The paper presents the results of a study of variations in ionospheric parameters and local magnetic constant before, during, and after the Вachat earthquake, which occurred on June 18, 2013 at 23:02 UT (June 19, 2013 at 06:02 LT) with a magnitude 5.3–5.6 and epicenter coordinates 54.29° N, 86.17° E. We have used data from IPGG SB RAS and TSU ionospheric stations and INTERMAGNET geomagnetic observatories. We have established that in the period preceding the earthquake there was a rather sharp increase in the magnetic moment, and in the subsequent period there was an equally sharp decrease in the magnetic moment. It is noted that the analysis of the daily average values of the local magnetic constant is the most promising for searching for geomagnetic precursors of earthquakes. We have found a low strong sporadic layer Es for two days before the event, the like of which was not observed for 15 days before and 15 days after the event. In addition, on the days preceding the shock, the background values of the F2-layer critical frequency were larger by more than 20 % at the local pre-event hours. On the second day after the earthquake, there appeared a night-time region of low values (about 14 %), which persisted until the morning of the third day.
earthquake, ionosphere, sporadic ionospheric layer, local magnetic constant
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