Estudio geotécnico in San Sebastián de la Gomera

In San Sebastián de la Gomera, the geological substrate is dominated by sandstones, conglomerates and flysch, which make up almost 88% of the soils present. These lithologies generally provide adequate bearing capacity for shallow foundations, although the bedded nature of the flysch may require additional checks to avoid differential settlement. The marginal presence of granite, gneiss and hardened igneous rocks suggests possible locally very competent substrate zones, suitable for foundations in specific cases. The aquifers in the area show moderate permeability and yield, implying the need to control the groundwater table during the execution of underground works.

As regards seismicity, the municipality is classified with a moderate level (12 events in 30 years) and a low maximum magnitude (Mmax 2.8), which reduces the impact of this factor on structural design. The absence of karst eliminates the risk of instability associated with dissolved cavities. Moreover, there is no evidence of significant expansivity in the substrate, ruling out risks due to swelling of clays. As a result, the main constraint to take into account in the geotechnical study of San Sebastián de la Gomera is the correct assessment of the heterogeneity of the sedimentary materials, especially the continuity and compaction of the flysch and conglomerates, in order to ensure a safe and stable foundation.