Abstract: Five frequency bands of the power spectrum density data of the electric field in the ELF/VLF frequency band (39~6000 Hz) recorded by the microsatellite DEMETER from January 2005 to February 2009 is utilized to carry out statistical analysis about the spatio-temporal evolutions of electric field during the 8 strong earthquakes with magnitude M_S≥5.0 in Northeast Asia (38°N~58°N; 105°E~145°E). The analysis shows the perturbations in different frequency bands of the same earthquake are not all in the same regions. And the perturbation patterns in different frequency bands of the same earthquake are not consistent during the same earthquakes. Statistical analysis of perturbation amplitude during the 8 earthquakes shows that for the 25% of these statistics shows no obvious spatial and temporal patterns, although the perturbation amplitude reached basically more than 2 times the standard deviation during the earthquakes. The remaining 75% of the statistics can be classified into three types: the perturbation amplitude of the 52% of the statistics began to increase before the earthquake, and the earthquake occurred at the high perturbation stage. For the 7.5% of the statistics, the perturbation amplitude increased to the high perturbation stage before the earthquake, and the earthquake occurred during the descent stage of the perturbation amplitude. For the 15% of the statistics, the perturbation amplitude increased and reached basically less than 2 times the standard deviation before the earthquake, and the perturbation amplitude of the fifth frequency band in these earthquakes are all in this type. The perturbations mainly appear in the places outside ±4° in latitude and in longitude from theepicenter.

Key words: The microsatellite DEMETER, ELF/VLF electric field power spectrum, The Northeast Asia region, Spatio-temporal evolution, Abnormal perturbation