Creep Measurements in Igneous Rocks with Some Applications to Aftershock Theory

Citation

Lomnitz, Cinna (1955) Creep Measurements in Igneous Rocks with Some Applications to Aftershock Theory. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/A2KE-9Y60. https://resolver.caltech.edu/CaltechETD:etd-01082004-111506

Abstract

First Part.

Cylindrical specimens of Southern California granodiorite and gabbro were creep-tested at constant torques in a high-magnification torsion apparatus. Complete creep and creep recovery curves at room temperature were recorded for periods of about 10,000 minutes.

The results are represented by an empirical equation of the form: s = p (a+b log t) where s is the strain, p the stress and t the time. No evidence was found of creep behavior suggestive of the Michelson equation.

For some granodiorite samples the viscosity was of the order of 3 x 10¹⁵ poises. The behavior of the rocks under prevailing test conditions was not appreciably different from that of other polycrystalline materials.

Second Part.

A quantitative treatment of the Benioff aftershock sequences on the basis of the theory of viscoelasticity is given. The minimum coefficient of viscosity found by this method is of the order of 10[superscript 19] poises, in good agreement with accepted viscosity values for the earth's crust.

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