Empirical and Theoretical Seismic Energy Partitioning from Explosions Under Different Confinement and Media Conditions

摘要

Some of the data-analysis results from the 2003 Arizona Source Phenomenology Experiments (SPE) were unexpected-explosions in slow-velocity limestone appear to be mainly isotropic under most emplacement conditions, while explosions in higher-velocity granite porphyry are marked by interesting source anisotropy. Even though the emplacement media were different, we did not expect to observe such prominent differences in the explosion phenomenology. While the SPE project was successfully completed, important questions remain regarding the fundamental physical mechanisms behind these differences, which could have important implications on explosion-generated S-wave models. To improve our understanding of the physics behind the explosive-source phenomena, we are comparing the SPE data to that of other explosion experiments, including the Non-Proliferation Experiment (NPE). We are attempting to (1) develop a physical interpretation of the different SPE sources using comparative moment tensors analyses; (2) quantify the effects of spall, compensated linear vector dipole (CLVD), and other secondary sources; (3) characterize near-source, local, and regional S-wave phases, including prominent SH waves; (4) conduct moment tensor inversions of NPE explosions, including an overburied 177-kg calibration explosion, for comparison to the SPE explosions; and (5) examine the variability of regional phase partitioning from single-fired and production mining explosions in order to assess the transportability of regional discriminants. We have just started a two-year, multi-phase physical basis investigation aimed at developing a new explosion source model explaining the differences between the isotropic explosions in highly fractured limestone and anisotropic explosions in granite porphyry.