Geophysical methods can characterize aquifer systems noninvasively and are particularly helpful to image the complex depositional architecture of the subsurface. Among these, ground-penetrating radar (GPR) is an effective tool for detailed investigations of shallow subsurface geometry, but it provides only limited information on hydraulic properties. Magnetic resonance tomography (MRT) provides parameters such as water content (porosity) and relaxation time/hydraulic conductivity, but it suffers from resolution limits. Furthermore, it requires knowledge of subsurface electrical resistivity, which can be obtained by electrical resistivity tomography (ERT) also suffering from resolution limits. To overcome the limitations in resolution, we have incorporated GPR reflectors as structural information into the ERT and MRT data inversion. We test the methodology on a synthetic example and find improved imaging properties compared to standard inversion, particularly at greater depths, where the resolution is limited. We apply the methodology to a test site that is characterized by a complex depositional architecture. The Quaternary deposits consist of interbedded meltwater deposits (aquifers) and till (aquitards), overlain by aeolian deposits. To image the subsurface depositional architecture in three dimensions, a $200\times 250\mathrm{m}$ area was surveyed by GPR. The use of GPR constraints clearly improves the resolution and zonation of the subsurface image, which is validated by drill-core analyses. We develop a workflow to combine GPR, MRT, and ERT, leading the way to high-resolution hydrogeologic models that can be used for groundwater studies.

中文翻译：

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探地雷达约束的磁共振层析成像技术，以改善水文地球物理特征

地球物理方法可以非侵入性地表征含水层系统，特别有助于成像地下复杂的沉积构造。在这些雷达中，探地雷达（GPR）是用于详细研究浅层地下几何形状的有效工具，但仅提供了有关水力特性的有限信息。磁共振层析成像（MRT）提供了诸如水含量（孔隙度）和弛豫时间/水导率等参数，但它受到分辨率限制的困扰。此外，它需要了解地下电阻率，这可以通过也受分辨率限制的电阻层析成像（ERT）获得。为了克服分辨率的限制，我们将GPR反射器作为结构信息合并到ERT和MRT数据反演中。我们在一个合成实例上测试了该方法，发现与标准反演相比，成像性能得到了改善，尤其是在分辨率有限的更大深度处。我们将该方法应用于以复杂沉积构造为特征的测试现场。第四纪沉积物由互层的融水沉积物（含水层）和耕作（阿奎塔德）组成，覆盖有风沙沉积物。要在三个维度上成像地下沉积构造，被风成矿床覆盖。要在三个维度上成像地下沉积构造，被风成矿床覆盖。要在三个维度上成像地下沉积构造，$200\times 250\mathrm{米}$区域由GPR调查。GPR约束的使用明显改善了地下图像的分辨率和分区，这已通过钻芯分析得到了验证。我们开发了结合GPR，MRT和ERT的工作流程，从而引领了可用于地下水研究的高分辨率水文地质模型。