The subject of this NATO Advanced Study Institute was seismic monitoring
under a nuclear test ban - an application of scienti- fic knowledge and
modern technology for a political purpose. The international political
objective of a comprehensive nuclear test ban provided in turn the
motivation for our technical and scientific discussions. In order to
obtain a historical perspec- tive on the progress of the work towards a
comprehensive test-ban treaty (CTB), it is necessary to go back to 1958,
when a confer- ence of scientific experts in Geneva made the first steps
toward an international seismic monitoring system. However, agreement on
actual capabilities of a monitoring system for verifying compliance with
such a treaty was not achieved, and thus the conference did not lead to
immediate political results. After the Partial Test Ban Treaty of 1963,
which banned nuclear explosions in the atmosphere, outer space and under
the seas, renewed interest in the seismological verification of a CTB
took place. A number of countries initiated large-scale research efforts
toward detecting and identifying underground nuclear explosions, and it
was in this context that the large- aperture seismic arrays NORSAR and
LASA were established. This type of development resulted in excellent
seismic data in digital form and was thus of great irnprotance to the
seismological com- munity.