Time-Variable Moment Tensor Inversion of Seismic Data Collected at Blue Canyon Dome

ABSTRACT We invert seismic data collected at Blue Canyon Dome, west of Socorro, New Mexico, to obtain a time-domain representation of the evolution of eight seismic sources from Blue Canyon Dome Phase II. This experiment consisted of eight chemical explosions (or shots), three with dry emplacements and five with wet emplacements. The three dry shots are co-located at depth with three of the wet shots. Seismic and distributed acoustic sensing data recorded at the site both show a polarity reversal in the dry shot data when compared with the wet shot data located at the same depth. This implies that there is a physical explanation for this polarity reversal because it is captured across two different data modalities. In addition, the moment functions (MFs) recovered from our inversions show source mechanisms consistent with the polarities present in the observed data. Inversion of 24 three-component seismic stations filtered in four frequency bands, 5–10, 9–15, 5–15, and 8–20 Hz, as well as inversions run using data from three different station geometries, resulted in an early-time net negative volumetric change in the MFs from the dry shots and a net positive volumetric change for the wet shots. The water in the near-source region, in which the wet shots were emplaced, appears to have a significant impact on the recovered yield for these shots.