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

将采用岩石力学中目前用于测量粘弹性/塑性材料中的原地应力的方法，开发一种直接、原地测量深层冰川冰中应力张量的技术。 直接应力和变形测量将结合起来。 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。 这将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。 冰川冰和冰川床之间的耦合的空间和时间特性的确定是必要的了解目前感兴趣的几乎所有的冰块的动态。 基底和边缘牵引力的变化是极地冰流、崩解和冰川涌动的关键控制因素。冰盖的行为，以及从冰盖取芯的地层解释，取决于在床上的耦合模式和速度场，在冰中出现的结果的理解。

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.