Seismic Signals from Sandia National Laboratory’s Z Machine and Time-Dependent Velocities in the Albuquerque Basin

Session: Back to the Future: Innovative New Research with Legacy Seismic Data
Type: Oral
Date: 4/28/2020
Time: 09:30 AM
Room: 230 + 235
Description: 

Sandia National Laboratories Z Machine is an ongoing high-energy physics experiment that can shock materials to achieve high temperatures and pressures that may exist within stars or large planetary interiors. The Z Machine has been in operation since the mid-1990s. When these high energy pulses or ‘shots’ are released, they produce ~4-16 Hz ground velocity waveforms that are detectable 12 kilometers away at the Albuquerque Seismology Laboratory’s ANMO borehole seismometer. The waveforms of the shots are highly correlated and can be found in the seismological record going back to 1996. Based on 74 known shots from 2018 three-component template correlation was used to detect 2168 Z Machine shots in the ANMO data record. This highly repetitive source of high frequency seismic energy is well-suited to application of coda wave interferometry to investigate time-dependent velocity of the upper crust in the Albuquerque Basin. We propose that small fractional changes in velocity (dv/v) between the Z Machine and ANMO are controlled by hydrologic parameters in the Albuquerque Basin. Groundwater level measurements from the Montessa Site Well on Kirtland Airforce Base are collected daily going back to 1992. Coda wave interferometry results shows that dv/v is correlated with the depth to water table from the Montessa Site Well. Ongoing research will further investigate temporal variations in the amplitude of seismic signals from the Z Machine to evaluate the relative contributions from facility upgrades and temporally varying properties of the upper crust.

Presenting Author: Ryan K. Stairs

Authors