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Time-Varying Source Processes of the Source Physics Experiment Explosions

Description: 

The Source Physics Experiment (SPE) was a series of planned chemical explosions at the Nevada National Security Site (NNSS). SPE Phase-I (2011-2016) provided a wealth of dense, local- to regional-distance observations suitable for characterizing shallow chemical explosions located within the same borehole. We investigate the time-dependent source processes of each chemical explosion using frequency-domain moment tensor inversion and relative source time function (RSTF) estimation using data from five linear seismometer profiles located between 100 and 2000 meters of the shot location. Our results from the frequency-domain moment tensor inversion suggest that we can determine the time-history of each source. However, the application of this inversion approach to the SPE tests is challenged by the limited frequency response of the seismometers and knowledge of fine scale heterogeneous Earth structure. We attempt to confront these limitations post-inversion by reconstructing relative source time functions (RSTF) to improve the resolution of time-dependent source processes. The RSTF estimates provide exceptional resolution to each explosion’s time-history. Preliminary modeling efforts suggest these measurements may be useful for precise characterization of explosion processes and spallation. Using both moment tensor inversion and the relative source time functions allows us to expand our understanding of the SPE Phase-I explosion series. Application of these techniques contributes to our understanding of explosion source physics and facilitates future applications to additional seismic source experiments and phenomenology.

Session: Exploiting Explosion Sources: Advancements in Seismic Source Physics [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: James E. Pippin

Student Presenter: Yes

Invited Presentation: 

Authors