Bulletin géodésique

, Volume 88, Issue 1, pp 151–157 | Cite as

The use of a laser extensometer to observe strain in a large ground sample

  • V. Vali
  • R. C. Bostrom


The design and construction are described of an experimental strainmeter. This observes changes in the number of waves of light standing in a one-kilometer gap between points on the earth’s surface. Strain is observed over a frequency range of zero to several hundred hertz, to an accuracy of an arbitrarily-small fraction of a wave-length of light. Frequency-dependent phase and amplitude distortion are absent. As the read-out is of the nature of a servo device, dynamic range limitations are not encountered.

The prototype instrument is located in a region affected by the world rift system.


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Copyright information

© Bureau Central de L’Association Internationale de Géodésie 1968

Authors and Affiliations

  • V. Vali
    • 1
    • 2
  • R. C. Bostrom
    • 1
    • 2
  1. 1.Boeing Scientific Research LaboratoriesSeattle
  2. 2.University of WashingtonSeattle

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