raised by the implementation of a verifiable test-ban treaty. It did not provide us with an answer to the arguments against a test ban, to which I referred earlier. Unfortunately, past experience with moratoria, even applied by only three parties, has been that they ended in a breakaway, leading to an explosive outburst of new series of tests, rapidly making up for tests temporarily renounced. As a matter of fact, in August it will be 25 years ago that the Soviet Union, the United States and the United Kingdom ended a moratorium on nuclear tests, respected up to then, in a spectacular way and turned it into its reverse. We must conclude that moratoria can never be a substitute for a bilateral or a multilateral agreement on a comprehensive test ban, laying down the details of scope and verification. The question with which we are faced is how to reconcile two positions. One is: "test ban first, disposal of nuclear arms later", and the other: "disposal of nuclear arms first, test ban later".

In the past, suggestions have been made at the Conference on interim measures, in particular on a threshold treaty. I do not now wish to enter into the merits and the drawbacks of the idea of a threshold treaty, but I wish to point out the risk that, if such a treaty were a multilateral treaty, open for accession by nonnuclear-weapon States, it might provide those countries with legal, or at least moral, arguments for taking up testing under the threshold level set by the treaty. Since a multilateral CTBT ought to strengthen the non-proliferation régime, we think countries should beware of interim régimes on a multilateral basis. A CTB should be truly comprehensive, including a ban on so-called peaceful nuclear explosions.

My authorities have reached the conclusion that any interim approach towards the goal of a multilateral CTB should involve only the States that are responsible for the bulk of nuclear test explosions. Such an interim approach should furthermore aim at meeting to the extent possible all objections that have thus far come to light.

It is with these considerations in mind that the Netherlands has reached the following conclusions on this point.

First, we wish to encourage the United States and the Soviet Union-I repeat— to continue the discussion on verification issues that have just started. These countries should, as soon as possible, reach agreement on terms that permit the ratification of the threshold treaties (TTBT and PNET). If the Soviet Union were to allow the United States to undertake some calibration measurements in the vicinity of relevant Soviet test sites, this will certainly be conducive to reaching such agreements. The President of the United States made an offer to the Soviet Union last year for Soviet scientists to acquaint themselves with the measuring techniques of the Corrtex type. We still hold the view that the Soviet leaders should positively respond to this offer, thus opening the door to the ratification of these treaties.

5 Documents on Disarmament, 1961, pp. 337-348; 355.

"I.e., the so-called Threshold Test Ban and Peaceful Nuclear Explosions Treaties. The texts of these treaties and their protocols may be found, respectively, in Documents on Disarmament, 1974, pp. 225–229 and ibid., 1976, pp. 328–348.

We are encouraged by the admission to the Soviet Union of a group of American seismologists, to which I referred earlier. We understand they have installed measuring devices near Semipalatinsk. Although these devices are far away (150 km) from the actual test site and it is not clear whether they will continue to function once the Soviet Union will resume its nuclear tests, we do hope this new event can be considered as signalling an encouraging change in the Soviet position on on-site inspection in general.

Second, we submit that, if the two major nuclear Powers were to agree progressively to reduce their nuclear arsenals, they should simultaneously and in relation to these reductions agree to reduce nuclear tests, both quantitatively and qualitatively. Such a formula dealing with nuclear tests would be a natural corollary of the bilateral arms control negotiations taking place elsewhere in this town. Our proposal links fewer nuclear weapons to fewer nuclear tests and, depending on the scope of the arms agreements, to no tests for new types of nuclear weapons.

I hasten to stress that an arrangement of this kind would in no way obviate the necessity of the speediest conclusion of a comprehensive test-ban treaty (CTBT). It would in no way affect the multilateral process either in the Conference or in the General Assembly or elsewhere.

The two major nuclear Powers could at any time make the qualitative jump to a CTBT. But, we think that the Conference should not wait for such a jump to be made. It is in fact high time that we agreed on the procedure to be pursued in order to start the necessary work. My delegation believes that the Western proposal (CD/521) provides an excellent basis for work to be resumed in this complex area and we hope that consultations on the basis of that text will in fact soon prove to be successful.

The Netherlands will continue its efforts for an early conclusion of a CTBT prohibiting all nuclear explosions for all times. Our proposals, our suggestions, today should be seen in that context.

135. U.S. Statement on the Conclusion of the Thirtyfirst Session of the U.S.-Soviet Standing Consultative Commission, July 30, 19861

The U.S.-U.S.S.R. Standing Consultative Commission met in Geneva today, completing a special session of the commission, the second session of 1986 and the 31st since its establishment. The U.S. and Soviet commissioners reaffirmed that the next session of the commission would begin in the fall of this year in Geneva. The commission was established by the Treaty on the Limitation of

1 Department of State Bulletin, October 1986, p. 18.

Anti-Ballistic Missile Systems concluded by the United States and the U.S.S.R. on May 26, 1972.2

At this session, the Soviet Union rejected President Reagan's May 27, 1986, call for the Soviet Union to join the United States in establishing an interim framework of truly mutual restraint pending conclusion of a verifiable agreement on deep and equitable reductions in offensive nuclear arms.3 The Soviet Union was informed that the call remains open.

