Heidelberg 1999 – scientific programme

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AKA: Arbeitskreis Physik und Abrüstung

AKA III: HV III

AKA III.1: Invited Talk

Thursday, March 18, 1999, 11:30–12:30, CH3

The Nuclear Tests in India and Pakistan of May, 1998: Possibilities and Limitations of Seismic Verification — •Jörg Schlittenhardt — Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover

In May 1998 both India and Pakistan conducted two series of underground nuclear explosions. Shortly after the tests, detailed information about the test programme, including the number and type of the explosions and their TNT equivalent, was released by the Indian and Pakistani governments. The fact that not all of the announced explosions were detected by the International Monitoring System (IMS) and the discrepancies that arose between the subsequently calculated seismic yield and the No-dqannouncedNo-dq yield triggered several critical articles in a number of reputed science journals questioning the reliability of seismic verification and of the IMS, which is being set up to monitor compliance with the CTBT (Comprehensive Test Ban Treaty). In the public discussion a number of questions were addressed to the German NDC (National Data Centre): 1) Can individual explosions of these two series be distinguished by seismic means? 2) Why was the second Indian test not detected? 3) How strong was the yield of the explosions? 4) Can the explosions of these tests be distinguished from earthquakes? 5) What is the reason for the difference between the calculated seismic yield and the official yield of the first Indian test?

In this discussion the determination of seismic yield turned out to be an issue of central importance. The seismic yields determined for these tests are also important for determining how weak an explosion can be and still be detected and identified by the IMS. The above issues will be discussed in the light of the current state of the IMS deployment and the methodology for estimating yield that has been developed and successfully applied at the German NDC over the years to a number of nuclear test sites around the world.