A vibrating beam MEMS accelerometer for gravity and seismic measurements

Abstract

This paper introduces a differential vibrating beam MEMS accelerometer demonstrating excellent long-term stability for applications in gravimetry and seismology. The MEMS gravimeter module demonstrates an output Allan deviation of 9 μGal for a 1000 s integration time, a noise floor of 100 μGal/√Hz, and measurement over the full ±1 g dynamic range (1 g = 9.81 ms−2). The sensitivity of the device is demonstrated through the tracking of Earth tides and recording of ground motion corresponding to a number of teleseismic events over several months. These results demonstrate that vibrating beam MEMS accelerometers can be employed for measurements requiring high levels of stability and resolution with wider implications for precision measurement employing other resonant-output MEMS devices such as gyroscopes and magnetometers.

Sub-Deg-per-Hour Edge-Anchored Bulk Acoustic Wave Micromachined Disk Gyroscope

“…III. DEVICE The device-under-test in this study is a vacuum packaged micromachined disk gyroscope fabricated in a (100) single crystal silicon (SCS) substrate using a silicon-on-insulator (SOI) MEMS process employing wafer-level vacuum encapsulation [22]. The characterisation of resonant modes for this device has revealed several modes with quality factors exceeding a million [10], [15] and a Q-f metric exceeding 10 13 .…”

A Silicon MEMS Disk Resonator Oscillator Demonstrating 36 ppt Frequency Stability

“…The device-under-test in this study is a vacuum packaged micromachined disk resonator fabricated in a siliconon-insulator (SOI) MEMS process employing wafer-level vacuum encapsulation [2]. Figure 1 shows an optical micrograph of the device.…”

“…MEMS resonators and oscillators have been the focus of much interest in recent years for their usage in a wide range of diverse applications such as timing and frequency control [1], high-performance inertial sensors [2], chemical sensing [3] and biological sensing [4]. MEMS technologies demonstrate several advantageous features such as miniaturization, batch manufacturability, and close integration with CMOS electronics [1], [5], [6] making MEMS oscillators attractive alternatives to well established quartz-based oscillators for timing and frequency control applications.…”

Small Local Earthquake Detection Using Low-Cost MEMS Accelerometers: Examples in Northern and Central Italy

“…Recent advances in micromachined sensors provide adequate sensitivity for measurement in geophysical applications. For example, several MEMS devices are suitable for volcanic activity studies (Andò et al, 2011), gravimetric and geodetic observations (Cenni et al, 2019;Mustafazade et al, 2020), and seismological and earthquake engineering projects (Holland, 2003;Cochran et al, 2012). These sensors can reach an efficient performance for moderate (5:0 > M w > 5:9) to large (M w > 6:0) earthquake detection at distances on the order of tens of kilometres (Boaga et al, 2019;Liu et al, 2011).…”