Mining for seismomagnetic information of geomagnetic Z component based on Copula theory
Zhang Mingdong
Zhang Wenlei
Cao Jingquan
Wang Jianguo
Tan Qing
Zhang Wei
Abstract：In this paper,we selected geomagnetic data of five seismographic sta-tions in Tianjin,analyzed and calculated geomagnetic Z component data from 1986 to 2013 based on Copula theory. After comparison of Kendall and Spearman coefficients in a variety of models,the optimal model was got,and then Kendall coefficient timing curves were analyzed in different cycles.The calculated results show that Kendall coefficient timing curve is in the disordered phase before the MS≥5 .0 earthquake,and its consistency turns better rapidly after the earthquake.That is because the accumulated seismic stress causes the underground electrical structure to change,and the stress is released after the earthquake,magnetic field data returns to normal.It is more predominant that Kendall coefficient of the Qingguang seismographic station (it has the smallest distance from the epicenter)dropped sharply before the Wen’an MS5.1 earth-quake in 2006 ,which is different from that of other stations;while Kendall co-efficient of the Ninghe seismographic station (it has the smallest distance from the epicenter)rose marginally before the Tangshan MS4.8 earthquake in 2012.
Keywords：Copula functionKendall coefficientSpearman coefficientmodel testunderground electrical structure
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：14( 930-943 )