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Comparing Observed and Modelled Station Terms from the Source Physics Experiments Phase 2 (Dry Alluvium Geology) Explosions

Description: 

Since 2011, a series of chemical explosions with a range of different depths and explosive yields have been detonated at two sites on the Nevada National Security Site (NNSS) to help further understanding of the seismic waves generated by underground explosions. In this study, P-wave amplitudes recorded from explosions in the second phase of the Source Physics Experiments (SPE) explosions at stations ranging from 2 km to around 36 km distance have been analysed and compared with model predictions. The model seismograms were computed using a visco-elastic wave propagation code and a high resolution 3D Earth model of the NNSS. For comparison model seismograms are scaled using two explosion source models, the Mueller-Murphy model and Denny and Johnson model. In order to assess how effective the 3D Earth model was at modelling path effects between the location of the explosions and the stations, a two-step inversion was carried out to estimate station and distance terms for the stations used in this study for both the observed data and model data scaled using both source models. Although there are some differences between the observed and modelled station terms, in general there is reasonable agreement and one of the main features in the observed data, negative station terms for stations at around 10 km distance from the location of the stations, is replicated in the model data. Distance terms which predict the fall-off of amplitude with distance were also estimated for the observed and model data and are found to be in good agreement.

Session: Advancements in Forensic Seismology and Explosion Monitoring [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Ross

Student Presenter: No

Invited Presentation: 

Authors