Subsurface voids pose significant geohazards, underscoring the need for their timely detection in order to mitigate the associated hazard. We report on a field study aimed at the comparative assessment of electrical resistivity tomography (ERT), seismic refraction tomography (SRT), and the multichannel analysis of surface waves (MASW) for void mapping in karstic regions. The field surveys were conducted at a site in central Texas, of typical karstic geomorphology, and involved the co-located deployment of ERT, SRT and MASW arrays. Post-surveying, boreholes were drilled at select locations for verification purposes. It is shown that MASW demonstrated limited ability to resolve voids due to its inherent theoretical limitations. In contrast, ERT revealed high-resistivity air-filled zones, and low-resistivity soil-filled regions, which aligned well with post-survey borehole logs, although deeper voids remained largely undetected. SRT clearly delineated voids through velocity reductions, but smoothing effects overestimated void velocities. Using ERT and SRT jointly provided improved void characterization compared to single-method-based interpretations, with ERT determining void type and SRT delineating boundaries. Despite the relative success of the joint ERT-SRT application, it is evident that without the corroboration provided by invasive testing, definitive void localization and characterization under arbitrary site conditions remains elusive.

中文翻译：

---

使用地球物理方法对不同尺寸和不同深度的地下空隙进行成像的比较研究


地下空隙会造成严重的地质灾害，因此需要及时检测以减轻相关危害。我们报告了一项实地研究，旨在比较评估电阻率层析成像 (ERT)、地震折射层析成像 (SRT) 和表面波多通道分析 (MASW)，以用于岩溶地区的空隙测绘。现场调查在德克萨斯州中部的一个具有典型喀斯特地貌的地点进行，并涉及 ERT、SRT 和 MASW 阵列的同地部署。勘测后，在选定位置钻孔以进行验证。结果表明，由于其固有的理论限制，MASW 解决空隙的能力有限。相比之下，ERT 显示了高电阻率空气填充区域和低电阻率土壤填充区域，这些区域与勘测后的钻孔测井吻合良好，但更深的空隙在很大程度上仍未被发现。 SRT 通过速度降低清晰地描绘了空隙，但平滑效果高估了空隙速度。与基于单一方法的解释相比，联合使用 ERT 和 SRT 可以提供改进的空洞表征，其中 ERT 确定空洞类型，SRT 描绘边界。尽管 ERT-SRT 联合应用相对成功，但很明显，如果没有侵入性测试提供的佐证，任意现场条件下的明确空隙定位和表征仍然难以捉摸。