Attenuation of free spheroidal oscillations of the Earth after the M = 9 Earthquake in Sumatra and the super-deep Earthquake in the Sea of Okhotsk: I. the Admissible Q-factor range for the fundame

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• 作者：S. M. Molodenskii ; M. S. Molodenskaya
• 刊名：Izvestiya, Physics of the Solid Earth
• 出版年：2015
• 出版时间：November 2015
• 年：2015
• 卷：51
• 期：6
• 页码：821-839
• 全文大小：1,375 KB
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  Molodenskii, S.M. and Molodenskii, M.S., On the admissible range for the mass and inertia moments of the liquid core: I. Solving the inverse problem of nutations and free oscillations of the Earth by decomposition of mechanical parameters in an orthogonalized basis, Izv., phys. Solid Earth, 2013a, vol. 49, no. 4, pp. 449-58.CrossRef
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  Molodenskii, S.M., Molodenskii, M.S., and Molodenskaya, M.S., The density and Q-factor models based on the new data on the nutations and overtones of the free oscillations of the Earth: 1. The analysis of the new GSN data for the Sumatra, Tohoku, and Okhotsk earthquakes, Izv., phys. Solid Earth, 2014a, vol. 50, no. 5, pp. 603-10.CrossRef
  Molodenskii, S.M., Molodenskii, M.S., and Molodenskaya, M.S., The density and Q-factor models based on the new data on the nutations and overtones of the free oscillations of the Earth: 2. The results of the numerical modeling?of the solution of the inverse problem, Izv., phys. Solid Earth, 2014b, vol. 50, no. 4, pp. 611-21.CrossRef
  
• 作者单位：S. M. Molodenskii (1)
  M. S. Molodenskaya (1)
  
  1. Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, ul. Bol’shaya Gruzinskaya 10, Moscow, 123995, Russia
  
• 刊物主题：Geophysics/Geodesy;
• 出版者：Springer US
• ISSN：1555-6506

文摘

The problem of reconstructing the depth distribution of density and the depth and frequency dependences of the mechanical Q-factor in the Earth’s mantle from the entire set of the present-day seismic and astrometric data on the travel times and periods of seismic waves and the amplitudes and phases of forced nutations is considered. The solution of the problem is refined by including the new data about the attenuation of the free oscillations of the Earth excited by the Sumatra earthquake (M = 9) and super-deep earthquake in the Sea of Okhotsk. The actual accuracy of the Q-factor is studied in the first part of the paper. To this end, we analyze (1) the convergence of the Q-factor estimated from the time series of different length shifted along the time axis and (2) the convergence of the results based on the different data. Since the accuracy of identifying all the periods and attenuation factors for the free oscillations from the Sumatra earthquake is significantly higher than for the earthquake with M = 9 in Japan, the data are only compared for the Sumatra and Okhotsk events. The signal-to-noise ratio (SNR) is analyzed based on the records from different Global Seismographic Network (GSN) stations including the station in Obninsk, the Kurchatov station in Kazakhstan, and the main ERM and MAJO stations in Japan. It is found that the highest SNR was observed in Obninsk. The inverse problem of reconstructing the density and Q-factor is solved for the frequency dependent real parts of the shear moduli with allowance for the most accurate data about the attenuation factors for the fundamental spheroidal modes of the free oscillations of the Earth. Original Russian Text ? S.M. Molodenskii, M.S. Molodenskaya, 2015, published in Fizika Zemli, 2015, No. 6, pp. 24-2.