Seismic verification of a comprehensive test ban

The capabilities of in-country seismic monitoring systems for verifying the absence of underground nuclear explosions are compared against challenges posed by possible clandestine testing schemes. Although analysis indicate that extensive networks of in-country seismic arrays are needed to verify a Comprehensive Test Ban Treaty, such networks cannot ensure that all underground nuclear explosions will be identified. Political and military judgments will determine the level of risk acceptable to each nation.     

A comprehensive ban on nuclear testing

Our foregoing analysis of the role of a comprehensive test ban leads us to the following conclusions. 1) A CTB by itself will have little direct effect on the arms race between the superpowers. It would not hinder their nuclear arms production and deployment nor would it necessarily present a significant obstacle to the development of new nuclear weapons systems, despite limiting the development of new nuclear warhead designs. It can hardly make a dent in the destructive capability of the superpowers or in their ability to step up the pace of the arms race. 2) The chief merits of a CTB reside in the political sphere. It would help promote detente and could help to escalate interest in arms control agreements of broader scope. But in neither of these effects would it be as significant as a successful SALT (strategic arms limitation talks) agreement. The CTB also lingers as a piece of unfinished business since the signing of the LTB in 1963. The question can be and has been raised, "If the superpowers are serious about arms control, why have they not accepted the CTB, which is simple in concept and in form and is also free of serious military risks?" Such doubts about the sincerity of the superpowers' willingness to limit their own arms development will persist as long as there is no CTB. Substantial agreement at SALT would lessen some of this effect too, but would not eliminate it completely. 3) Recent progress in seismic identification has been impressive, and other means of obtaining technical intelligence about nuclear testing have probably also improved greatly. In addition, research on the technical means of on-site inspection has demonstrated its limited effectiveness. Therefore, the role of on-site inspections as an added deterrent to cheating on a CTB has diminished substantially. This is not to say that detection and identification of all nuclear tests is possible now, or ever, but only that on-site inspection would add very little to the other technical means now available for verification. 4) It will become increasingly difficult in the United States to oppose the CTB on the basis of risks that accompany possible Soviet evasion of a treaty that does not include the right of onsite inspection. The opposition to a CTB is now likely to shift to the more direct argument that nuclear testing is important to keep pace with continuing worldwide technical and military developments. The justification for U.S. testing is only in part because of advances in Soviet nuclear technology per se. Those opposing a CTB may argue that it makes little sense, and may even be courting danger, to freeze nuclear technology alone and that banning nuclear tests should await an agreement that copes with all military research and development and all qualitative improvements in weapons systems. This directly confronts the argument that the unique virtue of a CTB is that it provides a simple and feasible first step in the very complicated problems of controlling military technology. 5) The mutual deterrence of the superpowers will not be compromised if a CTB agreement is reached and one side or the other clandestinely violates such an agreement. The state of nuclear technology in both countries is mature, and the destructive capability of their nuclear arsenals can be easily maintained. Whatever small improvements can come as a consequence of clandestine testing would hardly affect the strategic balance. 6) It seems unlikely that China and France will agree to stop testing in the near future. These countries refused to join the nonproliferation treaty, which did not affect their nuclear programs, and it is doubtful that, proceeding from military considerations alone, they would join a CTB. Their nuclear programs are still not mature, and a CTB would freeze their positions of inferiority with respect to the superpowers. There may, however, be wider political and security arrangements to induce them to participate. Cessation of tests by the other nuclear powers might serve as an inducement to China and France to refrain from testing. 7) The key near-nuclear powers, such as Japan, India, and Israel, are much more concerned with the military activities of their neighbors than they are with those of the superpowers. The modest nuclear restraints that a CTB imposes on the superpowers are hardly likely to have a direct impact on the approach of these countries to their own security. However, for these critical near-nuclear countries a CTB may be much more acceptable than the nonproliferation treaty. A CTB would not prohibit the production of fissionable material, the development of nuclear weapons technology short of testing, nor the stockpiling of untested nuclear weapons, and is therefore less restrictive. Consequently, these powers may be willing to ratify a CTB, but not the nonproliferation treaty. On the other hand, the CTB may provide them with a ready excuse for not succumbing to the pressure to ratify the nonproliferation treaty, if indeed they need excuses or would bow to such pressure. 8) A CTB is of very little added, direct significance to other nonnuclear powers who have already ratified or are about to ratify the nonproliferation treaty. It may only lessen their pique about the treaty's being highly discriminatory-the treaty imposes no restraints on the nuclear weapons programs of the nuclear powers, while the CTB restricts all parties to the agreement. 9) Peaceful nuclear explosions do not now show great promise and significance for economic development. What can be done with peaceful explosions can often be done by other means, although possibly at a slightly higher cost. On the other hand, making allowance for peaceful explosions greatly complicates a CTB. A useful approach to the problem of banning military tests but not foregoing indefinitely the use of peaceful explosions might, therefore, be to ban all nuclear explosions for a period of several years and to stipulate in the agreement that in that time there would be negotiations on how peaceful explosions may be controlled in a way that would not jeopardize the CTB.