Images de page
PDF
ePub

Co-ordination with the WMO proved to be essential not only prior to starting data exchange, but also during the actual exchange. Extended co-operation with the WMO/GTS will be needed to solve some of the major problems encountered in the GSETT.

Considering some of the shortcomings in the use of the WMO/GTS, the Group recommends that further efforts be undertaken to demonstrate that reliable communications for Level I data and bulletin transmission can be established using the WMO/GTS between all regions of the world. It is recommended that the Group maintain contact with the WMO in order to be kept informed of the possibilities for upgrading the existing WMO/GTS. A number of shortcomings in the use of the WMO/GTS could be overcome at the national level.

There is a need for additional testing of the WMO/GTS to improve the performance for the transmission of Level I data taking into account the recommendations given in this report. Particular emphasis should be given to those circuits not yet tested and those for which significant problems were noted in the GSETT.

8.4 Procedures at Experimental International Data Centres (EIDCs)

Operation of the three Experimental International Data Centres represented a substantial undertaking. These efforts produced a great deal of valuable data and experience which was not previously available. In a number of aspects, the testing of the EIDC procedures during the GSETT can be said to have been more successful than might have been anticipated, however, several problem areas were also encountered.

The automated procedures at the EIDCS for handling messages from the WMO/GTS communications channels worked well, although some problems were caused by the lack of strict adherence to established Level I message formats. The archival systems at the EIDCs were able to accommodate the large volumes of Level I data without problems.

The principles and algorithms for data analysis were not standardized at each of the EIDCs, and this resulted in differences in the seismic bulletins generated at the three centres. A bulletin reconciliation experiment conducted during the final two weeks of the GSETT improved the overall bulletin quality and showed the necessity of timely co-ordination between such data centres.

The data retransmission procedures were sometimes too slow to collect the data to allow inclusion in the event bulletin analysis on the schedule adopted. Since the schedule adopted for the GSETT is significantly slower than that called for in CD/448, more timely submissions of Level I data and other improvements in procedures are mandatory.

The GSETT can be considered fully successful in the sense that many of the proposed procedures for the handling of Level I data proved to be workable and practical. The performance of the EIDCs improved during the GSETT as some problems were noted and corrected. This clearly demonstrates the need for additional technical and practical tests of the envisaged system of international seismic data exchange.

It is necessary to re-examine the numbering system of the Level I data messages to develop methods to ensure stricter adherence to the prescribed

formats and to improve the definition and encoding of analyst comments so that they can be incorporated into the automated data analysis at IDCs.

Methods for improving communications between data centres must be adopted. Procedures must be developed to co-ordinate retransmission requests from IDCs, and conduct this function on a more timely basis than during the GSETT.

The data analysis procedures must be improved and relevant computer programs developed. These procedures and computer programs need to be tested and standardized between data centres. In addition, common criteria must be developed for the manual interaction at such centres, e.g., with regard to accepting or rejecting events and incorporating analysts comments.

The format of the detailed Final Event Bulletin needs to be further developed, and procedures for providing complete Level I parameters and event identification parameters for all defined events should be improved.

It is essential for a global system that different IDCs provide the same results from their final analysis and that the number of unassociated observations are reduced as far as possible. While the GSETT provided valuable experience, much work remains to be done in this field. The Group recommends that the procedures for defining seismic events be further clarified and that the procedures for continuous exchange of information between data centres during the analysis be further developed and tested.

There is the need for additional testing of the procedures employed at International Data Centres taking into account the experiences gained in the GSETT and the recommendations in this report.

137. Department of State Report: U.S. Policy Regarding Limitations on Nuclear Testing, August 19861

Recent Developments

Shortly before this Special Report went to press, the White House announced that the United States and the Soviet Union agreed to have experts meet, without preconditions, to discuss issues related to nuclear testing. An initial meeting of experts was held in late July 1986 at Geneva.

