Investigation of Polar Snow Using Seismic Velocity Gradients
Compressional wave velocity gradients at 43 of 50 Antarctic traverse stations plot as sequences of straight lines on semilogarithmic graph paper. Intersections of the lines appear to correlate with depths at which the predominant metamorphic mechanism in polar snow changes. The seismie pattern suppo...
| Published in: | Journal of Glaciology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
1975
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s002214300001337x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214300001337X |
| Summary: | Compressional wave velocity gradients at 43 of 50 Antarctic traverse stations plot as sequences of straight lines on semilogarithmic graph paper. Intersections of the lines appear to correlate with depths at which the predominant metamorphic mechanism in polar snow changes. The seismie pattern supports a three-layer interpretation of snow densification. The base of the upper layer (8.4±12.3 m) corresponds to the “critical depth” of Anderson and Benson (1963) at which snow grains settle into a “random closepacked” arrangement. The base of the lower layer may correspond to the firn: ice transition depth, but more data are needed to confirm this conclusion. It is unclear what densification phenomenon is marked by the base of the middle layer (27.7±4.4 m). The distinction between the middle and lower layers tends to disappear and the velocity gradient at a fixed depth increases as mean annual accumulation decreases. |
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