Comparative Study Between Electromagnetic Disturbances And Electromagnetic Phenomena In Space

In this thesis, the great and strong earthquakes occurred near the Tibetan Plateauand the foreign typical earthquakes during2007~2010were taken as research object.The phenomenon of the electromagnetic radiation before and after earthquakes arestudied with the observed data from electromagnetic disturbance stations,China-French International Cooperation geo-electric field stations which is close toearthquakes’epicenter and the magnetic field observations data of Demeterelectromagnetic satellite in ionosphere. The non-linear power spectrum estimationmethod (Maximum entropy method, for short “MEM”) and the statistical methods ofthe electric/magnetic field pulse energy are used in the study. The data of thegeo-electric field, geo-magnetic field minute values observation data from5electromagnetic disturbance stations and a China-French International Cooperationgeo-electric field stations are mainly used to study the Pu’er earthquake with Ms6.4,the Yutian earthquake with Ms7.3, the Wenchuan earthquake with Ms8.0and theYushu earthquake with Ms7.1prior to one year and after half a year of the event.,. Thedata from space-based observation within the epicenter about2000km are used toPu’er event, Yutian event, Wenchuan event, Yushu event, Haiti and Chile events.1068consecutive tracks (Night upward track) and the93repeat tracks around theWenchuan area are included. The sampling rate of the Ionosphere magnetic fieldobservations is2500Hz, the data length of time series of continuous track is the sixmonths before and a few months after the earthquake. The repeat track is4year.According to the results, we obtained several conclusions and cognitions as following:(1) In the impending stage of the Wenchuan and Yutian earthquake (including thestrong earthquake near the region), the ground electromagnetic disturbance stationslocated at the eastern margin of Qinghai-Tibet Plateau recorded the low frequencysignals of the spectrum density and electromagnetic pulse energy from the records ofelectric and magnetic field with frequency>0.002Hz. In the impending stage of theYushu earthquake, there have been very low frequency components on the records ofpower spectrum density in the Daiqian station of China-French InternationalCooperation observation in the northeastern margin of Qinghai-Tibet Plateau. (2)1to16days before the Wenchuan, the Yutian, the Yushu, the Puer, and theQingchuan earthquakes, a month before the Chile earthquake, the Demeterionospheric magnetic field observations recorded the extremely low frequencycomponents with frequency>40Hz the increasing spectral density. Meanwhile, theionosphere magnetic field pulse energy significantly increased.(3) It is the first time to obtain the synchronous change of the ionospheremagnetic field and the ground electric field/magnetic field associated with thephenomenon of extremely low frequency strong electromagnetic radiation on the eveof the earthquake. The power spectral density of ionospheric magnetic field enlargedtime roughly corresponded to the spectral density of the ground magnetic fielddisturbance increased time during the Wenchuanand Yutian earthquakes. The spectraldensity of ionospheric magnetic field and the ground electric field increased time wasconsistent on the eve of the Yushu earthquake. The pulse energy of ionosphericmagnetic field enlarged time roughly corresponded to the ground electric field andmagnetic field increased time during the Wenchuan and Qingchuan earthquakes. Theintegration of Space-Earth electromagnetic phenomena makes the change of electric/magnetic field information more reliable. The seismic electromagnetic phenomenacan be observed in space.(4) The spectral density begins to decrease about two month before the Haitiearthquake, the research results was not consistent with the several domesticearthquakes and the Chile earthquake. The magnetic field spectral density, pulsefrequency and pulse energy of Demeter repeat orbit change are complicated aroundthe Wenchuan earthquake epicenter, almost no credible anomalies corresponding tothe earthquakes. In contrast, the earthquakes did not occur in the region which wascovered by the satellite orbit during abnormal periods. These phenomena show thecomplexity of the space magnetic field changes.(5) In the impending stage of the Wenchuan, Yutian and Yushu earthquake(including the strong earthquake near the region), the increasing phenomenon of thegeo-electric field, geo-magnetic field spectral density and pulse energy mightimplicate the extremely low frequency component of the geo-electric/geo-magneticfields is rich and the electromagnetic radiation energy is strong on the eve of earthquake. The causes of the phenomenon of strong electromagnetic radiation couldbe explained by the following viewpoints. The loading environment might be theprocess of the nonlinear development, the medium direction arrangement occurredfrom the underground medium internal micro-cracks, synchronous"machine-electricity conversion", water transport, and other factors caused by strongelectromagnetic radiation. The phenomena of the ground electromagnetic radiationtransmitted to the ionosphere and the coupling mechanism needs further study, whichis still not clear at present.