Nonlinear Stress Propagation in the Earth's Upper Mantle
نویسنده
چکیده
This paper consists of two parts. The first is theoretical and extends Elsasser's theory of stress propagation in the upper mantle to an asthenosphere with nonlinear heology. Exact solutions of the nonlinear equations are found for two geologically important problems. The second part uses these theoretical results as the basis for a measurement of the rheology of the asthenosphere. The seaward migration pattern of aftershocks from the February 4, 1965, Rat Island earthquake is analyzed, and strong evidence for a nonoNewtonian stress-strain relation in the asthenosphere is presented. It is found that an individual arge earthquake can influence the regional stress pattern only to a distance of about 300 km perpendicular to the line of rupture. Excellent agreement isfound between the stress propagation coefficient calculated from the aftershock migration pattern and that calculated from laboratory measurements of high-temperature creep in olivine. We thus arrive at a picture of stress propagation in the upper mantle which is consistent both with theoretical expectation and with observational evidence.
منابع مشابه
Theoretical Equations of State
Monogr. 13, edited by P. J. Hart, pp. 225-230, AGU, Washington, D.C., 1969. Talwani, M., and X. Le Pichon, Gravity field over the Atlantic Ocean, in The Earth's Crust and Upper Mantle, Geophys. Monogr. 13, edited by P. J. Hart, pp. 341-351, AGU, Washington, D.C., 1969. Tarr, A. C., New maps of polar seismicity, Bull. Seismol. Soc. Amer., 60, 1745-1747,1970. Toksoz, M. N., M. A. Chinnery, and D....
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