Seismic risk evaluation including the social context for the city of Mérida, Venezuela

This article presents a holistic and comprehensive approach for seismic risk assessment which involves the evaluation of the social fragility and the lack of resilience of the study area. That means, involves the characteristics of the social context that can exacerbated the situation when a hazardous event occurs. The proposed methodology allows a standardized assessment of the social fragility and lack of resilience, by means of an aggravation coefficient of which summarizes the characteristics of the social context using fuzzy sets and analytic hierarchy process. The selection of 20 social indicators is based on the indicators used by urban observatories of United Nations and other social researchers. These indicators are classified in six categories according to social item they describe: i) Dwelling, ii) Social development and poverty eradication, iii) Urban Planning, iv) Governance, v) Lack of resilience and vi) Demography. Applying the determination level analysis, thirteen prevailing social indicators are selected. The proposed methodology was applied to the city of Merida (Venezuela). The average value of seismic physical risk was low and high for intensities VIII and IX respectively. However, parishes present results with important differences among them. The average value of the aggravation coefficient is medium. The average total seismic risk is moderate and very high for intensity VIII and IX respectively. According to the obtained results, the social context substantially aggravates the seismic physical risk in 5 of the 11 city parishes. Seven of them have a very high level of total seismic risk.