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Earthquakes in the Walker Pass Region, California, and their Relation to the Tectonics of the Southern Sierra Nevada


Gardner, John Kelsey (1964) Earthquakes in the Walker Pass Region, California, and their Relation to the Tectonics of the Southern Sierra Nevada. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/R906-T104.


The locations and depths of earthquakes occurring in the Walker Pass Region, California, and the surrounding area have been examined for the period from January, 1934, to December, 1963. Whenever possible, least-square computer locations programs have been used to check or revise the previously determined epicenters and origin times. In most cases, epicenters determined by machine methods are within ten kilometers of those previously assigned. Accurate depths, whenever they could be calculated, were always found to be less than fifteen kilometers and usually less than ten kilometers.

The sequence of earthquakes occurring in the Walker Pass region in March, 1946, has been carefully examined. While no major shifts in epicenters were found, the depth of the main shock of this series has been revised from twenty-one kilometers to less than ten kilometers. This revision cast doubt on the assertion that the earthquake originated on the Sierra Front Fault and made it likely that the earthquake occurred on one of the northwest-southeast trending faults in the interior of the Sierra mass.

Finally, the general distribution of earthquakes furnishes no evidence for the existence of a continuous deep-lying structure traversing the southern part of the Sierra Nevada. While the possibility of the existence of such a structure has not been excluded, practically all of the evidence upon which such a speculation might be based has been removed. Any relation between activity in this region and the activity in the nearby White Wolf Fault region must instead be explained by means of a mutual transfer of strain between systems of different trend and character.

The computer programs used for the location of the earthquakes reported in this study are discussed in Appendices A and B.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Geophysics)
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Richter, Charles F.
Thesis Committee:
  • Unknown, Unknown
Defense Date:29 May 1964
Record Number:CaltechETD:etd-10152002-100918
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4092
Deposited By: Imported from ETD-db
Deposited On:16 Oct 2002
Last Modified:19 Jan 2024 18:42

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