Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.

Wave disturbances in the lower ionosphere during the earthquakes on August 2006 amplitude of partial-reflected signal is broader, than spectrum of the amplitudes on August 7. In figure 5 daily variations of least frequency of reflection fmin with the hour resolution on August 7-9 and 10-12, 2006 are submitted. The fluctuations of the amplitude of the least frequency fmin on August 7 at station of the vertical sounding of the ionosphere at Sodankyla increased till 3 MHz before beginning of the earthquakes and after it. On August 11 the fluctuations of the amplitude least frequency of fmin increased till 1.5 MHz before beginning of first earthquake. Full absorption of waves (B) in the ionosphere was observed on August 8 at 6 LT, 10-12 LT, 14 LT. 107.08.2006^08.08.2006 0 9 .0 8 .2 0 0 6 •£ £ 2 f! 4 I - I M u v U l » U J U w 4 - 0 L n ^ 4 j 1 0 . 0 8 . 2006 ] ! 1 . 08. 20 06 1 2 . 0 8.2006 u . 12 24 12 24 12 24 H ou rs, LT О 12 24 12 24 12 24 H o u r s , L T Fig. 5. Daily variations least frequency fmin on August 7-9 and 10-12, time LT=UT+2 hours (▼-time of the earthquakes beginning). Daily spectra amplitudes of the least frequency fmin in days of the earthquakes on August 7 and 11, 2006 are submitted in figure 6. In spectrum of the amplitudes of the fluctuations of the least frequency of reflection (fmin) on 7.08 the tidal atmospheric waves since periods of 16 and 11 hours were observed along with internal gravity waves since periods of 2-4 hours. On 11.08 under high solar activity in spectrum of the fluctuations fmin amplitudes together with tidal atmospheric waves with the periods o f 8 hours, also internal gravity waves periods of 2-4 hours were observed. io5i „ . i fmin 11.08,2006 00:00-23:00 Frequency, Hz Frequency, Hz Fig. 6. Daily spectra amplitudes of the least frequency fmin on August 7 and 11,2006. The similar fluctuations o f critical frequency foEs amplitudes of sporadic layer were observed. In spectra of the amplitudes foEs in the evening and morning on7.08. and 11.08.2006, together with tidal atmospheric waves with periods of 15, 11 hours, also internal gravity waves periods of 2-6 hours were observed (fig.7). io5 , | i 104 103 105-q f o E s 0 7 -0 8 .0 8 .2 0 0 6 1 7 :0 0 -0 5 :0 0 1 i 104 103 f o E s 1 1 -1 2 .0 8 .2 0 0 6 1 8 :0 0 -0 6 :0 0 10-' 10- 1 0 .5 io-4 io-3 io-6 io-5 io-4 F r e q u e n c y , H z F r e q u e n c y , H z Fig. 7. Spectra of the amplitudes o f sporadic layer foEs in the evening and morning on 7.08. and 11.08.2006. Time LT=UT+2 hours. 149