MEMS Gravimeters as a New Tool for Gravity Imaging

A microelectromechanical system (MEMS) gravimeter has been manufactured with a sensitivity of 40 parts per billion in an integration time of one second. This sensor has been used to measure the Earth tides; the elastic deformation of the globe due to tidal forces. No such measurement has been demonstrated before now with a MEMS gravimeter. Since this measurement, the gravimeter has been miniaturised and tested in the field. Measurements of the free-air and Bouguer effects have been demonstrated by monitoring the change in gravitational acceleration measured whilst going up and down a lift shaft of 20.7 m, and up and down a local hill of 275 m. These tests demonstrate that the device has the potential to be a useful field-portable instrument. The development of an even smaller device are underway, with a total package size similar to that of a smart phone.