Earthquake or Explosion - Computers in Seismology applied to Test-Ban Verification

Speakers: Alan Douglas
Date: 17th March 2011
Time: 14.30 Room open in advance (from 14.00) – meet up with society members.

Fellows Library of the Science Museum, Exhibition Road, London, SW7 2DD

About the seminar

In this talk the history of nuclear test ban negotiations is described and how the problems of verifying compliance with a CTBT were overcome, in particular how computers were used to process and analyse the seismic waves generated by earthquakes and explosions.

In 1963 the Partial Test Ban Treaty (PTBT) banned nuclear explosions everywhere except underground. To convert the PTBT into a Comprehensive Nuclear Test Ban Treaty (CTBT) required some way of detecting and identifying underground tests. The only way that underground tests can be detected is by the seismic waves generated. The question for seismologists was: is it possible to detect and identify low-yield (1kt?) tests? One kilotonne gives an extremely small ground displacement of around 1/1000,000,000m at long range.

A new branch of seismology - forensic seismology -came into existence which it was hoped would help convict a state that carries out a clandestine test and conversely acquit a state falsely accused of testing. The detection and recognition of underground explosions proved to be a very difficult task, so that it was only in September 1996 that forensic seismology had advanced far enough for a CTBT to be finally negotiated.

Some of the most important advances in forensic seismology were made by the Atomic Weapons Establishment.

About the speaker

Alan Douglas worked for over 35 years in the Seismology Group of the Atomic Weapons Establishment, Aldermaston. He continues to act as a consultant to the Group. He has a B.Sc. in Geology from Leeds University and an M.Sc. in Geophysics from the University of London. For many years he was a Visiting Professor at The University of Reading and is currently a Visiting Professor at University College, London. He is an Author of over 100 research papers and reports on seismology applied to the verification of test ban treaties. In 2005 he received the Award for Service to Geophysics from the Royal Astronomical Society


See the Wikipedia entry with information about the Comprehensive Nuclear-Test-Ban Treaty (CTBT) .


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