HC Deb 12 January 1987 vol 108 c8W
Mr. Ashdown

asked the Secretary of State for Foreign and Commonwealth Affairs what responses he has had to the paper, "Seismic Monitoring for a Comprehensive Nuclear Test Ban", submitted to the conference on disarmament in July 1985; and if he will make responses available in the Library.

Mr. Renton

At the conference on disarmament in Geneva there has been only one technical paper (CD712) directly commenting on the United Kingdom's paper. As with all CD papers, a copy is available in the Library of the House.

There have been a number of comments in the United Kingdom on CD610. Most recently, "Modern Geology" published a number of articles on it; a copy is in the Library of the House. These articles were noted in the national press at the time, including a commentary in the Guardian of 20 November. This, like the articles, was misleading in several respects.

The "dramatic new evidence" presented under the title of "Earthquake in Kazakhstan" is neither new nor dramatic. The seismograms illustrated are from seismic disturbances that took place seven and a half years ago, on 14 September 1979. Contrary to claims in the articles, the seismograms in question were not obtained by high frequency means. The signals were recorded and detected automatically using the standard processing system at the NORSAR array in Norway. NORESS, the high frequency array, had not been installed at that time, and data from high frequency systems are not available for these seismic disturbances. In any case, there is some evidence that the high frequency content of signals caused by small earthquakes is rather like that from similarly sized nuclear explosions in regions of similar geology.

The earthquake occurred not in Kazakhstan as stated, but in the Kamchatka region, some 5,800 km distant. Geological differences and the size of the seismic disturbances rather than high frequency detection techniques, are responsible for differences in the frequency content of the seismogram. As stated in the articles, a spike-like feature identified in the lower trace originated from Kazakhstan. However we cannot be certain that it was caused by a nuclear explosion; the USSR does not, as a matter of policy, announce such tests. It would hardly be surprising if the signals from two widely separated regions differ in their characteristics.

In response to technical comments on the United Kingdom paper, the Government prepared in mid-1986 a response to press and "Modern Geology" reports. I am placing a copy of this in the Library of the House. It deals with three main areas:

  1. (a) claims for the effectiveness of high frequency monitoring;
  2. (b) claims that the Mb:MS criterion provides reliable and effective means of distinguishing between nuclear explosions and natural seismic events;
  3. (c) claims that unannounced nuclear explosions in the US had been detected in Sweden, when in actual fact the explosions in question were detected and reported in the US and the relevant information then passed and republished by interested circles in Sweden.