3D and Boundary Effects on 2D Electrical Resistivity Tomography
3D and Boundary Effects on 2D Electrical Resistivity Tomography
复制标题
2D 电阻率层析成像的 3D 和边界效应
作者：
Yin;Chih‐Ping Lin;Chin;Ko
电阻率层析成像（ERT）是地质、水文地质和地质环境调查中应用最广泛的地球物理方法之一。虽然3D ERT现在已经可用，但2D ERT仍然是最先进的，因为它在现场工作中简单，空间要求低。二维ERT假设地面条件垂直于测量线，测量线外均匀。在地质走向不垂直于测量线、地形变化或测量线附近埋有物体等情况下，这种假设往往会被违背。由于违反二维假设，二维电阻率层析图中可能出现的误差或伪影往往被忽视。本文旨在数值研究不同简化条件下二维ERT的边界效应。参数化研究考虑了电阻率对比、埋设物的深度和尺寸以及电极间距等潜在因素。结果表明，离线地质特征可能在一定程度上投影到二维层析图上，这取决于上述因素。边界效应的机制和意义可以从这些参数研究中得出。
Electrical resistivity tomography (ERT) is one of the most widely used geophysical methods in geological, hydrogeological, and geo-environmental investigations. Although 3D ERT is now available, 2D ERT remains state-of-the-practice due to its simplicity in fieldwork and lower space requirements. 2D ERT assumes that the ground condition is perpendicular to the survey line and outside the survey line is homogeneous. This assumption can often be violated in conditions such as geologic strikes not perpendicular to the survey line and topographic changes or buried objects near the survey line. Possible errors or artifacts in the 2D resistivity tomogram arising from violating the 2D assumption are often overlooked. This study aimed to numerically investigate the boundary effects on 2D ERT under various simplified conditions. Potential factors including resistivity contrast, depth and size of buried objects, and electrode spacing were considered for the parametric studies. The results revealed that offline geologic features may project onto the 2D tomogram to some extent, depending on the aforementioned factors. The mechanism and implications of boundary effects can be drawn from these parametric studies.