Journal of the Japan Society of Engineering Geology
Online ISSN : 1884-0973
Print ISSN : 0286-7737
ISSN-L : 0286-7737
Volume 59 , Issue 2
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Original Article
  • Takao AIZAWA, Takashi KUNIMI, Shunichiro ITO, Kazunori MURATA, Toru SE ...
    2018 Volume 59 Issue 2 Pages 84-93
    Published: June 10, 2018
    Released: August 26, 2019
    JOURNALS FREE ACCESS

    The authors have developed the high resolution MEMS accelerometer for seismic exploration, as an alternative receiver to conventional geophones. The sensitivity of MEMS sensors in the consumer market is so low that they cannot be used for seismic exploration. We developed a new model. To improve the sensitivity, it is necessary to increase the range of variation of capacitance. This was overcome by increasing the size of the electrodes. For the purpose of solving the problems associated with increasing the size of moving electrode, a simulation was run and confirmed the effects of the shape of the beam support, the beam thickness, the inter-electrode gap, sticking, the gas viscosity and the influence of Brownian noise. A design specification was set not to cause sensitivity error in the frequency band 0 ~ 250 Hz. The circuit to drive the elements was designed to work digitally in reading capacitance change, filtering and outputting. A performance test we carried out included the noise evaluation test, and confirmed that the noise level was below -130 dB /√Hz. Asa field performance test, we carried out a 4 km long reflection seismic survey in Sanmu City in Chiba Prefecture, comparing a the newly-developed prototype MEMS, conventional geophones and commercial highsensitivity MEMS sensors. The result showed the seismic sections by the three sensors are similar, despite the differences in the season and the conditions of sensor installat ion.

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