Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

Modeling o f the TEC disturbances generated by seismogenic electric currents at different seasons potential equation with following parameters: the density j — 10 nA/m2, the acting area with sizes 250 x 4500 km (geomagnetic latitude x longitude). The center of the area with additional sources was located over the epicenter of the corresponding earthquake. The UAM calculated TEC disturbances relative to the quiet conditions (i.e. without any additional seismogenic electric currents) for the Haiti earthquake are presented in fig. 3. Positive and negative deviations of 40-50 % and 30—40 % were obtained at the areas to the east and to the west from the epicenter meridian respectively; the disturbances’ maximum located in the Southern (summer) hemisphere. The effects disappeared at night and reappear after sunrise. The form o f the modeled disturbances stretched along the geomagnetic meridian, while observed ones stretched along the parallel. Beside of this, a good agreement between the UAM calculated and GPS observed TEC disturbances was achieved. -40 -30 -20 -10 0 10 20 30 40 30“ 0 “ -30” •a s 60- 1 30' .Ы O’ с -30- ьо 5 -60‘ -30- 0‘ 30’ -30" 0" 30' -30‘ 0* 3C Magnetic longitude Fig. 3 UAM calculated TEC disturbances (%) for the Haiti (left) and Japan (right) earthquakes. Fig. 3 shows the calculation results of the TEC disturbances for the conditions corresponding to the Japan earthquake. The calculated positive and negative disturbances had the same positions relatively to each other and the epicenter meridian like in the previous case. The Great Tohoku earthquake took place in conditions close to spring solstice, and symmetry o f the modeled effects relative to the geomagnetic equator is clearly visible just like in the observational data. But some differences were found out. First of all, the magnitude of the UAM calculated TEC disturbances is 15-20 % less than the magnitude of the GPS observed deviations; and negative disturbances were not discovered in observations. Secondly, some differences conclude in position of the anomalies relative to the epicenter and magnetically conjugated area: the GPS observed anomalies located closer to the equator. It is natural to assume that deposit from other mentioned earthquakes had place and complicated result picture. The TEC disturbances symmetrical both the epicenter meridian and the geomagnetic equator were obtained in the UAM simulations by placing two sources o f the electric currents of opposite direction (towards the Earth and towards the ionosphere) on the opposite sides from the epicenter meridian (eastern and western) respectively. The result is presented in fig. 4. -4 0 -3 0 -20 -1 0 0 10 20 30 40 M agnetic longitude Fig. 4 UAM calculated TEC disturbances (%) for the configuration with external electric currents flowing to the Earth (denoted by star) and to the ionosphere (circle). Conclusion GPS observed TEC disturbances prior to the Haiti (January 12, 2010) and Japan (March 11, 2011) earthquakes with the focal zone at the same latitude were briefly described, and typical set of the ionospheric earthquake precursors’ features was revealed in both cases in terms of stability, magnetic conjugation and local time dependence of the 180“ -90“ 180» -90° Magnetic longitude 149