STUDY ON THE RELATIONSHIP BETWEEN SEISMO-MAGNETIC EFFECTS AND SEISMICITY IN WEST GANSU AND ITS ADJACENT AREA WITH HIGHER-ORDER STATISTICS

Higher-Order Statistics (HOS) is a useful tool for studying non-Gaussian process, non-minimum phase system and nonlinear systems.The HOS method has been applied widely in different fields such as communication, geophysics, biomedical, failure diagnosis etc.the data of geomagnetic vertical component in Jiayuguan and Qianling Seismostation from 1998 to 2002 is processed with HOS method, and the relationship between the seismicity and the variations of geomagnetic field in west Gansu and its adjacent area is discussed.Through comparing the results with those from correlative analysis and linear fitting we found that the anomalies of HOS appeared 1~2 months earlier than those of correlation coefficient and linear fitting before an earthquake.Usually, the variation of third order moment anomaly (third order cumulant) is from 5 to 10, and of the fourth order is from 10 to 60.The magnitude of fourth order moment anomalies is over 50, sometimes even reach 150.The results show it is significant to introduce HOS method into the statistics of seismo-magnetic effect.