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Body-Wave and Earthquake Source Studies


Teng, Ta-Liang (1966) Body-Wave and Earthquake Source Studies. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9VPH-AN84.


The present work concerns a study on the radiation and propagation of seismic body waves. Based on a reformulated seismic ray theory and supplemented by the results of several associated boundary value problems, a method of body wave equalization is described which enables the extrapolation of body-wave fields from one point to another.

Applications of the above method to studies of earthquake source mechanism and earth's structure, specifically its anelasticity, are presented. The findings for two deep-focus earthquakes can be summarized by: (1) a displacement dislocation source, or an equivalent double couple, can generally explain the observed radiation fields, (2) the source time functions can be explained by a build-up step (1 - e -t/τ)H(t), and τ appears to be longer for larger earthquakes, (3) the total energy calculated from equalized spectrums is: for the Banda Sea earthquake (M = 6-1/4 - 6-3/4), E = 1.01x1022 ergs; and for the Brazil earthquake (M = 6-3/4 - 7), E = 2.56x1023 ergs.

From the spectral ratios pP/P and P/P, it is found (1) that the upper 430 km of the mantle has an average Qɑ = 105, (2) that Qɑ increases very slowly until depth of about 1000 km, and (3) that Qɑ rises rapidly beyond a depth of 1000 km, remains a high value in the lower mantle and drops sharply toward the core-mantle boundary.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Geophysics and Applied Mathematics)
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Minor Option:Applied Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Anderson, Donald L. (advisor)
  • Press, Frank (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:28 April 1966
Funding AgencyGrant Number
Advanced Research Projects AgencyUNSPECIFIED
Air Force Office of Scientific ResearchAF-49(638)-1337
Record Number:CaltechTHESIS:09282017-160405428
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10467
Deposited By: Benjamin Perez
Deposited On:29 Sep 2017 14:34
Last Modified:08 Mar 2024 20:04

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