Surface Nuclear Magnetic Resonance at Blair Wallis, Wyoming

All of the surface NMR soundings in this study used a 46 m diameter circle-eight loop, a 20 ms pulse, and two noise loops of approximately the same shape, size, and orientation. Using this configuration, we were able to achieve high-quality signal and observe exponential decay over a swath of pulse moments and we successfully removed 60 Hz harmonics caused by anthropogenic sources. Loop orientation was selected to minimize topography change over the loop. Even with noise cancellation, the signal was small, and we stacked each pulse moment between 16 and 22 times. We inverted the surface NMR data with a mono-exponential decay using MRSMatlab and a QT inversion using a magnetic inclination of 67.4°.

More information: Flinchum, B., Holbrook, W., Parsekian, A., Carr, B. (2019). Characterizing the Critical Zone Using Borehole and Surface Nuclear Magnetic Resonance Vadose Zone Journal 18(1), 1-18. https://dx.doi.org/10.2136/vzj2018.12.0209