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Evaluation and correction of timing inconsistencies from the Thor 1 and Thor 2 experiments at the Nevada National Security Site

Phillips-Alonge, Kristin E.; Abbott, Robert A.; O'Rourke, William T.

Active source seismic data was collected at the Nevada National Security Site using the Seismic Hammer(TM) (SH), under contract from HK Exploration. The SH generates a seismic pulse by dropping a 13 metric ton mass from a height of 1.5 m. Post-survey evaluation of collected data revealed inconsistencies in shot trigger time that required additional analysis and correction using cross-correlation and/or time shifts derived from manual picks of trigger times. While the primary analysis for which this data set was collected is independent of the knowledge of shot trigger time, other processing methods require highly precise knowledge of the trigger time. In order to make the Thor data set more usable to the larger community, additional work was undertaken. Results using the preferred method of cross-correlation were found to be satisfactory. An improved timing fiducial approach is required to reduce timing errors.