Fused-quartz extensometer for secular, tidal, and seismic strains
- Creators
- Benioff, Hugo
Abstract
A description is given of two fused-quartz extensometers located in mountain tunnels at Dalton Canyon and Isabella in Southern California and designed for observing long-period seismic-wave strains, earth tidal strains, and secular strains. They consist essentially of instruments for measuring and recording variations in the separation of two piers by comparison with a length standard of fused-quartz tubing. The sensitivity for secular strains, denned as the least detectable strain increment, is approximately 10^(−7). For tidal and seismic-wave strains, the sensitivity is higher—a 1-mm deflection of the recorder represents a strain increment of 5.2 × 10^(−10). In both cases the maximum usable sensitivity is limited by ground-strain unrest or noise, generated by wind, barometric-pressure variations, temperature variations of the surface layers of the ground, and variations in ground-water saturation.
Additional Information
Copyright © 1959, The Geological Society of America, Inc. Received August 18, 1958.Additional details
- Eprint ID
- 48145
- DOI
- 10.1130/0016-7606(1959)70[1019:FEFSTA]2.0.CO;2
- Resolver ID
- CaltechAUTHORS:20140806-154620758
- Created
-
2014-08-06Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological Sciences
- Other Numbering System Identifier
- 898