Showing papers on "Accumulation zone published in 1984"
TL;DR: In this article, temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas, which is similar to the thermal structure found in a subarctic surge glacier.
Abstract: Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area th...
259 citations
TL;DR: In this paper, it has been shown that the damping due to the intracrustal asthenosphere can explain the observed narrow zone of cyclic strain accumulation and release.
Abstract: Strain accumulation measurements adjacent to the San Andreas fault have indicated that the strain accumulation zone extends only a few tens of kms away from the fault. While the restricted zone of cyclic accumulation and release of elastic energy adjacent to major strike-slip faults has been attributed to a viscoelastic asthenosphere's damping effect, the narrowness of the San Andreas zone implies a thickness of the lithosphere that, at 10-20 km, may not be consistent with the relatively low surface heat flow measurements obtained. It is presently proposed that an upper elastic plate extends to a depth of 15 km, and that beneath this upper elastic plate is a soft, intracrustal asthenosphere exhibiting a viscoelastic behavior. A second elastic layer lies under this, followed by the asthenosphere. It is shown that the damping due to the intracrustal asthenosphere can explain the observed narrow zone of cyclic strain accumulation and release.
54 citations
TL;DR: In this article, steady-state solutions are used to check and complete data sets, before using models of greater complexity to calculate temperature fields in a more realistic way Test runs with a computer model, which allows for true two-dimensional solutions and realistic velocity fields, are described for two examples from the Swiss Alps, which illustrate, in a semi-quantitative way, that advection of cold ice by glacier flow strongly influences the temperature distribution in both an existing large valley glacier with a cold accumulation zone (Grenzgletscher), and a large piedmont glacier
Abstract: Modelling temperature distribution in non-temperate mountain glaciers presents problems not normally encountered when modelling ice sheets or ice shelves These problems are mainly concerned with numerical instabilities caused by the high, nonuniform gradients of various input parameters (geometry, mass balance, surface temperature, and flow velocity) Steady-state solutions must be used to check and complete data sets, before using models of greater complexity to calculate temperature fields in a more realistic way Test runs with a computer model, which allows for true two-dimensional solutions and realistic velocity fields, are described for two examples from the Swiss Alps These steady-state calculations illustrate, in a semi-quantitative way, that advection of cold ice by glacier flow strongly influences the temperature distribution in both an existing large valley glacier with a cold accumulation zone (Grenzgletscher), and a large piedmont glacier of the last ice age, around 18 ka BP (Rheingletscher) Non-steady-state models are being prepared and tested for future calculations
26 citations
TL;DR: In this article, a surge of Hazard Glacier, believed to have started in 1981, displaced ice as much as 0.7 km, and the authors attributed these anomalies to various effects of past surges and to ablation at the upper surface.
Abstract: A surge of Hazard Glacier, believed to have started in 1981, displaced ice as much as 0.7 km. Before the surge, ice thickness was measured by radio echo sounding and temperatures were taken in three holes to the glacier bed. The glacier is subpolar with 10 m temperatures near −5.4 °C, and temperature versus depth profiles show many anomalous features. We attribute these anomalies to various effects of past surges and to ablation at the upper surface. The interpretations are supported by simple calculations derived from dimensional analysis. Part of the glacier is warm based: at two sites the basal temperature was at the melting point; at the third site, upstream from the others, it was −2.70 °C.
8 citations