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Accession number;01A0565387
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| Title;Modernizing the Finnish Long Water-Tube Tiltmeter. |
| Author;
RUOSTALAINEN H
(Finnish Geodetic Inst., Masala, Fin)
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Journal Title;Journal of the Geodetic Society of Japan
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Journal Code:G0199A
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ISSN:0038-0830
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VOL.47;NO.1;PAGE.28-33(2001)
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| Figure&Table&Reference; |
| Pub. Country;Japan |
| Language;English |
| Abstract;The very long water-tube tiltmeter of the Finnish Geodetic Institute is to be modernized with new materials and a new recording system. We shall keep the stable interferometer arm design as it is, following concepts developed earlier at the Finnish Geodetic Institute. The new interferometric recording system will consist of a HeNe laser, fibre optics and a digital PC-camera. The automated interpretation of interference fringes by computer is currently been tested in the laboratory. The pot/interferometer system will be mounted on an adjustable tripod. The pot and the tube are to be built of glass. Special attention is to be paid to matching the tube/fluid thermal expansion and to eliminating corrosion. Slow minute corrosion in the instrument is difficult to detect and therefore the choice of correct material is vital under hostile underground conditions. An optical fluid with appropriate physical properties and compatible with glass would be preferable to water. By using a higher interferometric resolution we shall try to shorten the instrument without losing the high nanoradian tilt resolution and good long-term instrumental stability. A modular design will make it easy to install the tiltmeter in various environments, for different applications in geodynamics. (author abst.) |
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