Seismic Risk Analysis of the Rammed Earth Residential Buildings in Niebla (Huelva, Spain)

Niebla is the oldest monumental city in the province of Huelva, located in an area of high seismic hazard in the region of Andalucía, in the South-East of Spain. The walled historic centre, declared historic-artistic site in 1982, has a rich earthen heritage. The Almohad walls, the largest and best-preserved in Europe, are certainly noteworthy. However, equal attention should be given to the traditional earthen residential houses built using the rammed-earth technique. This study is focused on the analysis of the seismic vulnerability of a sample of the traditional earthen rammed earth residential dwellings in the historic centre of Niebla, which would suffer from significant damages in the event of an earthquake of intensity VII in the region. The vulnerability has been assessed with the Vulnerability Index Method (L1 Risk-UE VIM) adapted to take into account the specific characteristics of the earthen residential buildings. Additionally, considering the heritage value of the historic built ensemble, losses have been obtained in terms of damaged built area, as the economic value cannot be calculated. The research highlights the significant impact an earthquake could have on these buildings. It also underscores the urgent need to develop strengthening solutions to reduce their seismic vulnerability, ensuring their long-term conservation and preservation.