ИСТИНА

N-wave type variations of Total Electron Content (TEC), registered via GPS during the first 15 minutes after the seismic event, are observed as the ionospheric response to the transition of acoustic waves, generated during the strong (Mw ≥8.2) submarine earthquakes. The coseismic variations of TEC are filtered in acoustic diapason of 120 - 720 s and the means of the duration of the positive phase of the shock wave pulse t+ are calculated for the set of the strongest tsunamigenic earthquakes, occurred between the years 2003-2015. The particular features of the N-wave shape ionospheric response depend on 1) the seismic moment M0 and hence the radiated seismic energy Es of the event, - the stronger earthquakes have bigger amplitude and shorter duration of the compression phase; 2) the angle of the incidence of acoustic rays, coming from the source of perturbations, with the geomagnetic field at ionospheric heights, – the maximum amplitude is observed where the vectors of the acoustic ray and geomagnetic field have the same direction; 3) geomagnetic impact on the propagation of the signal in the ionosphere, - signal propagation toward the geomagnetic equator is amplified and toward the geomagnetic pole is suppressed[1]; 4) distance of the subionosperic point, where the maximum of perturbations in TEC variations is registered, from the epicenter of the seismic event [2] and relative position of the ray of acoustic perturbations and the line-of-sight between the GPS-receiver and the satellite. We used the least squares (LS) approximation for calculation of the regression of the average duration of the positive phase t+ on the seismic energy of the submarine earthquakes Es. Information on Es was taken from USGS catalogue of the earthquakes and from estimation in [2], inferred from the duration of the compression phase of the shock wave in TEC variations. LS-estimates of the RMS deviation indicate the fair accuracy of the approximation, which allow to consider the inverse problem of determination of the radiated seismic energy of the tsunamigenic earthquake from the measures of the positive phase duration of the N-wave TEC-response, thus provide the additional information for Tsunami Early Warning System.