The belowground architecture of the critical zone (CZ) consists of soil and rock in various stages of weathering and wetness that acts as a medium for biological growth, mediates chemical reactions, and controls partitioning of hydrologic fluxes. Hydrogeophysical imaging provides unique insights into the geometries and properties of earth materials that are present in the CZ and beyond the reach of direct observation beside sparse wellbores. An improved understanding of CZ architecture can be achieved by leveraging the geophysical measurements of the subsurface. Creating categorical models of the CZ is valuable for driving hydrologic models and comparing belowground architectures between different sites to interpret weathering processes. The CZ architecture is revealed through a novel comparison of hillslopes by applying facies classification in the elastic-electric domain driven by surface-based hydrogeophysical measurements. Three pairs of hillslopes grouped according to common geologic substrates — granite, volcanic extrusive, and glacially altered — are classified by five different hydrofacies classes to reveal the relative wetness and weathering states. The hydrofacies classifications are robust to the choice of initial mean values used in the classification and noncontemporaneous timing of geophysical data acquisition. These results will lead to improved interdisciplinary models of CZ processes at various scales and to an increased ability to predict the hydrologic timing and partitioning. Beyond the hillslope scale, this enhanced capability to compare CZ architecture can also be exploited at the catchment scale with implications for improved understanding of the link between rock weathering, hydrochemical fluxes, and landscape morphology.

中文翻译：

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不同地质基底的山坡临界带结构的水文地球物理比较

临界区 (CZ) 的地下结构由处于不同风化和潮湿阶段的土壤和岩石组成，它们充当生物生长的介质、调节化学反应并控制水文通量的分配。水文地球物理成像为 CZ 中存在的地球材料的几何形状和特性提供了独特的见解，除了稀疏的井筒之外，这些材料超出了直接观察范围。通过利用地下的地球物理测量，可以更好地了解 CZ 结构。创建 CZ 的分类模型对于驱动水文模型和比较不同站点之间的地下结构以解释风化过程很有价值。通过在基于地表的水文地球物理测量驱动的弹性电域中应用相分类，通过山坡的新颖比较，揭示了 CZ 结构。三对山坡根据常见的地质基质（花岗岩、火山喷出物和冰川蚀变）按五种不同的水相分类，以揭示相对湿度和风化状态。水相分类对于地球物理数据采集的分类和非同期时间中使用的初始平均值的选择是稳健的。这些结果将导致在不同尺度上改进 CZ 过程的跨学科模型，并提高预测水文时间和分区的能力。超越山坡规模，