Relative Source Time Functions, Spectral Ratios, and Near‐Source Spallation in the Source Physics Experiment Phase I Chemical Explosions

Abstract

The Source Physics Experiment (SPE) Phase I was composed of six chemical explosions at the Nevada National Security Sites (NNSS) between 2011 and 2016. The experiment provided a robust set 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 Relative Source Time Function (RSTF) estimation, derived from five linear seismometer profiles located between 100 and 2000 m of the shot location. The RSTF estimate provide a detailed characterization of each chemical explosion's time‐history. Subsequent modeling efforts suggest these measurements may be useful for precise characterization of explosion processes and spallation. RSTF estimation allows us to expand our understanding of the SPE Phase I chemical explosion series. Application of these techniques contributes to our understanding of explosion source physics and facilitates future applications to additional seismic source experiments and characterization of explosion phenomenology.