Collaborative Research: Direct Measurement of the In-situ Stress Tensor at Depth in Glacier Ice

通过采用目前岩石力学中用于测量粘弹性/塑性材料中原位应力的方法，将开发一种直接原位测量深层冰川冰中应力张量的技术。 将结合直接应力和变形测量。 这将在经历相当复杂滑动行为的冰川床附近提供两个关键特性。 首次获得冰川冰中全应力张量和全应变率张量的独立观测结果。 确定冰川冰与冰川床之间耦合的空间和时间特征对于理解当前感兴趣的几乎所有冰块的动力学是必要的。 基础牵引力和边缘牵引力的变化是极地冰流、冰川崩解和涌动的关键控制因素。冰盖的行为以及对冰盖核心的地层解释取决于对冰床耦合模式以及因此在冰中出现的速度场的理解。

A technique for direct, in-situ measurement of the stress tensor in deep glacier ice will be developed by adapting methods presently in use in rock mechanics for the measurement of in-situ stress in visco-elastic/plastic materials. Direct stress and deformation measurements will be combined. This will provide two critical properties near the bed of a glacier experiencing fairly complex sliding behavior. For the first time, independent observations of the full stress tensor and the full strain rate tensor in glacier ice will be obtained. The determination of the spatial and temporal character of coupling between glacier ice and the glacier bed is necessary for understanding the dynamics of virtually all ice masses of current interest. Variations in basal and marginal tractions are critical controlling factors in polar ice streams, calving and surging glaciers. The behavior of ice sheets, as well as the stratigraphic interpretation of cores taken from ice sheets, depend on an understanding of the patterns of coupling at the bed and the velocity fields that arise in the ice as a consequence.