汶川M_S8.0、海地M_W7.0地震电磁信号小波能谱分析

Wavelet power spectrum analysis of the electromagnetic signals of Wenchuan M_S8.0 and Haiti M_W7.0 earthquakes

应用小波变换方法处理了2008年汶川MS8.0地震前后成都、江油台地电阻率观测数据及汶川地震、2010年海地MW7.0地震前后DEMETER卫星记录的电离层磁场观测数据,研究了地电阻率和电离层磁场的小波能谱及其相对变化.结果表明:①对应汶川大震前成都台N58°E测道地电阻率中期下降变化和短期上升变化的时段,地电阻率小波能谱相对变化显著增大,江油台N10°E测道地电阻率在主震前记录到了临震异常,在临近主震前后,电离层磁场特别是x分量的能谱及相对变化显著增大,展现了与汶川大震明显对应的地电阻率、电离层磁场变化的似同步异常;②在海地地震前夕,电离层磁场x,z分量的能谱也出现了显著增大的现象,类似于汶川大震前后电离层磁场的能谱增大变化.

Wavelet transform technique is applied to the analysis of geo-resistivity data observed at Chengdu and Jiangyou stations before and after Wenchuan Ms8. 0 earthquake in 2008 and the ionospheric magnetic field recorded by DEMETER satellite before and after the Wenchuan earthquake and the 2010 Haiti earth-quake, in order to study the wavelet power spectrum of geo-resistivity and iono- spheric magnetic field and its relative variation. Our analysis result suggests that ① the wavelet power spectrum and its relative variation increased greatly at the times when the geo-resistivity of N58°E channel of Chengdu station displayed its medium-term decrease and short-term increase, the impending anomaly was recorded on the N10°E channel of Jiangyou geo resistivity station and the wavelet power spectrum of x component of ionospheric magnetic field and its relative value increased distinctly before Wenchuan earthquake, showing typical Earth-space electromagnetic anomaly of geo-resistivity and ionospheric magnetic field; ② The wavelet power spectrum of x and z components of iono- spheric magnetic field and its relative variation also increased greatly before Haiti earthquake, similar to the increase before and after Wenchuan earth quake.