136. Report to the Conference on Disarmament by the Ad Hoc Group of Scientific Experts To Consider International Cooperative Measures To Detect and Identify Seismic Events: The 1984 Technical Test [Extracts], July 31, 19861

CHAPTER 1

Introduction

The present consensus report, which is the fourth report overall of the Ad Hoc Group of Scientific Experts to Consider International Cooperative Measures to Detect and Identify Seismic Events, contains a detailed presentation of the results and experiences from a large-scale technical test conducted by the Group during 1984. This test, which has been termed the Group of Scientific Experts' Technical Test (GSETT) 1984, has comprised exchange and analysis of seismic Level I data using the Global Telecommunication System of the World Meteorological Organization (WMO) on the regular use basis authorized by the WMO in 1983.

A consensus summary of this report has been submitted to the Conference on Disarmament as document CD/681/Rev.1. The present report has eight chapters, each dealing with different aspects of the Group's work in conducting and evaluating the GSETT. In addition, seven appendices containing detailed and technical material are annexed as an integral part of the report. Consensus was reached on the entire main part of the report, and also on all appendices except 4A, 4B, 5B, 6C, 7A, 7C, 7D, which comprise results of national investigations. These reflect the viewpoints of individual countries on various technical problems and therefore do not require consensus.

A brief overview of the background for the establishment of the Ad Hoc Group is given in the following:

On 22 July 1976, the Conference of the Committee on Disarmament (the CCD) established an Ad Hoc Group of Government-appointed experts to consider and report on international co-operative measures to detect and identify seismic events, so as to assist in the verification of a comprehensive

2 Documents on Disarmament, 1972, pp. 197-201, 868–869. 3 Document 82.

'CD/720, pp. 1-7, 49–52.

test ban.2 The Group submitted its consensus report (CCD/558) in March 1978, describing how seismological science can be applied in a co-operative international effort to achieve this purpose.3 In this sense, the co-operative measures would have three main elements:

-a systematic improvement of the observations reported from a network of more than 50 seismological observatories around the globe

-an international exchange of these data over the Global Telecommunications System of the World Meteorological Organization (WMO/ GTS)

-processing of the data at special International Data Centres for the use of participant States.

The report also considered some steps, such as a comprehensive experimental exercise, which could be taken initially to assist the establishment of such a cooperative international data exchange system.

On 9 May 1978, the CCD decided that the Ad Hoc Group should continue its work by studying the scientific and methodological principles for a possible comprehensive experimental exercise of a global network of the kind described in CCD/558. The Committee on Disarmament (the CD), in its decision of 15 February 1979, maintained the arrangements for the Ad Hoc Group. Subsequently, in July 1979, the Group submitted its second report (CD/43).*

On 7 August 1979, the CD decided (CD/PV.48) that the Ad Hoc Group should pursue its work further, under the following reference:

"1. Recognizing the valuable and important work carried out by the Ad Hoc Group in elaborating instructions and specifications for International Co-operative Measures to Detect and Identify Seismic Events, as presented to the CD in its report of July 1979, the CD decides that the Ad Hoc Group should continue its work on such measures, which might be established in the future for the international exchange of seismological data under a treaty prohibiting nuclear weapon tests covering nuclear explosions for peaceful purposes in a protocol which would be an integral part of the treaty. 2. This work should, inter alia, include:

-further elaboration, with the second report of the Group as a basis, of detailed instructions for an experimental test of the global system for international co-operative measures to detect and identify seismic events;

-further development of the scientific and technical aspects of the global system;

-co-operation in the review and analysis of national investigations into relevant matters such as:

⚫ the conditions for using the WMO Global Telecommunications System for seismic data exchange;

• procedures to obtain desired data at individual stations under a range of conditions;

⚫ the analysis and data handling procedures at the envisaged data centres; and

⚫ methods of rapid exchange of waveform data.

3. The organization and procedures of work of the Group should remain the same as defined by the decision of the CCD on 22 July 1976 and maintained by the Committee on Disarmament by its decision of 15 February 1979. The Ad Hoc Group will hold its first meeting under its new mandate late in January or early in February 1980.

4. The Committee on Disarmament invites WMO to continue its co-operation with the Ad Hoc Group."

On 9 March 1984, the Ad Hoc Group submitted its third report (CD/448)." In this report, the Group expressed the need to conduct further technical tests, in cooperation with the WMO, to establish the operational performance of the WMO/ GTS for seismic data exchange on a global basis. Subsequently, on 13 August 1984, the Group submitted to the CD an overview document (CD/534) containing proposed procedures for one such technical test, named GSETT, to be carried out in 1984. Additional technical information was given in the Group's Conference Room Paper 134/Rev. 1. The results of this test are described in this report.

CHAPTER 2

Organization and Method of Work of the Ad Hoc Group

The Ad Hoc Group is open to all Member States of the Conference on Disarmament as well as to other States Members of the United Nations upon invitation by the CD. Altogether, scientific experts and representatives from 27 Member States of the CD and five other States have participated in the plenary sessions of the Ad Hoc Group under its current mandate, which dates back to 7 August 1979 (CD/PV.48). Names of the participants at different sessions are listed in the Group's Conference Room Papers 132, 140, 144, 150 and 156, and can be obtained from the CD Secretariat.

Upon invitation by the CD, representatives of the World Meteorological Organization (WMO) have attended the Ad Hoc Group's sessions, and their valuable advice and assistance with regard to transmission of seismic data on the Global Telecommunication System (GTS) of the WMO has been essential in ensuring the success of the GSETT.

Dr. Ola Dahlman of Sweden has served as Chairman of the Ad Hoc Group. Dr. Frode Ringdal of Norway has served as the Group's Scientific Secretary. Mr. Michael Cassandra, United Nations Department for Disarmament Affairs, has

5 CD/46.

"Ibid., 1984, pp. 146–156.