since they would have inherent practical limitations. For example, a determined evader might be able to disguise or avoid the characteristics of testing that such methods were intended to detect.

In view of the existing limitations of national technical means of verification, we believe that adequate verification of a CTB continues to require some on-site inspection. In many instances, on-site inspection would be the only means of providing conclusive evidence for example, through sampling for radioactivity-that a detected seismic event was a nuclear explosion rather than an earthquake or a conventional explosion. Thus, a verification system that included on-site inspection would provide not only a substantial deterrent to clandestine testing by increasing the risks that any significant violation would be discovered, but also a means of assuring confidence in the treaty régime in those cases where seismic methods may have misidentified earthquakes as explosions or presented ambiguous evidence concerning the nature of a seismic event.

Unmanned seismic observatories (USOs), sometimes called "black boxes," have also been suggested as a means of verifying a CTB. USOS could lower the threshold magnitude for detection and identification, improve the capability to locate events, and thereby provide additional

deterrence to a violation. However, they could not provide conclusive evidence that a seismic event was a nuclear explosion. Thus, USOS could make an important contribution to seismic verification of a CTB, but they are not the equivalent of, and should not be regarded as a substitute for, on-site inspection. Nonetheless, we believe it is important that further effort be devoted to the development of tamperproof, reliable, low maintenance USOS involving minimum intrusiveness, and also to evaluating the potential utility of such instruments to a CTB verification system.

The United States continues to regard international seismic co-operation as a promising component of a CTB verification system. We have in the past made a substantial amount of seismic information available internationally in an effort to promote greater understanding of how seismic data exchange could contribute to monitoring a CTB. In light of these efforts, we support the Swedish proposal that an ad hoc group of experts be established to examine the contribution that international seismic co-operation could make to the detection and identification of seismic events. We believe, however, that the project— which would be a major undertaking for the Committee-should be carefully conceived and that its terms of reference should be carefully formulated. In particular, we believe it should be made clear that the group's responsibilities are technical in nature. We further feel that it should not attempt to make judgments that would more appropriately be made by Governments such as an assessment of the adequacy of a given seismic monitoring system for verifying a CTB. We further believe that the study should be confined strictly to seismic means of monitoring. We look forward to discussions early in the summer aimed at reaching broad agreement on acceptable terms of reference for the study.

Recently it has become widely recognized that the problem of clandestine weapon testing is not the only CTB verification issue still unresolved. There is, in addition, the critical question of whether, under a CTB, an adequately verifiable accommodation for PNEs can be worked out. In CCD/456, my Government took the view that, if PNES were to be accommodated under a CTB, a verification system would have to be devised that would provide adequate assurance that weaponsrelated benefits were not being acquired from nuclear explosions carried out ostensibly for peaceful purposes. To achieve that objective, a control system, at a minimum, would have to prevent the testing of a new weapon concept, the substitution of a stockpiled weapon for the "PNE" explosive to verify its performance, and the carrying out of nuclear weapons effects studies.3

In CCD/481, the delegation of Sweden maintained that it was possible to deal with the problem of PNE accommodation by expert observation and on-site inspection. They discussed two different approaches to solving the problem.

Documents on Disarmament, 1975, pp. 247-254.

One possibility could be to monitor the composition of radioactive debris produced at the explosion site. Thereby one could check that nuclear devices of well-known design were not replaced by grossly different constructions. Another, and in our view quite effective, way would be to make sure, by expert inspection, that the explosions are not used for what is called diagnostic measurements of the explosion itself in its very early stages. In this way it could, in our view, be possible to reduce any weapon development advantages to a minimum.*

My Government cannot agree that the two approaches suggested by Sweden would meet the requirement of achieving adequate assurance that weapons-related benefits were not being derived from peaceful explosions. Even if it were possible to demonstrate-by radiochemical analysis or any other means that the device used was of a "well-known design," this would provide no assurance that the explosion was not contributing useful information to a weapons programme. In addition, detailed diagnostic measurements are not essential for deriving important weapons-related information.

Further consideration is needed of the difficult and complex question of whether, under a CTB, an adequately verified accommodation for PNES can be achieved. No satisfactory solution to this problem has yet been found.

A question that has recently surfaced as a significant issue in CTB discussions is whether the adherence of all nuclear-weapon States, or all nuclear-testing Powers, would be required before a CTB could enter into force. In light of the serious security implications of nuclear weapons testing, the question of participation would obviously have to be addressed in considering any CTB proposal. Among the factors that would presumably be taken into account in arriving at a position. on this matter would be a testing State's perception of its own nuclear capabilities and testing experience relative to the nuclear capabilities and testing experience of other testing Powers. However, we question the desirability and timeliness of taking a position on the participation issue in the abstract, before resolving the principal problems holding up a CTB-namely, verification difficulties, including PNEs. Once they are resolved, several options would be available. These include: an agreement that would enter into force upon the adherence of all nuclear Powers; a limited duration agreement not requiring adherence by all nuclear Powers that would provide for review and extension; and an unlimited duration agreement not requiring adherence by all nuclear Powers but containing a provision for withdrawal in the event that treaty parties considered their supreme interests to be jeopardized. For its part, the United States has not made a determination whether a CTB should require the participation of all nuclear Powers before it could enter into force.

During the major portion of this week the Committee has considered, in the words of the sponsors of the informal meetings, the "remaining obstacles to a comprehensive test ban agreement." I would

'Ante, p. 141.