The elastic energy of rotational and lunisolar tides and their role in the Earth's seismic activity

Abstract

An analytical expression for the elastic energy of the planet tidal deformations induced by external celestial bodies and by the rotational motion of the planet has been obtained. It was shown that the elastic energy is not the additive sum of the elastic energies of rotation and the corresponding planet–perturbing body pairs but contains additional terms of mutual character. Previously we have obtained a formula for the elastic energy of superposition of the lunisolar tides which also contains additional terms of mutual character caused by the mutual influence of the Moon and the Sun. In this paper we have obtained new mutual terms caused by the combination of the rotational deformations of the planet and by lunisolar tides. These additional terms are more significant and determine the main variations in the global tension state of the Earth. With various degrees of detail, we have looked at the variations in this energy in the last few decades, and also for a hundred years into the future. The peak excited conditions of the Earth and the condition of the active decrease in the elastic energy were determined on a timescale from 100 to 2100. The correlation of extreme variations in the elastic tidal energy of the Earth with large earthquakes has been studied.

Keywords:

• Rotational tide
• Lunisolar tides
• Superposition
• Elastic energy
• Earthquakes

Acknowledgements

Acknowledgements Barkin's work was funded by grant SAB2000-0235 from the Secretaria de Estado de Educacion y Universidades ) and by grant 02-05-64176 from the Russian Foundation for Basic Research. Partial support of the Spanish research projects AYA-2001-0787 and ESP2001-4533-PE is also acknowledged.