ABSTRACT In this research, we have studied the capabilities and limitations of the transient electromagnetic sounding applied to investigate the structure and composition of the moraine deposits covering a crystalline basement. It has been experimentally demonstrated that using the ungrounded antennas one can not only determine the electrical resistivity of different layers in the alluvium deposits and map the surface topography of the crystalline basement down to a depth of 70–100 m, but can also minimize the costs and the damage done to the environment. Additionally, transient electromagnetics helps to reveal the layers within the moraine strata that often have different resistivities and depths. The use of single antennas of size 12 m × 12 m–25 m × 25 m for field excitation and registration of transient responses allows for maximum localization of the targets and provides a high horizontal resolution in strongly heterogeneous media. The limitations of the method due to the induced polarization effect have also been investigated. Overall, despite some limitations, the transient electromagnetic method appears to be effective in the mapping, assessment and analysis of hazards in landslide‐prone areas, prior to geotechnical soundings in wells.

中文翻译：

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通过瞬态电磁测深绘制基岩地形和冰碛沉积物：挪威奥斯陆地堑

摘要 在这项研究中，我们研究了瞬态电磁探测的能力和局限性，用于研究覆盖结晶基底的冰碛沉积物的结构和组成。实验证明，使用不接地天线不仅可以确定冲积层中不同层的电阻率并绘制下至 70-100 m 深度的结晶基底的表面形貌，而且还可以最大限度地降低成本以及对环境造成的破坏。此外，瞬态电磁学有助于揭示冰碛地层内通常具有不同电阻率和深度的层。使用大小为 12 m × 12 m–25 m × 25 m 的单个天线进行场激励和瞬态响应注册，可以最大限度地定位目标，并在强异构介质中提供高水平分辨率。还研究了由于诱导极化效应导致的方法的局限性。总体而言，尽管存在一些局限性，但瞬态电磁法似乎在对井中岩土工程探测之前的滑坡易发地区的灾害进行测绘、评估和分析方面是有效的。