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EARTHQUAKE ›› 1998, Vol. 18 ›› Issue (2): 206-210.

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THE IMMINENT INDEX OF AMPLITUDE-PHASE METHOD OF GEOMAGNETIC Z COMPONENT

Feng Zhisheng1), Wang Jianyu1), Jiang Yanlin2), Zhuang Minglong1）, Wu Huolin3）, Li Xingyuan4）   

  1. 1) Seismological Bureau of Jiangsu Province, Nanjing 210014, China;
    2) Gaoyou Seismic Station, Jiangsu 225600, China;
    3) Nanjing Seismic Station, Nanjing 210014, China;
    4) Liyang Seismic Station, Jiangsu 213300, China
  • Received:1997-06-23 Revised:1997-09-04 Online:1998-04-30 Published:2022-05-10

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Abstract: By using the daily variation data of geomagnetic Z component for seven years at Lianyungang station and Liyang station, and the earthquakes with ML > 5.0 in Jiangsu Province, we get the imminent index of amplitude-phase method that eliminated the annual variation with a linear detrending and twice detrending. The analysis shows that the above-mentioned index system has the advantage of less influenced of man made factors on anomaly judgement, compared with the existing method. However it is necessary to decrease the false prediction ratio.

Key words: Geomagnetic amplitude-phase, Imminent index, Detrending, Standard value