Estudio geotécnico in Urnieta

In Urnieta, the predominant geological substrate is mainly composed of shales and schists, with occasional occurrences of limestones, dolomites, marbles and, to a lesser extent, sandstones, conglomerates and flysch. These lithologies are characterised by their low permeability, which limits the formation of deep aquifers and favours general stability for foundations. However, strength and bearing capacity may vary locally due to the fracturing of the schists and the presence of more competent materials such as limestones; therefore, a detailed geotechnical study is recommended to define the most suitable type of foundation.

Seismic activity in the municipality is very low, with barely 4 events in the last 30 years and a maximum recorded magnitude of 2.6, which implies a low seismic risk for structural design. However, the occurrence of calcareous formations makes it essential to verify the possible presence of karst phenomena before carrying out any foundation works, due to the susceptibility of limestones to the development of underground cavities. The main conditioning factor in Urnieta is therefore the assessment of the potential for karstification in areas where limestones occur.