Foreign Relations of the United States, 1958–1960, Volume III, National Security Policy; Arms Control and Disarmament, Microfiche Supplement

553. Paper¹

March 28, 1960

The Need for Nuclear Detonations in a Seismic Research Program

While it appears that educated guesses, based on the best relevant theoretical considerations, indicate that the difference between HE and nuclear explosions in terms of amplitude of seismic signal might be within the range of factors of 2–5, it is believed that a program of nuclear detonations is necessary, for the following reasons:

(1) At the present time there is no experimental data to connect the seismic signals from deep, contained HE and nuclear detonations.

(2) There is no generally accepted theory connecting seismic signals with the details of the source. Speculations as to the behavior of nuclear detonations, unsupported by actual evidence, should be tested. Data is needed on which to base conclusions, or better inferences, as to: spectrum of frequencies of shocks generated, effect of environment (gas & water content, etc.), and the state and behavior of the vaporized material.

(3) The effect of different media must be further known. To date deep underground nuclear detonations have only been conducted in Nevada tuff. Even with contained experiments with H.E. in this medium, extrapolation of effects to other media could be very misleading.

(4) The effect of different crustal environments between source and receiver can be important in determining the characteristics of signals received by a seismic station. Again, nuclear detonations are needed in other locations, as well as in other media, to obtain definite information on this.

(5) For proper evaluation of the capabilities of Geneva stations it is essential to have data at larger ranges. There are yield limitations on the use of HE, in that the volume of HE alone for 5 KT requires a spherical cavity of 60–75 feet diameter. Larger yields than 5 KT are highly desirable for the experimental program.

(6) There have been no nuclear “big hole” decoupled shots. The differences between HE and nuclear detonations should be further examined experimentally since there is expected to be a difference in the shock phenomenology occurring.

(7) It is important to keep in mind that if there is a now unknown characteristic of the seismic wave which would prove to be more useful for detection and identification than any now known, it can be discovered only by experiments with nuclear sources.

1. Source: “The Need for Nuclear Detonations in a Seismic Research Program.” Confidential. 1 p. Eisenhower Library, Whitman File, Miscellaneous Series, Macmillan, Vol. II.