Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-03T01:38:27.459Z Has data issue: false hasContentIssue false
  • English
  • Français

The Geophysical Interpretation of Changes in the Length of the Day and Polar Motion

Published online by Cambridge University Press:  14 August 2015

S.K. Runcorn
S.K. Runcorn*
Affiliation:
School of Physics, The University, Newcastle upon Tyne, NE1 7RU, U.K.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The data on the irregular fluctuations in the length of the day and the motion of the pole is of great significance in the geophysicist's task of constructing a model of the earth's interior.

Short term instabilities in the dynamo generating the earth's magnetic field produce what is observed at the surface as the secular variation. These changes induce currents in the lower mantle and the resulting torques appear to be the cause of the irregular fluctuations in the length of the day, although some quantitative problems remain.

The excitation of the Chandler wobble could result from impulsive torques applied to the mantle by very short period (a year or less) local magnetic field disturbances coming to the surface of the core. The alternative mechanism by earthquakes has been much investigated and the possibility of this is still obscure. A test however is available in the polar motion data: a disturbance in its path displaces the subsequent centre of its Chandler motion in the latter theory, but only its amplitude on the former theory. The behaviour of the pole around 1968 supports the core theory, but much more analysis of the polar motion is required.

Type
Part VIII: Geophysics
Information
Symposium - International Astronomical Union , Volume 82: Time and the Earth's Rotation , 1979 , pp. 301 - 306
Copyright
Copyright © Reidel 1979 

References

Bauer, L.A. 1895. Amer. J. Sci. 50, pp. 109, 189,314.CrossRefGoogle Scholar
Brouwer, D. 1952.Astron. J. 57, pp. 125.Google Scholar
Cazenave, A. & Lambeck, K. 1976.Geophys. J. Roy. Astr. Soc. 46, pp. 555.Google Scholar
Guinot, B. 1972.In Rotation of the Earth, IAU Symposium No. 48, Eds.Melchior, P. and Yumi, S., D. Reidel Publishing Co. pp. 46.Google Scholar
Halley, E. 1692.Phil. Trans. Roy. Soc. 17, pp. 563.Google Scholar
Hide, R. 1969.Nature, 222, pp. 1055.CrossRefGoogle Scholar
Jones, H. Spencer, 1939, Mon. Not. Roy. Astr. Soc. 99, pp. 541.CrossRefGoogle Scholar
Kahle, A.B., Ball, R.H. & Cain, I.C. 1969.Nature, 223, pp. 165.CrossRefGoogle Scholar
Lambeck, K. 1968.Phil. Trans. Roy. Soc. A287, pp. 545.Google Scholar
Markowitz, W. 1968.In Continental Drift, Secular Motion of the Pole and Rotation of the Earth, IAU Symposium No. 32, Eds. Markowitz, W. and Guinot, B., D. Reidel Publishing Co. pp. 25.CrossRefGoogle Scholar
Mintz, Y. & Munk, W.H. 1951.Tellus, 3, pp. 117.CrossRefGoogle Scholar
Morrison, L.V. and Ward, C.G. 1975.Mon. Not. Roy. Astr. Soc. 173, pp. 183.CrossRefGoogle Scholar
Muller, P.M. 1976.Report SP43-36, Jet Propulsion Laboratory, California.Google Scholar
Muller, P.M. & Stephenson, F.R. 1975.In Growth Rhythms and the History of the Earth's Rotation, Eds. Rosenberg, G. D. and Runcorn, S. K., John Wiley and Sons, pp. 459.Google Scholar
Pannella, G. 1975.In Growth Rhythms and the History of the Earth's Rotation, Eds. Rosenberg, G. D. & Runcorn, S. K., John Wiley & Sons, pp. 253.Google Scholar
Roberts, P.H. 1972.J. Geomag. and Geoelec. 24, pp. 231.Google Scholar
Rochester, M.G. 1960.Phil. Trans. Roy. Soc. A252, pp. 531.Google Scholar
Roden, R.B. 1963.Geophys. J. Roy. Astr. Soc. 7, pp. 361.CrossRefGoogle Scholar
Rosenberg, G.D. and Runcorn, S.K.(Eds.)1975.Growth Rhythms and the History of the Earth's Rotation, John Wiley and Sons.Google Scholar
Runcorn, S.K. 1955.Trans. Amer. Geophys. Un. 36, pp. 191.Google Scholar
Runcorn, S.K. 1969.Science, 163, pp. 1227.Google Scholar
Runcorn, S.K. 1970.In Earthquake Displacement Fields and the Rotation of the Earth. Eds. Manshinha, L., Smylie, D.E. and Beck, A.E. D. Reidel Publishing Co. pp. 181.CrossRefGoogle Scholar
Sitter, W.de 1927.Bull. Astron. Inst. Neth. 4, pp. 21.Google Scholar
Vestine, E.H. 1953.J. Geophys. Res. 58, pp. 127.Google Scholar
Vestine, E.H., Laporte, L., Large, I., Cooper, C. and Hendrix, W. 1947. Description of the Earth's Main Magnetic Field and its Secular Change, 1905–1945.Carnegie Inst. Wash. Publ. 785.Google Scholar