Münster 2017 – scientific programme

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AGA: Arbeitsgruppe Physik und Abrüstung

AGA 7: Seismic and Acoustic Verification

AGA 7.1: Talk

Friday, March 31, 2017, 10:30–11:00, S Aula

Safeguards for Final Repositories: Using Analytical Seismic Signals — •Jürgen Altmann — Experimentelle Physik III, Technische Universität Dortmund, 44221 Dortmund

To analyse the potential of seismic monitoring for detecting undeclared activities at an underground final repository for nuclear waste, seismic propagation had been modelled numerically at a salt dome with a complex underground structure. The model had included frequency-dependent attenuation but the time and space resolutions were limited; signal frequencies were below a few hundred Hz.

The results showed that the amplitude changes on transmission through media boundaries were relatively modest. Thus a homogeneous-medium model without any boundaries was used where the seismic wave field can be described by analytic formulae, and the signal frequencies are not limited. The analytical amplitudes fit very well to the numerical ones; with signal frequencies up to a few hundred Hz, in salt and other consolidated sediments the numerical amplitudes start to get lower at around 1 km, probably because they include attenuation.

It seems that the analytic treatment by a homogeneous medium can give useful results for the estimation of signal strengths at relevant distances, important for a first estimate of the capabilities of a potential monitoring system. For more realistic results frequency-dependent attenuation needs to be included.