Measurement of the Earth tides with a MEMS gravimeter

Middlemiss, R. P. , Samarelli, A., Paul, D. J. , Hough, J. , Rowan, S. and Hammond, G. D. (2016) Measurement of the Earth tides with a MEMS gravimeter. Nature, 531(7596), pp. 614-617. (doi: 10.1038/nature17397) (PMID:27029276)

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The ability to measure tiny variations in the local gravitational acceleration allows, besides other applications, the detection of hidden hydrocarbon reserves, magma build-up before volcanic eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required for such applications (tens of microgal per hertz1/2): free-fall gravimeters1, spring-based gravimeters1, 3, superconducting gravimeters4, and atom interferometers5. All of these devices can observe the Earth tides6: the elastic deformation of the Earth’s crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of high cost (more than 100,000 US dollars) and high mass (more than 8 kilograms). Here we present a microelectromechanical system (MEMS) device with a sensitivity of 40 microgal per hertz1/2 only a few cubic centimetres in size. We use it to measure the Earth tides, revealing the long-term stability of our instrument compared to any other MEMS device. MEMS accelerometers—found in most smart phones7—can be mass-produced remarkably cheaply, but none are stable enough to be called a gravimeter. Our device has thus made the transition from accelerometer to gravimeter. The small size and low cost of this MEMS gravimeter suggests many applications in gravity mapping. For example, it could be mounted on a drone instead of low-flying aircraft for distributed land surveying and exploration, deployed to monitor volcanoes, or built into multi-pixel density-contrast imaging arrays.

Item Type:Articles (Letter)
Glasgow Author(s) Enlighten ID:Hammond, Professor Giles and Middlemiss, Dr Richard and Rowan, Professor Sheila and Samarelli, Mr Antonio and Hough, Professor James and Paul, Professor Douglas
Authors: Middlemiss, R. P., Samarelli, A., Paul, D. J., Hough, J., Rowan, S., and Hammond, G. D.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > School of Engineering
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
College of Science and Engineering > School of Physics and Astronomy
Journal Name:Nature
Publisher:Nature Publishing Group
ISSN (Online):1476-4687
Copyright Holders:Copyright © 2016 Nature Publications
First Published:First published in Nature 531(7596):614-617
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
Related URLs:
Data DOI:10.5525/gla.researchdata.213

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
662111Monolithic Silicon Photonics Interferometer for Ultra-sensitive MEMS SensorsGiles HammondScience & Technologies Facilities Council (STFC)ST/M000427/1S&E P&A - PHYSICS & ASTRONOMY