Geotechnical study in Formentera

On Formentera, the predominant geological substrate is mainly composed of limestones, dolomites and marbles, accompanied by deposits of compact gravel and sand. These materials provide good bearing-capacity conditions for foundations, although the significant presence of expansive white/soft clays in certain areas requires a detailed assessment of the strata before defining the type of support. The associated aquifers exhibit moderate permeability and yield, which may affect the hydraulic behaviour of the ground in excavations or deep foundations.

Seismic activity in Formentera is considered moderate, with a total of 24 events over 30 years and a maximum recorded magnitude of 3.2, which does not represent a relevant structural constraint. However, karst development must be checked meticulously, as the calcareous nature of the substrate may conceal cavities or subsidence phenomena that could compromise the stability of future foundations. Once the risk of expansivity has been ruled out due to the non-clayey nature of the predominant substrate, the main constraint for the geotechnical study is the potential presence of karst processes in the bedrock.