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Mr Neil Wilkins

Optimising array methodologies for forensic, industrial and global seismology

Forensic seismology is the application of seismological techniques to the analysis and identification of events that are suspected of being related to illegal activity, predominately the testing of nuclear warheads. My research project is a NERC CASE studentship in collaboration with AWE Blacknest, one of the organisations responsible for the enforcement of the Comprehensive Nuclear Test Ban Treaty (CTBT).

Monitoring the seismic waves originating from suspicious events is one of the most important parts of verifying whether or not the event was the result of a nuclear explosion. However, discerning such events from natural and non-nuclear sources of seismicity requires detailed measurement of the seismic waveform. It is thus necessary to achieve a high signal-to-noise ratio (SNR) in the seismic data that is to be analysed.

Over half of the Primary seismic stations of the International Monitoring System (IMS) of the CTBT organisation (CTBTO) are small-aperture seismic arrays. The SNR of the data from these arrays can be improved by stacking the seismograms from each element in the array. The first part of my project focussed on developing stacking techniques to achieve improved SNRs on such small-aperture seismic arrays.

I have also developed code to calculate corrections to the observed slowness and azimuth of the seismic wavefield arriving at an array. Applying these corrections to IMS Primary seismic arrays improves the SNR of the stack. I am invesigating how this SNR improvement affects both the detection of suspicious events, and the calculation of seismic discriminants, in particular for the sequence of nuclear tests conducted by North Korea.

Research keywords

  • Seismology
  • forensic seismology
  • global seismology
  • seismic array processing