Earthquake Displacement Fields and the Rotation of the Earth: A NATO Advanced Study Institute

ISBN-13: 9789401033107 / Angielski / Miękka / 2013 / 310 str.

L. Mansinha; D. E. Smylie; A. E. Beck

Opis

The seeds of this conference were sown with the publication by Press, in 1965, of a paper in which he suggested that the displacement field due to a major earthquake may extend over much greater distances than had been thought possible before. Later on, Mansinha and Smylie pointed out that if Press was correct then, since the redistri bution of significant quantities of mass was involved, the inertia tensor of the earth would be altered and thus cause the earth to wobble; this revived the idea that earth quakes might be the long sought source for maintaining the Chandler Wobble. They argued that since earthquakes are sudden events it should be worthwhile trying to determine if there was any correlation between sudden changes in the Chandler term of the pole path and major earthquakes. Furthermore, since displacements occur both before and after an earthquake it might be possible to obtain a few days warning of a major earthquake by making instantaneous observations of the pole path. Analysis of the data indicated some correlation but, as often happens in science in general and in geophysics in particular, the results were not conclusive because of imperfect theory and the need for more accurate determinations of the pole position. It soon became clear that a meeting between geophysicists and astronomers involved in this type of work would be of mutual benefit."

Spis treści

Review.- Polar Wobble and Drift: A Brief History.- Elasticity Theory of Dislocation.- Earthquake Displacement Fields.- Deformation of a Spherical Earth Model by Finite Dislocations.- Present Day Measurement and Analysis of Rotation and Polar Motion.- Polar Motion in Recent Years.- Work of the Bureau International de l’Heure on the Rotation of the Earth.- Stability of Station and the Earth’s Figure.- Sudden Changes in Rotational Acceleration of the Earth and Secular Motion of the Pole.- Secular Motion of the Pole.- The Dynamical Coupling between Inner Core and Mantle of the Earth and the 24-year Libration of the Pole.- Deconvolution of the Pole Path.- Excitation of the Chandler Wobble.- Solar Activity and the Rotation of the Earth.- Seismic Excitation of the Chandler Wobble.- Core-Mantle Interactions: Geophysical and Astronomical Consequences.- An Examination of the Data Relating Pole Motion to Earthquakes.- Evidence for Association of Earthquakes with the Chandler Wobble, Using Long Term Polar Data of the ILS-IPMS.- An Investigation of PZT Observations for Evidence of the Existence of Polar Disturbances Due to Large Earthquakes.- A Re-Examination of Core-Mantle Coupling as the Cause of the Wobble.- A Possible Cause of the Correlation Between Earthquakes and Polar Motions.- Deformation Fields: Observation.- The Measurement of Small Earth Strains.- Some Earth Strain Measurements with Laser Interferometer.- Error Analysis of a Laser Strainmeter.- Spurious Local Effects Associated with Teleseismic Tilts and Strains.- Earthquake Predictions from Fault Movement and Strain Precursors in California.- Measurement of Movement on the San Andreas Fault.- Crustal Movement from Geodetic Measurements.- Geodetic Survey Measurements to Determine Motion in the Earth’s Crust.- Precise Measurement of the Earth’s Rotation and Polar Motion by New Methods.- The Role of Long Base-Line Interferometry in the Measurements of Earth’s Rotation.- Geophysical Applications of Long-Baseline Radio Interferometry.- Index of Names.- Index of Subjects.