As this report details, the United States has long sought a meeting with the Soviets to present our concerns about the verification provisions of the Threshold Test Ban Treaty (TTBT)2 and the Peaceful Nuclear Explosions Treaty (PNET).' This meeting of experts allows the United States to present its ideas and concerns to the Soviets and to hear Soviet concerns. The United States is ready to present and discuss our views on verification improvements in existing agreements which we believe are needed and achievable at this time. If we are successful in

1 Department of State, Special Report No. 150, August 1986. There are three appendixes. Appendix 1 is printed infra. Appendix 2, which is President Reagan's letter of March 7, is printed in Document 30. Appendix 3 is not printed here.

2 For the text of the treaty, see Documents on Disarmament, 1974, pp. 225–227. 3 Ibid., 1976, pp. 328–332.

addressing these verification concerns, we could move forward on ratification of these two treaties.

A Collective Security Issue

The maintenance of a strong nuclear deterrent has for four decades ensured the security of the United States and the freedom of our allies and friends. Therefore, while a comprehensive test ban remains a long-term objective of the United States and while we are actively investigating technologies that could one day reduce and ultimately eliminate our dependence on offensive nuclear arms for our security, nuclear weapons will remain the key element of deterrence for the foreseeable future. During such a period, where both the United States and our friends and allies must rely upon nuclear weapons to deter aggression, nuclear testing will continue to be required.

A carefully structured nuclear testing program is necessary to ensure that our weapons are safe, effective, reliable, and survivable. The directors of both the Los Alamos and Livermore national weapon laboratories have stated that, while nonnuclear tests sometimes detect problems with the nuclear component of warheads, the most serious problems with the nuclear weapons stockpile are only revealed and solved by actual nuclear testing. Even a seemingly minor modification in a weapon design could seriously undermine confidence in the weapon's effectiveness unless the modified design can be tested with a nuclear yield. Testing also allows us to take necessary steps to modernize our forces to counter the continuing Soviet military buildup, particularly in offensive nuclear capabilities.

The United States has long sought to achieve agreement with the Soviet Union on nuclear testing limitations that could strengthen security for all nations. In 1963, both sides ratified the Limited Test Ban Treaty, which prohibits nuclear explosions in the atmosphere, outer space, and under water. The LTBT also prohibits the release of radioactive debris outside the boundaries of the state conducting a nuclear explosion. In 1974 and 1976, respectively, the United States and Soviet Union signed the Threshold Test Ban Treaty and Peaceful Nuclear Explosions Treaty. These treaties prohibit underground nuclear explosions having a yield that exceeds 150 kilotons. Neither side has ratified the TTBT or PNET, but each has stated that it would respect the 150 kiloton limit.

Verification Problems and Soviet Violations

The United States is not currently seeking ratification of the TTBT and PNET because we cannot effectively verify Soviet compliance with the 150-kiloton threshold on underground nuclear explosions. The remote seismic techniques we must rely on today to monitor Soviet nuclear tests do not provide yield estimates with the accuracy required for effective verification of compliance. Nor will the treaties' verification provisions solve this problem. The TTBT itself provides only for an exchange of data. This data would be of limited value in verification and, in any event, cannot be independently validated by the U.S. Government.

* For the text of the Treaty, see Documents on Disarmament, 1963, pp. 291–293.

This means, for example, that we would have no way of knowing whether the Soviets were providing data for all geophysically distinct testing areas. Yet if the Soviets withheld such knowledge from us, they could conduct high-yield tests in excess of 150 kilotons that, from the perspective of a seismic observer outside Soviet boundaries, could appear to fall within the 150 kiloton limit.

These verification provisions of the PNET Protocol would not resolve the problem of TTBT verification because they are not applicable to weapons tests. They would permit mandatory on-site inspection only of peaceful nuclear explosions—and then only in very restrictive circumstances. Specifically, onsite inspection is mandatory only for a group of explosions whose aggregate yield exceeds 150 kilotons. In fact, since 1976, the Soviets have not conducted any group nuclear explosions of the size which would have required them to permit such inspection. Thus, even if we were to ratify the treaties and implement their verification provisions today, our concerns regarding Soviet compliance with the TTBT would not be resolved.

