Research on Magnetoelectric Seismometer's Low Frequency Extension Technology

Abstract:

Magnetoelectric seismometer has many outstanding features, such as low cost, small size, light weight, high sensitivity, low noise, good high frequency response, and reliable operation, simple set up, so these type of seismometer is widely used in several areas. However, because the structure of magnetoelectric seismometer (inertial mass and elastic support module), there has the material and mechanical structure limitation, so the inherent frequency is around between 5 to 30Hz, hard to be lower, hence, the low frequency characteristic is poor. To extend the seismometer's range of application, post compensation is needed. The researchers from both home and aboard proposed many different method to deal with the low frequency response of this seismometer, such as “inverse filter” method, “Lippmann” method, which uses negative resistance and feedback coil. These methods have got some results separately. In this paper, we will propose a low frequency integral method to extend the seismometer's frequency response. It is accomplished through balanced integration and high precision chips to suppress the circuit drifting and noise interference. The results from vibration table shows, after integration, the seismometer's low frequency corner frequency is extended from 2 Hz to under 0.1 Hz, the sensitivity is enhanced from 200V/m·s^-1 to 400V/m·s^-1.

• Periodical: Applied Mechanics and Materials (Volume 664)
• Pages: 268-273
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.664.268
• Online since: October 2014
• Authors: Yun Tian Teng, Xing Xing Hu, Hong Ya Lu
• Keywords: Balanced Integration, Low Frequency Corner Frequency, Low Frequency Extension, Magnetoelectric Seismometer, Zero Drift

References

[1] He Zhengqin, Ye Tailan, Ding Zhifeng, Sun Weiguo. The application of shallow seismic prospecting methods to active fault detection if cities. 2001, (1): 1-6.

[2] Yu Shuibao, Li Minghua, Lu Zhenhong. Rearch of frequency bandspread of magnet-electrical absolute vibration velocity transducer. Journal of Zhejiang Normal University(Nat. Sci. ), 1999, 22(1): 22-27.

[3] Jia hui, He Zhenqin, Ye Tailan. Application of SASW and MASW to buried fault detection. Progress in Geophys, (in Chinese), 2010, 25(2): 709-713, DOI: 10. 3969/j. issn. 1004-2903. 2010. 02. 046.

[4] Sun Yongjun, Xu Peifeng, Lin Squn, Li Chuangjin. Microtremor survey method and its progress. Progress in Geophys. (in Chinese), 2009, 24(1): 326-334.

[5] Hagami H, Duke C M, Liang G C, Ohta Y. Evaluation of site effect upon seismic wave amplification due to extremely deep soil deposits. Bull. Seism. Soc. Am., 1982, 72: 987-998.

DOI: 10.1785/bssa0720030987

[6] Wang Weijun, Liu Lanbo, Chen Qifu, Zhang Jie. Applications of microtremor H/V spectral ratio and array techniques in assessing the site effect and near surface velocity structure. Chinese J. Geophys. (in Chinese), 2009, 52(6): 1515-1525, DOI: 10. 3969/j. issn. 0001-5733. 2009. 06. 013.

[7] Kase. S, Katon.J. A seismic displacement sensor for rotarional vibration with measuring range enlarged to the low-frequency region. Transactions of the Japan Society of Mechanical Engineers. C, 1990, 56(524): 906-910.

DOI: 10.1299/kikaic.56.906

[8] Henri P. Gavin, Rodrigo Morales, Kathryn Reilly. Drift-free integrators. Review of Scientific Instruments, 1998, 69(5): 2171-2175.

DOI: 10.1063/1.1148918

[9] E.J. Rogers. Integrator for small pulsed and direct currents. The Review of Scientific Instruments, 1963, 34(6): 660-663.

DOI: 10.1063/1.1718533

[10] J.G. Bak, S.G. Lee, and the KSTAR Project Team. Performance of the magnetic sensor and the integrator for the KSTAR magnetic diagnostics. Review of Scientific Instruments, 2004, 75(10): 4305-4307.

DOI: 10.1063/1.1789620

[11] Hu Xingxing, Teng Yuntian, Xie Fan, Wang Xizhen, Li Caihua, Wang Xiaomei. Research on MEMS velocity seismometer technology. Progress in Geophysics, 2013, 28(1): 515-522.

[12] Wei Yongqing, Xie Jikang, Wan Baonian, Shen Biao. A chopper-stabilized long pulse integrator with low drift. Nuclear Fusion and Plasma Physics, 2006, 26(3): 246-251.

[13] Wu Zhaofang. Auto-compensation of the integrator's drift. Journal of Anqing Teachers College (Natural Science Edition), 2008, 14(2): 28-30.

[14] E. J. Strait, J. D. Broesch, R. T. Snider, M. L. Walker. A hybrid digital-analog long pulse integrator. Rev. Sci. Instrum. 1997, 68(1): 381-384.

DOI: 10.1063/1.1147835

[15] J. G. Bak, S. G. Lee. Analog integrator for the Korea superconducting tokamak advanced research magnetic diagnostics. Review of Scientific Instruments, 78, 043504 (2007).

DOI: 10.1063/1.2721405

[16] Li Xiangyang, Zhou Jing, Dong Wei. Design of high precision and low drift electronic integrator. China Measurement Technology, 2007, 33(6): 137-140.

[17] Liu Dongmei, Wan Baonian, Shen Biao. Design of a long pulse and low drift analog integrator in HT-7. Nuclear Electronics & Detection Technology, 2007, 27(3): 447-469.

[18] Wang Yong, Ji Zhenshan, Luo Jiarong. Design of low drift integrator with auto-compensation. Computer Measurement $ Control, 2006, 14(4): 530-532.

[19] Giovanni Romeo. Whale watching: effects of strong signals on Lippmann style seismometers. Journal of Seismology, 2012, 16(1): 25-34. DOI: 10. 1007/s10950-011-9246-7.

DOI: 10.1007/s10950-011-9246-7

[20] Romeo, G. and Spinelli, G.: Extending a Lippmann style seismometer's dynamic range by using a non-linear feedback circuit, Adv. Geosci., 36, 27-30, doi: 10. 5194/adgeo-36-27-2013, (2013).

DOI: 10.5194/adgeo-36-27-2013