In-situ gravity measurements using a vibrating beam MEMS accelerometer designed for surface microgravimetry.

Abstract

<p>A differential vibrating beam MEMS gravimeter has been produced and used for the first time in a prototype system to measure and map a gravity anomaly. The Allan deviation for the system is 10 μGal for an integration time of 1000 s. The specification of the MEMS gravimeter is consistent with earlier prototypes [1, 2] reported on in previous years, where we have shown instances of tidal tracking and seismic measurements.</p><p>Here, we present results of our first mapping of a gravity anomaly with the SMG-Grav10 prototype system. The measurements were taken at the new National Buried Infrastructure Facility (NBIF), sited at the University of Birmingham; where a 2 m diameter cylindrical plastic pipe has been buried under sand at a depth of 0.3 m, producing a modelled gravity anomaly of ~40 µGal. Gravity data was acquired at a number of stations situated along a survey line on the surface above the NBIF tunnel. The vibrating beam MEMS gravimeter has been able to record the resulting gravity anomaly and recreate the modelled relative gravity values. The average error reported across all measurement stations is 10 µGal, with the smallest measurement error of 5 µGal. These results are benchmarked relative to a commercially available reference gravimeter (Scintrex CG-6) employed to map the same anomaly.</p><p>[1] Topham, A. <em>et al</em>., Use of a vibrating beam MEMS accelerometer for surface microgravimetry, EGU 2021.</p><p>[2] Mustafazade, A., Pandit, M., Zhao, C. <em>et al</em>. A vibrating beam MEMS accelerometer for gravity and seismic measurements. Sci Rep 10, 10415 (2020).</p>