Physics of auroral phenomena : proceedings of the 40th annual seminar, Apatity, 13-17 March, 2017 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2017. - 143 с. : ил., табл.

“Physics o f Auroral Phenomena”, Proc. XL Annual Seminar, Apatity, pp. 108-111, 2017 © Polar Geophysical Institute, 2017 Polar Geophysical Institute COMPARISON OF THE IONOSPHERIC EFFECTS OF THE SPACE WEATHER AND SEISMOGENIC DISTURBANCES A.A. Namgaladze1, M.A. Knyazeva1, M.I. Karpov 1,2 1 Murmansk Arctic Slate University, Murmansk, Russia 2Immanuel Kant Baltic Federal University, Kaliningrad, Russia e-mail: namgaladze@yandex.ru A b stra ct. The ionosphere variations before M6.7 earthquake in India on January 3, 2016 have been analyzed. The earthquake has occurred after the series of magnetic substorms on December 31, 2015 and January 1, 2016. The relative total electron content (TEC) disturbances have been estimated using the global maps of the total electron content (GIM-TEC) and calculated numerically using the 3D global first-principle Upper Atmosphere Model (UAM) for the whole period including the days before, during and after the substorms. Numerical simulations were repeated with the seismogenic vertical electric currents switched on at the earthquake epicenter. The UAM calculations have reproduced general behavior of the ionosphere after the main phase of the geomagnetic storm on January 1, 2016 in the form of negative TEC disturbances propagating from high latitudes, especially strong in the Southern (summer condition) hemisphere. It was shown that the local ionospheric effects of seismic origin can be identified on the background of the global geomagnetic disturbances. These seismo-ionosphcric effects are visible as the nighttime regions with the additional negative TEC disturbances extending from the Eastern side of the epicenter meridian to the Western side, both in the observations and simulations. It was found that the vertical electric field and corresponding westward electromagnetic drift play a decisive role in the formation of the ionospheric precursors of this earthquake. In tro d u c tio n The ionosphere response to the seismic activity has been the subject of the numerous studies aiming at detection of the ionospheric precursors of earthquakes. One of the ionosphere parameters often used to study the ionosphere response to the earthquakes preparations is the TEC (total electron content) of the ionosphere obtained via the global position systems (GPS, GLONASS). The formation of the pre-seismic TEC disturbances was explained by the vertical electromagnetic [E x В] drift o f the F2-layer plasma under the action of the electric field generated in the ionosphere above the epicenter region ( Namgaladze et al., 2009). The abnormal electric fields with the intensity of several mV/m were detected by DEMETER above the regions with the enhanced seismic activity ( Zhang et al., 2014). Sorokin & Hayakwa (2013) and Namgaladze & Karpov (2015) considered these electric field as a result of the vertical electric current generated over the tectonic fault due to the separation and vertical transport o f the opposite charges driven by the non-electric forces, similar to the thunderstorm currents charging the ionosphere. The numerical simulations with the Upper Atmosphere Model (UAM) have shown that the vertical electric current of ~20 nA/m 2 is required to generate the local pre-seismic electric fields of several mV/m and create the TEC disturbances analogous to the observed ones (Namgaladze et al., 2013; Karpov et al., 2013). The global state of the ionosphere is affected by numerous influences including the solar and geomagnetic activities, meteorological events and anthropogenic sources. It also experiences normal seasonal, day-to-day and diurnal variations. Thus, it is very important to clearly identify the ionospheric disturbances associated with the seismic activity and separate them from the regular Space weather variations. Most, if not all, case studies and statistical analysis were conducted for the periods of the low solar and geomagnetic activities. In this study we analyze the ionosphere behavior for the period o f high geomagnetic activity in December 2015 and January 2016 followed by M6.7 earthquake in India on January 3, 2016. Here we try to distinguish the pre-seismic TEC variations from the effects of the magnetic storm using the GPS observations and the UAM numerical calculations. Methods M6.7 earthquake occurred at 23:05:22 UTC on January 3rd, 2016 with the epicenter 30km W of Imphal, India (24.804°N, 93.651°E). The geomagnetic conditions for the period before the earthquake are characterized by the two series of substorms on December 20-21 and December 31-January 1 with Kp >6 and Dst reaching -150nT and - lOOnT, respectively. We used the global ionospheric maps o f the TEC (GIM-TEC) to estimate the TEC disturbances relative to the quiet values for this period. In order to obtain the background values and exclude the disturbed TEC values due to the high geomagnetic activity, we have averaged the TEC for December 25-30. During this period Kp<3 most of the time, exceeding 4 once on December 26, and Dst has never changed more than 30 nT within a day. For numerical calculations of the TEC variations we use the three-dimensional global first-principle Upper Atmosphere Model (UAM) ( Namgaladze et al., 1998, 2013). The model covers the height range from 90 km to the 108