A 3D geological model of El Hierro volcanic island reflecting intraplate volcanism cycles

Abstract

Fully 3D and multidimensional geological models are key for energy, mining and water resources assessment and management, which has a great economic impact. 3D geological models provide critical information regarding geometric properties of the geological bodies of interest, such as ore deposits or reservoirs, allowing inference of volumes and availability to be exploited. However, defining a useful methodology to create a fully digital 3D geological model of volcanic islands is still very challenging due to the intrinsic complexity observed in the structure of volcanic systems. Two-dimensional geological maps, associated vertical geological cross-sectional diagrams and borehole and water-mining tunnels (galleries) logs were examined on El Hierro Island. A geological modelling procedure using the software GeoModeller obtained the first 3D geological model of El Hierro volcanic island, as a basis for volcanic formation definitions and geometric analysis. Surface, volume and center of mass estimations of the differentiated sub-units allowed a better understanding of the spatial distribution and evolution of the volcanic cycles of El Hierro Island over time. The 3D model provided geometry information correlatable with volcanic activity cycles and lava/pyroclast deposition mechanisms that ultimately defines the geometry of the volcanic units. This information provides new variables valuable for the investigation of the existing relationships between rift zones and giant lateral collapses. In addition, the obtained 3D geological model of a volcanic island will support the building of the first hydrogeological and geothermal model of El Hierro Island, allowing advancement of sustainability of isolated systems.