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Recording Wire Strainmeters on the Barnes Ice Cap, Baffin Island, Canada

  • K. Evans (a1), D.J. Goodman (a2) and G. Holdsworth (a3)

Abstract

The report describes an experiment to evaluate the use of geophysical (Cambridge-type) wire strainmeters for the rapid acquisition of strain-rate data and to compare strains on a large ice mass over gauge distances of 5 m, 50 m, and 1 km.

Three continuously recording wire strainmeters were installed at the centre of two separate arrays of strain poles 10.6 km and 19.5 km from the ice divide on the Barnes Ice Cap. Data was collected between 24 April and 15 May 1976. The 1 km strain arrays had previously been measured in 1974 and 1975. The results show good agreement between the strainmeter data and the larger strain arrays at the 10.6 km site but differ at the 19.5 km site. When the daily means are calculated for the strainmeters at the 19.5 km site, the strain-rates show a possible periodic variation with an apparent period ofabout 11 d. Since there appears to be no direct correlation between the strainmeter signal and either temperature or pressure, the result is assumed to represent real varying strain within the ice.

Résumé

Le rapport décrit une expérimentation conduite pour estimer l'utilité des capteurs de contrainte géophysique à câble (type Cambridge) pour acquérir rapidement des données sur le régime des contraintes et pour les comparer sur un vaste amas glaciaire avec des distances de jauges de 5 m, 50 m et 1 km.

Trois capteurs de contrainte à câble à enregistrement continu furent installés au centre de deux dispositifs séparés de mesures de tension situés à 10,6 km et 19,5 km de la division de la glace sur le Barnes Ice Cap. Les résultats furent recueillis entre les 24 avril et 15 mai 1976'. Le dispositif de 1 km avait déjà été mesuré en 1974 et 1975. Les résultats montrent une bonne concordance entre les capteurs à câble et le dispositif plus vaste de mesure sur le site à 10,6 km, mais des divergences sur le site à 19,5 km. Quand on calcule les moyennes journalières pour les capteurs sur le site à 19,5 km, le régime des contraintes montre une possible variation périodique avec une période apparente d'environ 11 jours. Comme il ne semble pas y avoir de corrélation directe entre le signal de capteur de contrainte et soit la température, soit la pression, on pense que le résultat représente bien une variation réelle de la contrainte dans la glace.

Zusammenfassung

Der Bericht sehildert eincn Versuch zur Auswertung des Einsatzes von geophysikalischen Draht-Dehnungsmessern (Cambridge-Typ) fur die schnelle Gewinnung von Werten der Dehnungsgeschwindigkeit und fur den Vergleich von Dehnungen einer grossen Eismasse uber Messtrecken von 5 m, 50 m und 1 km.

Drei fortlaufend registrierende Draht-Dehnungsmesser wurden im Zentrum zweier getrennter Système von Dehnungspegeln aufgestellt, die 10.6 km und 10.5km von der Eisscheide des Barnes Ice Cap entfernt lagen. Der Messzeitraum erstreckte sich vom 24. April bis zum 15. Mai 1976. Die Dchnungsmessungen iiber 1 km waren schon in den. Jahren 1974 und 1975 vorgenommen worden. Die Werte der Dehnungsmesser und die Messungen uber grossere Distanz stimmen beim 10.6 km-System gut uberein, differieren jedoch beim 19,5 km-System. Berechnet man die Tagcsmittel fur die Dehnungsmesser im 19,5 km-System, so zeigen die Dehnungsgeschwindigkeiten cine moglicherweise periodische Schwankung, wobei sich die Période mit etwa 11 Tagen ergibt. Da keine direkte Korrelation zwischen den Dehnungsmesserdaten und der Temperatur oder dem Druck zu bestchen scheint, konnen die Ergebnisse als tatsachliche Schwankungen der Spannung angesehen werden.

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Copyright

References

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Classen, D. F., 1977, Temperature profiles for the Barnes Ice Cap surge zone. Journal of Glaciology, Vol. 18 No. 80, p. 39-405.
Colbeck, S. C, and Evans, R. J. 1971. Small-scale strain measurements on a glacier surface. Journal of Glaciology, Vol. 10, No. 59, p. 23743.
Goodman, D. J. Unpublished. Creep and fracture of ice and surface strain measurements on glaciers and sea ice. [Ph. D. thesis, University of Cambridge, 1977.]
Goodman, D. J., and others. 1975. Wire strainmeters on ice, [by] Goodman, D. J., Allan, A. J., Bilham, R. G.. Nature, Vol. 255, No. 5503, p. 4546.
Holdsworth, G. 1973. Evidence of a surge on Barnes Ice Cap, Baffin Island. Canadian Journal of Earth Sciences, Vol. 10, No. 10, p. 1565—74.
Holdsworth, G. 1975. Measurement of small strain-rates over short time periods. Journal of Glaciology, Vol. 15, No. 71, p. 31724.
Jaeger, J. C. 1962. Elasticity, fracture and flow. London, Methuen and Co., Ltd.
Meier, M. F., and others. 1957. Preliminary study of crevasse formation, Blue Ice valley, Greenland, 1955, by Meier, M. F. [and 5 others]. U.S. Snow, Ice and Permafrost Research Establishment. Report 38.
Nye, J. F. 1959. A method of determining the strain-rate tensor at the surface of a glacier. Journal of Glaciology, Vol. 3, No. 25, p. 40917.
Sanderson, T. J. O. 1978. Thermal stresses near the surface of a glacier. Journal of Glaciology, Vol. 20, No. 83, p. 25783.
Warner, G., and Cloud, G. 1974. Measurement of surface strain rates in glaciers using embedded wire strain gauges. (In Rossi, B. E., ed. Proceedings of the third International Congress on Experimental Mechanics, Los Angeles, California, May 13th 18th, 1973. Westport, Conn., Society for Experimental Stress Analysis, p. 2428.).
Zumberge, J. H., and others, 1960. Deformation of the Ross Ice Shelf near the Bay of Whales, Antarctica, by Zumberge, J. H., Giovinetto, M. G.. Kehle, R. and Reid, J.. IGT Glaciological Report Series (New York), No. 3.

Recording Wire Strainmeters on the Barnes Ice Cap, Baffin Island, Canada

  • K. Evans (a1), D.J. Goodman (a2) and G. Holdsworth (a3)

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