The verification deficiencies have become a matter of great concern in light of the pattern of Soviet noncompliance with existing arms control agreements, including existing limitations on nuclear testing. As stated in the President's December 1985 "Report to Congress on Soviet Noncompliance With Arms Control Agreements," the Soviet Union's testing practices have resulted in the release of radioactive debris and caused radioactive matter to be present outside the Soviet Union's territorial limits in violation of its legal obligation under the LTBT. The report notes that Soviet venting has occurred on numerous occasions. In his 1984 report, the President concluded that "while the available evidence is ambiguous, in view of ambiguities in the pattern of Soviet testing and in view of verification uncertainties, and [while] we have been unable to reach a definitive conclusion, this evidence indicates that Soviet nuclear activities for a number of tests constitute a likely violation of legal obligations under the TTBT." In his 1985 reports the President reiterated this concern, finding “that Soviet nuclear testing activities for a number of tests constitute a likely violation of legal obligations under the TTBT of 1974. . . .”7

U.S. Presidential Initiatives

President Reagan has long advocated a dialogue with the Soviet Union to arrive at the required improvements in monitoring procedures for effective verification of the TTBT and PNET, which are the necessary first steps if there is to be progress in the area of nuclear testing limitations. The United States has taken the following initiatives:

5

On several occasions in 1983, the United States unsuccessfully sought to engage the Soviet Union in discussions on verification improvements to these treaties.

In September 1984, the President proposed, in an address to the UN General Assembly, that the United States and the Soviet Union find a way for Soviet

Ibid., 1985, pp. 935-953.

6 Ibid., 1984, p. 39.

1 Ibid., 1985, p. 952.

[ocr errors]

experts to come to the U.S. nuclear test site and for our experts to go to the Soviet test site to measure directly the yields of nuclear weapons tests. In July 1985, the President invited Soviet experts to come to the U.S. test site to measure the yield of a U.S. test with any instrumentation devices they deemed necessary for measuring yield. There were no conditions or requirements for a reciprocal visit. The President's purpose was to begin a process to build confidence and cooperation between our nations regarding limitations on nuclear weapons testing.

In December 1985, the President proposed to General Secretary Gorbachev that U.S. and Soviet experts on nuclear testing limitations meet in February to discuss our respective verification approaches and to address initial tangible steps to resolve this issue.

The President's Proposal of March 1986

In his most recent initiative, on March 14, 1986, the President urged the Soviet Union to begin bilateral discussions to find ways to reach agreement on essential verification improvements of the TTBT and PNET.10 The President provided General Secretary Gorbachev with a technical description of a specific method known as CORRTEX, which is an accurate method for measuring the yield of a nuclear explosion (see Appendix 1). The President also proposed, on a unilateral basis, that Soviet experts visit our Nevada test site in April to discuss verification methods, examine the CORRTEX system more closely, and monitor a planned U.S. nuclear weapon test. The President stated that if the United States and the Soviet Union could reach agreement on the use of an effective verification system incorporating CORRTEX, the United States would be prepared to move forward with the ratification of the TTBT and PNET.

The President's proposal offers an opportunity for the Soviets to demonstrate that they take testing limitations seriously and recognize that compliance with such agreements is necessary. The United States must stand by its standard of effective verification with respect to the TTBT. Anything less would harm U.S. security interests, undermine our ability to demand effective verification in other arms control areas, and undercut the objectives of the TTBT.

Comprehensive Test Ban

A Comprehensive Test Ban (CTB) remains a long-term objective of the United States. As long as the United States and our friends and allies must rely upon nuclear weapons to deter aggression, however, some level of nuclear testing will continue to be required. We believe such a ban must be viewed in the context of a time when we do not need to depend on nuclear deterrence to ensure international security and stability and when we have achieved broad, deep, and verifiable arms reductions, substantially improved verification capabilities, expanded confidence-building measures, and greater balance in conventional

8 Ibid., 1984, p. 692.

9 Ibid., 1985, pp. 443-444.

10 Document 35.

« PrécédentContinuer »