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

采用岩石力学中目前用于测量粘弹/塑性材料中的地应力的方法，将开发一种直接、原位测量深冰川中应力张量的技术。直接应力和变形测量将结合在一起。这将在经历相当复杂的滑动行为的冰川河床附近提供两个关键特性。首次对冰川冰中的全应力张量和全应变率张量进行了独立观测。确定冰川冰和冰床之间耦合的空间和时间特征对于了解几乎所有当前感兴趣的冰块的动力学是必要的。基面和边缘牵引力的变化是极地冰川、崩解和涌动的冰川的关键控制因素。冰盖的行为以及对取自冰盖的岩芯的地层学解释，取决于对冰床耦合模式和由此在冰中产生的速度场的理解。

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.