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Surface Wave Propagation in the Western United States


Alexander, Shelton Setzer (1963) Surface Wave Propagation in the Western United States. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/GDQP-PB52.


Part I

Multi-mode group velocity dispersion of both Rayleigh and Love waves was measured for a number of paths in the Western United States by means of a technique developed for separating the modes. Results for each region studied are interpreted in terms of a crustal structure which produces simultaneous agreement with all the modes observed, as well as available body wave data. Certain diagnostic features of group velocity dispersion curves were noted and used to advantage in this study.

The analysis techniques developed have rather broad geophysical applications, for example in studies of source properties, interference phenomena, and noise properties.

Part II

The effects of the transition zone at the continental margin of Southern California on Rayleigh wave propagation have been investigated. Among the anomalous effects discovered are a minimum in phase velocity between 20 and 35 seconds period, different phase velocities on reversed paths across the same array, and systematic lateral re-fraction at the continental boundary. These anomalous effects can be attributed largely to the slope and curvature of the Mohorovičić discontinuity across this region. An ultrasonic model was constructed to aid in interpreting these results.

Interpretation of the dispersion for periods below 20 seconds indicates that the crust thickens toward the continent with a slope of about 5° attaining a thickness of approximately 35 km under Southern California.

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):
  • Press, Frank
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1963
Additional Information:Title varies in the 1963 Caltech commencement program: Surface Wave Propagation in the Western United States: I. Crustal Structure in the Western United States from Multimode Surface Wave Dispersion. II. The Effects of the Continental Margin in Southern California on Rayleigh Wave Propagation
Record Number:CaltechTHESIS:05162012-110631966
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7036
Deposited By: Tony Diaz
Deposited On:17 May 2012 18:56
Last Modified:05 Jan 2024 00:29

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