https://declassified.library.utoronto.ca/files/original/c1a9c5161f19ec31b2cd35ffe91c484f.pdf a070f4323ea1402df267046dfff0b059 PDF Text Text Document disclosed under Document divulguey&n vertu ( 0.0 T if?- MIN'STEH r -{ViVS I ° >ET*\ 1* '•*'- • •» N •• f •• 1'^.CAi. SjRVEY'i $fi»V; APft 1 8 MINISTRE "es ^ SCS ET OES RELEvES TECHNIQUES Ottawa 3 , 0 n t a p £ 5 , A p r i l 7 , 196,6^ A £6-8-4- 3. j JB 3r REGISTRY K cqitFTDonrnr 2=k>7-//- 7 :jH-r/-y'' -^ Under-Secretary of State for External Affairs, East Block, Parliament Buildings, Ottawa, Ontario ATTENTION: Mr. D. M. Copnfett, Chief of Disarmament Division Dear Mr. Cornett: I understand that the questions posed in your memorandum of March 22nd re Comprehensive Test Ban Treaty have been discussed at a meeting, April 5th, between officers of the Disarmament Division of the Dept. of External Affairs, and Dr. J. Hodgson, Dr. K. Whitham and Mr. E.B. Manchee representing this Department. Our technical competence can only be addressed to the first of the two general problems raised, namely the problem of detecting and identifying underground tests. Furthermore, since there has been no research or evaluation programme in this Department in this enormously complicated field, the opinions of our officers can only be based on the scientific information available to them and must obviously often be very general, rather than specific as you would probably prefer. If one considers the enormous effort in the U.S.A. and the very large U.K. programme, the uncertainties- in the answers of our technical people should become understandable, even if regrettable. i 4 i With these reservations, partial answers discussed at the meeting of April 5 are repeated below to questions 1, 2 and 4 to 11. Question 3 and the later series of questions are military matters, outside the competence of this Department. (1) It is uncertain what the threshold is above which we can now identify all events in the U.S.S.R. However, U.K. work suggests that between 80% and 85% of all events in the U.S.S.R. with mif/ or greater could be identified with a concentrated effort using present facilities 4 2 3 i 000035 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'informath - 2 - CONFIDENTIAL in a number of countries. It appears possible that with a modest effort, identification could be made practically unambiguously at m5 or greater. Factors of 10 in capital cost, computing equipment and manpower are crudely equivalent to \ magnitude, i.e. an increase in the total western world effort by ten times might push the same identification probability down to m3s, although this is not certain. (2) Probably yes if decoupling is possible, and very small nuclear weapons are used. Directly relevant Canadian experience is that the detection of well coupled explosion of 2 tons beyond 2,000 to 3,000 kilometres is difficult. A small explosion, with considerable decoupling in the centre of the U.S.S.R. would be difficult to detect, and even more difficult to identify. (4) We believe this question is unanswerable. Once signal diagnostic features have been assessed through an operating and research program, statements of probability for certain stations and certain proving grounds are possible. One-hundred per cent probability based on one station appears very unlikely. (5) I quote from A.K. Longair, D.R.B., his understanding which is also that of the Observatories Branch "the pessimists in the U.S.A. say that of the possible 250 events annually in the U.S.S.R., the use of LASA will reduce the number of unidentified events only from 80 to 55". This is a percentage change from 68% identification capability to 78% identification capability, or an improvement of 10 parts in 68 or 15%. (6) With the membership presently contemplated, and.assuming operational status of the different national elements, U.K. figures suggest that between 5 and 20% of seismic events, m4 or greater, would remain doubtful. There is room for considerable uncertainty here, and only a Canadian programme would provide an independent answer. The U.K. estimate is that the 'Yellowknife only' identification capability on U.S.S.R. events is about 50% of those detected. (7) Yes, if cost were no object. (8) The concept, as we see it, calls for cooperation and interchange of data between the different national elements using presently existing facilities only, at least initially. Ocean-flowseismographs have been developed, built and tested in the U.S.A. 000036 �Document disclosed under the Access to Information Act Document divulgue en vertu de la Loi sur I'acces a I'information .a - 3- CONFIDENTIAL (9) This is a technical matter. The theory is that modest capital expenditures could improve the British-type arrays by substituting a small cluster for each individual element. For example, Yellowknife array detectability with no increase in computing costs might be improved by 0.35 magnitude. The extra expenditure would certainly be about 1% only of LASA costs, but the improvement could not exceed the figure quoted above and might be far less, without vast and expensive changes in data processing. Our seismologists support the more modest network concept of the U.K. for monitoring any test-ban with a small number of widely distributed LASA's acting essentially as sentinels for low magnitude events, and a more widely distributed and larger number of medium aperture arrays, improved small aperture arrays and ocean bottom or borehole seismometers in critical areas. If the total amount of available money is specified and a magnitude criterion given, it would be possible to conduct cost-effectiveness studies of different proposals. One is talking about several hundred million dollars in capital expenses for realistic networks. (10) Our seismologists can see no reason to dispute the extrapolation and educated guesses involved in (C) p. 50 of the UKAEA paper. With no detection capability at these levels other than LASA, no scientific estimates can be made. We believe that classified probability studies have been made by the D.N.D. which are relevant to the last part of the question. (11) Any judgements at m7 with several reports would be far more categorical than at m4 with one report. Please note the answer to (4) above. Finally we have no technical expertise in the field of 'on-site' inspections, and can give no expert opinion on its value. i ! I' \ Sincerely, M. Harrison, Assistant Deputy-Minister (Research). •% J I * " 000037 � Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context CDBM00010 Title A name given to the resource Letter to Under Secretary of State Date A point or period of time associated with an event in the lifecycle of the resource 4/7/1966 Source A related resource from which the described resource is derived RG25-A-3-c, file 27-11-7, "DEFENCE - CONVENTIONAL AND NUCLEAR ARMAMENTS - ANTI - BALLISTIC MISSILES (ABM) = DEFENSE - ARMEMENTS DE TYPE CLASSIQUE ET NUCLEAIRE - ENGINS ANTIMISSILES (ABM)," vol. 10357, part 1, Library and Archives Canada, (LAC). Creator An entity primarily responsible for making the resource External Affairs Rights Information about rights held in and over the resource Canadian Crown Subject The topic of the resource Anti-ballistic missiles Description An account of the resource Comprehensive Test Ban Treaty Publisher An entity responsible for making the resource available Canada Declassified Type The nature or genre of the resource Text Format The file format, physical medium, or dimensions of the resource PDF Language A language of the resource en