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Relaxation Phenomena and the Origin of Earthquakes


Lieber, Paul (1951) Relaxation Phenomena and the Origin of Earthquakes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/S59Y-Q172.


In this thesis an attempt is made to demonstrate in accordance with known physical principles that significant changes in the macroscopic equilibrium of the earth can be attributed to rate processes which do not call upon the existence of macroscopic gradients and disturbances in the earth. Such processes and their relation to known mechanisms of plastic deformation and to the experimentally established behavior of materials under high pressures are critically evaluated. This evaluation is carried out in the light of some well-established concepts of statistical mechanics and modern physics. In so doing specific methods for producing seismic disturbances which are based upon known mechanisms of plastic deformation and rupture become indicated. It is also shown that under very high pressures, pressure and temperature can complement each other in producing disturbances associated with polymorphic transitions of materials leading to a reduction in symmetry of their lattice structure.

A specific mechanism for producing and repeating earth­quakes at shallow and intermediate depths is proposed. This mechanism is based upon the existence of a visco-elastic surface layer supported by a plastic material embodied with stress relaxing properties.

The effect of such a configuration upon the propagation of Love Waves is investigated quantitatively. This investigation shows that the plastic sub-layer would explain the observed selection of the period of Love Waves.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Geophysics and Mathematics)
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Minor Option:Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gutenberg, Beno (advisor)
  • Michal, Aristotle D. (co-advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1951
Additional Information:Title varies slightly in 1951 Caltech Commencement program: On Relaxation Phenomena and the Origin of Earthquakes.
Record Number:CaltechTHESIS:10132017-094352043
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10514
Deposited By: Benjamin Perez
Deposited On:13 Oct 2017 18:20
Last Modified:03 May 2023 21:22

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