ИСТИНА

1. The optimal algorithm for detecting the second overtone of the first-degree normal mode of the Earth 2S1 mode in non-Gaussian noises and for estimating mode parameters is proposed. 2. The records of 15 IGETS superconducting gravimeters with duration of 20.8 days after the Great Sumatra Andaman Earthquake on December 26, 2004 were processed with this algorithm. 3. The degenerate frequency, the splitting parameter and triplet frequencies of the 2S1 mode have been evaluated based on the data of the Canberra station . 4. The comparison of our results with the theoretical models and the previous results of experimental determinations of the mode triplet frequencies has been done. 5. The quality factor of the 2S1 has been evaluated. The found value (is slightly less than the value determined by the PREM model.