Abstract
An attempt has been made to search for the translational oscillations of the Earth’s solid inner core in the gravity measurements recorded with the superconducting gravimeters (SG) from the worldwide network of the Global Geodynamics Project (GGP). All the SG data were prepared and analyzed by the same method to remove accurately the signatures related to gravity tides, local barometric pressure, the Earth’s rotation, the long-term trend and so on. We obtained the estimations of the power spectral densities of each residual series and the estimations of the product spectral densities in the subtidal band (0.162–0.285 cph) were obtained by using a multi-station stacking technique after further eliminating atmospheric effects. The inner core translation triplet was detected in the subtidal band. We find 6 groups of signal with high signal-to-noise ratio that are consistent with the characteristics of the triplet, and 4 groups of the results that are close to the previous studies and the differences are less than 0.92%. It implies that the groups of signatures all have the possibility to be related to the inner core translational oscillations.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References Cited
Courtier, N., Ducarme, B., Goodkind, J., et al., 2000. Global Superconducting Gravimeter Observations and the Search for the Translational Modes of the Inner Core. Physics of the Earth and Planetary Interior, 117(1): 3–20
Crossley, D., Rochester, M., Peng, Z. R., 1992. Slichter Modes and Love Numbers. Geophysical Research Letters, 19(16): 1679–1682, doi:10.1029/92GL01574
Dahlen, F. A., 1968. The Normal Modes of a Rotating, Elliptical Earth. Geophysical Journal of the Royal Astronomical Society, 16(4): 329–367, doi:10.1111/j.1365-246X.1968.tb00229.x
Dahlen, F. A., Sailor, R. V., 1979. Rotational and Elliptical Splitting of the Free Oscillation of the Earth. Geophysical Journal of the Royal Astronomical Society, 58(3): 609–623, doi:10.1111/j.1365-246X.1979.tb04797.x
Hinderer, J., Crossley, D. J., Jensen, O. A., 1995. A Search for the Slichter Triplet in Superconducting Gravimeter Data. Physics of the Earth and Planetary Interior, 90(3): 183–195
Melchior, P., Ducarme, B., 1986. Detection of Inertial Gravity Oscillations in the Earth’s Core with a Superconducting Gravimeter at Brussels. Physics of the Earth and Planetary Interior, 42(3): 129–134
Merriam, J. B., 1992. Atmospheric Pressure and Gravity. Geophysical Journal International, 109(9): 488–500
Niebauer, T. M., 1988. Correcting Gravity Measurements for the Effects of Local Air Pressure. Journal of Geophysical Research: Solid Earth (1978–2012), 93(B7): 7989–7991, doi:10.1029/JB093iB07p07989
Peng, Z. R., 1997. Effects of a Mushy Transition Zone at the Inner Core Boundary on Slichter modes. Geophysical Journal International, 131: 607–617, doi:10.1111/j.1365-246X.1997.tb06602.x
Rieutord, M., 2002. Slichter Modes of the Earth Revisited. Geophysics of the Earth and Planetary Interiors, 131(3): 269–278
Rochester, M., Peng, Z. R., 1993. The Slichter Modes of the Rotating Earth: A Test the Sub-Seismic Approximation. Geophysical Journal International, 113(3): 575–585, doi:10.1111/j.1365-246X.1993.tb04653.x
Rogister, Y., 2003. Splitting of Seismic-free Oscillations and of the Slichter Triplet Using the Normal Mode Theory of a Rotating, Ellipsoidal Earth. Geophysics of the Earth and Planetary Interiors, 140(1): 169–182
Rosat, S., Hinderer, J., Crossley, D., et al., 2003. The Search for the Slichter Mode: Comparison of Noise Level of Super conducting Gravimeters and Investigation of a Stacking Method. Physics of the Earth and Planetary Interior, 140(1): 183–202
Slichter, L. B., 1961. The Fundamental Free Mode of the Earth’s Inner Core. Proceedings of the National Academy of Sciences, USA, 47(2): 186–190
Smith, M. L., 1976. Translational Inner Core Oscillations of for a Rotating, Slightly Elliptical Earth. Journal of Geophysical Research, 81(17): 3055–3065, doi:10.1029/JB081i017p03055
Smylie, D. E., Rochester, M. G., 1981. Compressibility, Core Dynamics and the Subseismic Wave Equation. Geophysics of the Earth and Planetary Interiors, 24(4): 308–319
Smylie, D. E., 1992. The Inner Core Translational Triplet and the Density near the Earth’s Center. Science, 255(5052): 1678–1682, doi:10.1126/science.255.5052.1678
Smylie, D. E., Jiang, X., Brennan, B. J., et al., 1992. Numerical Calculation of Modes of Oscillation of the Earth’s Core. Geophysical Journal International, 108(2): 465–490, doi:10.1111/j.1365-246X.1992.tb04629.x
Smylie, D. E., Jiang, X., 1993. Core Oscillations and Their Detection in Superconducting Gravimeter Records. Journal of Geomagnetism and Geoelectricity, 45(11–12): 1347–1369
Smylie, D. E., 1999. Viscosity near Earth’s Solid Inner Core. Science, 284(5413): 461–463, doi:10.1126/science.284.5413.461
Sun, H. P., Xu, J. Q., Ducarme, B., 2004. Detection of the Translational Oscillation of the Earth’s Solid Inner Core Based on the International SG Observations. Chinese Science Bulletin, 49(11): 1165–1176, doi:10.1360/03wd0242
Tamura, Y., 1987. A Harmonic Development of the Tidal Generating Potential. Bull. Inf. Marées Terrestres, 99: 6813–6855
Vauterin, P., 1998. Tsoft: Graphical and Interactive Software for the Analysis of Earth Tide Data. In: Proc. 13th Int. Sympos. on Earth Tides, Brussels. 481–486
Wenzel, H. G., 1996. The Nanogal Software: Data Processing Package ETERNA 3.3. Bull. Inf. Marées Terrestres, 124: 9425–9439
Xu, J. Q., Sun, H. P., Fu, R. S., 2005. Detection and Study of the Translational Oscillations of the Earth’s Solid Inner Core. Advances in Earth Science, 20(7): 740–745 (in Chinese with English Abstract)
Xu, J. Q., Sun, H. P., Zhou, J. C., 2010. Experimental Detection of the Inner Core Translation Triplet. Chinese Science Bulletin, 55(3): 276–283
Author information
Authors and Affiliations
Corresponding author
Additional information
This study was supported by the National Natural Science Foundation of China (Nos. 41021003 and 41074053).
Rights and permissions
About this article
Cite this article
Jiang, Y., Xu, J. & Sun, H. Detection of inner core translational oscillations using superconducting gravimeters. J. Earth Sci. 24, 750–758 (2013). https://doi.org/10.1007/s12583-013-0370-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12583-013-0370-x