地震地磁效应的分形布朗运动的性质及应用  

A study on fractal Brownian motion of geomagnetic observations before large earthquakes

作　　者：李美[1] 卢军[1] 苏小忠 冯志生[3] 

机构地区：[1]中国地震台网中心,中国北京100045 [2]天水地震台,中国甘肃天水741020 [3]江苏省地震局,中国南京210014

出　　处：《地震学报》2009年第6期650-659,共10页Acta Seismologica Sinica

基　　金：地震科学联合基金(C07062)资助

摘　　要：重标极差分析法(R/S,rescaled range analysis method),是研究分数布朗运动及自然现象的自仿射分形的有力工具之一,对于所有时间序列分析都有着广泛的用途.通过对天水台绝对地磁观测Z分量数据序列R/S分析,计算分段数据序列的Hurst指数H发现,昆仑山口西MS8.1地震和汶川MS8.0地震震前2—3个月,H值减小,分维数D增大,相关系数C为负值.这一动态变化表明,地震前数据序列由持久性序列发展为反持久性序列,观测数据的成分发生了改变.这与地壳内部应力变化和岩石破裂实验结果相符.所以,这一动态变化过程可以看作是强震前的一种前兆信号.Rescaled range analysis （R/S） method is one of the good tools for studying fractal Brownian motion of time-series data and natural phenomena self-affine fractal,being applied widely for all time-series.In this paper,this method is used to analyze absolute geomagnetic Z component observations at Tianshui Observatory.The Hurst exponent H was calculated for each sub-sequence of data in specific time intervals.Our analysis result indicates that,2--3 months before Kunlun MS8.1 earthquake and Wenchuan MS8.0 earthquake,H value decreased and fractal dimension value D increased.Such dynamic variations manifest that the observations varied from persistent behaviour to antipersistent time-series before the earthquakes and the composition of the observed data changed.This variation is consistent with internal crustal stress change and rock failure experiment results.So we may view this dynamic variation as a premonitory symptom of the strong earthquakes.

关 键 词：R/S分析 地磁Z分量 HURST指数 分形维数 前兆信号 

分 类 号：P315.721[天文地球—地震学]