A High-Consistency Broadband MEMS-Based Electrochemical Seismometer With Integrated Planar Microelectrodes

This paper presents a broadband micro-electromechanical systems-based electrochemical seismometer with a new sensing unit composed of planar microelectrodes and perpendicular flow channels. The proposed sensing unit only needs three main microfabrication steps, leading to high consistency among devices which was quantified as 0.9978 ± 0.00050. Moreover, due to the new structure of the propose sensing unit, the raw device was featured with higher sensitivity [215.5 V/(m/s)], lower central working frequency (1 Hz), and wider working bandwidth (0.12–10.5 Hz) than previous reports. Based on the wide raw bandwidth, a broadband electrochemical seismometer was developed by the force balancing negative feedback with the final working bandwidth of 4.2 decades (0.0071–113 Hz). The linearity error and total harmonic distortion were both decreased by the feedback technology. In addition, the proposed devices demonstrated comparable self-noise level with the high-performance commercial counterpart “Trillium Compact.” Random seismic recording test was also conducted where the proposed device recorded a local earthquake with high consistency with the STS-2.5 deployed in the permanent station.