Abstract The development of shallow landslides is strongly connected to the changes in the water content of soils on hillslopes, their clay content and permeability distribution, which, in turn, are playing an important role regarding their hydro-mechanical properties. A non-intrusive geophysical method able to map these properties would be very helpful. The most common geoelectrical method, DC (Direct Current) resistivity, cannot be used as a stand-alone technique for this purpose since it depends on two contributions (bulk and surface conductivities), which depend on the water content and the cation exchange capacity (CEC) of the material. Induced polarization is a geophysical method that can be now used to complement DC resistivity in providing key material properties that can be used to diagnose potential risks for failure. We first recall the basic principles behind the induced polarization method from laboratory to field scales and key findings in the underlying petrophysics needed to jointly interpret electrical conductivity and normalized chargeability tomograms. Then, we apply these relationships to a field survey carried out over a shallow landslide at Claix (Isere, France), close to Grenoble. A 3D induced polarization survey was carried out and interpreted in terms of the clay content, water content, and permeability distributions. We demonstrate that the landslide is associated with a channel of high water content corresponding with the presence of travertine, a flow-path, and a permeability barrier downslope corresponding to the presence of plastic clays. This study demonstrates that induced polarization can be used to characterize the impacted volume and therefore might have been useful to map the area before the landslide to assess the possible risk of failure. This methodology could play a key role in mitigation planning.

中文翻译：

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感应极化作为表征浅层滑坡的工具

摘要 浅层滑坡的发育与山坡土壤含水量、粘土含量和渗透率分布的变化密切相关，而这些变化又对其水力学特性起着重要作用。能够绘制这些属性的非侵入式地球物理方法将非常有帮助。最常见的地电方法 DC（直流）电阻率不能用作此目的的独立技术，因为它取决于两个贡献（体电导率和表面电导率），这取决于水含量和阳离子交换容量（ CEC) 的材料。感应极化是一种地球物理方法，现在可用于补充直流电阻率，以提供可用于诊断潜在故障风险的关键材料特性。我们首先回顾一下从实验室到现场尺度的诱导极化方法背后的基本原理，以及共同解释电导率和归一化带电断层图所需的基础岩石物理学中的关键发现。然后，我们将这些关系应用于在靠近格勒诺布尔的 Claix（法国伊泽尔）浅层滑坡上进行的实地调查。进行了 3D 激发极化调查，并根据粘土含量、水含量和渗透率分布进行了解释。我们证明，滑坡与高含水量的通道有关，对应于石灰华的存在，流动路径和渗透性屏障下坡，对应于塑性粘土的存在。这项研究表明，诱发极化可用于表征受影响的体积，因此可能有助于绘制滑坡前的区域地图，以评估可能的故障风险。这种方法可以在缓解规划中发挥关键作用。