On El Hierro (Canary Islands, Spain), the company Gorona del Viento El Hierro S.A. carried out the construction of a Wind‐Pumped Hydro Power Station in order to achieve the energy autonomy on the island through 100% renewable energy. The station consists of two man‐made water reservoirs, whose design was adapted to the island topography and emplaced in a valley and an inactive crater. In order to study the subsurface of both reservoirs, the characteristic heterogeneity of volcanic materials was taken into account. Therefore, a research campaign combining different methods was proposed; mechanical investigations traditionally applied in engineering (rotary boreholes, dynamic probing super heavy tests and pits) and geophysical methods (seismic refraction tomography and electrical resistivity tomography) were both utilized. The aims were to determine the geological structure of each site, detect possible anomalies or structures (i.e., faults, volcanic cavities, etc.), identify the different lithologies, determine the soil thickness and depth to bedrock, predict the excavatability of the materials, and obtain data about the physical properties and mechanical behaviour of the ground in an effort to carry out a geotechnical site characterization of both sites. At the site of the upper reservoir, electrical resistivity tomography recorded a high thickness of low resistivity soils, which were subsequently investigated by deep boreholes in order to sample and test them properly, since they could generate high settlements during the construction of the reservoir. At the site of the lower reservoir, the existing palaeorelief in the basaltic bedrock was detected by seismic refraction tomography, which allowed for the selection of the appropriate excavation machinery for the planned earthworks. The geological interpretation of the P‐wave velocity models and electrical resistivity models are shown in this paper, as well as a correlation between geotechnical parameters and geophysical properties of volcanic materials and recent deposits, which will be useful for other civil projects which may be carried out in the future at sites with similar geological conditions.

中文翻译：

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地震折射和电阻率层析成像技术，用于表征两个水库的岩土位置（西班牙埃耶罗）

在El Hierro（西班牙加那利群岛）上，Gorona del Viento El Hierro SA公司进行了风力发电站的建设，以通过100％可再生能源实现岛上的能源自主。该站由两个人造水库组成，它们的设计适应了岛上的地形，并被安置在一个山谷和一个不活跃的火山口中。为了研究两个储层的地下，考虑了火山岩材料的特征非均质性。因此，提出了结合不同方法的研究运动。都利用了传统上用于工程的机械研究（旋转钻孔，动态探测超重试验和矿坑）和地球物理方法（地震折射层析成像和电阻率层析成像）。目的是确定每个地点的地质结构，发现可能的异常或结构（即断层，火山洞等），识别不同的岩性，确定土壤厚度和基岩深度，预测材料的可开采性，并获取有关地面物理特性和机械行为的数据，以对两个站点进行岩土站点表征。在上部储层的现场，电阻层析成像记录了高厚度的低电阻率土壤，随后对这些深层钻孔进行了调查，以便对它们进行采样和正确测试，因为它们可能在储层建造过程中产生高沉降。在下水库的位置，地震折射层析成像技术可检测出玄武岩基岩中现有的古浮雕，从而为计划中的土方工程选择合适的开挖机械。本文显示了P波速度模型和电阻率模型的地质解释，以及火山岩材料和新近沉积物的岩土参数和地球物理特性之间的相关性，这对于可能进行的其他土建项目将是有用的将来在具有相似地质条件的地点开采。