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[1] This paper revisits the Arctic Ice Dynamics Joint Experiment (AIDJEX) assumptions about pack ice behavior with an eye to modeling sea ice dynamics. The AIDJEX assumptions were that (1) enough leads were present in a 100 km by 100 km region to make the ice isotropic on that scale; (2) the ice had no tensile strength; and (3) the ice behavior could be approximated by an isotropic yield surface. These assumptions were made during the development of the AIDJEX model in the 1970s, and are now found inadequate. The assumptions were made in part because of insufficient large-scale (10 km) deformation and stress data, and in part because of computer capability limitations. Upon reviewing deformation and stress data, it is clear that a model including deformation on discontinuities and an anisotropic failure surface with tension would better describe the behavior of pack ice. A model based on these assumptions is needed to represent the deformation and stress in pack ice on scales from 10 to 100 km, and would need to explicitly resolve discontinuities. Such a model would require a different class of metrics to validate discontinuities against observations.

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The circulation of hydrothermal fluid within upper oceanic crust constrains the global composition of seawater and is also responsible for many of the dynamic chemical and biological processes that alter the underlying volcanic rocks that form the sea floor. The heat of crustal formation drives this fluid circulation, and the impact on the overlying ocean is most easily observed at mid‐ocean ridge spreading centers. Previous efforts to quantify the heat associated with crustal formation have lacked information regarding the partitioning of thermal energy between discrete, high‐temperature vent fields, ubiquitous low‐temperature diffuse venting, and the pervasive conductive heat flux through the volcanic rocks.

Recent work has linked earthquake activity with changes in flow and temperature due to hydrothermal venting at mid‐ocean ridges. These intriguing relationships are important motivation for modeling marine hydrothermal systems. However, a re‐examination of some earlier vent monitoring data from the Juan de Fuca Ridge, combined with analysis of recently reprocessed SOSUS (SOund Surveillance System) hydrophone data (Figure 1), suggest that such activity may be linked over considerable distances of greater than 200 km and reaction intervals of over a month. The available observational data are sparse, so the direct association between earthquakes and changes in crustal fluid circulation are difficult to verify. However, the response times and distance scales are consistent with other observations, including earthquakes in land‐based settings [Hill et al., 1993] and modeling of flow in porous media [Pruis et al., 2000]. If true, these associations imply that marine hydrothermal systems are extremely complex and may be sensitive to very subtle environmental changes.