Assessment of physical vulnerability of buildings and socio-economic vulnerability of residents to rainfall induced cut slope failures: A case study in central highlands, Sri Lanka

Abstract

In landslide-prone areas, the vulnerability of housing structures is assessed so that adaptation methods can be introduced to reduce risk. Socio-economic consideration is vital when considering cut slope failures. This paper is an attempt to assess both the physical vulnerability of housing structures and the socioeconomic conditions of residents, to provide a holistic understanding of cut slope failure disasters. Extensive fieldwork is vital to understanding the correlation between the physical vulnerability of housing structures and socio-economic conditions due to a lack of relevant data at a household level. Data was collected using a questionnaire survey and extensive field survey, conducted with randomly selected households (N = 322) in Ambagamuwa, Sri Lanka. Factors that influenced living near slope failures were identified. The semi-quantitative methodology used to assess the physical vulnerability of buildings exposed to cut slope failures combines the landslide intensity and the building resistance capacity, and was empirically evaluated by using several indicators related to building characteristics. Regression analysis was used to analyze the correlation between the physical vulnerability of buildings and socio-economic parameters, which was a novel approach. The results reveal the choice to live in areas of cut slope failure risk was dependent on a number of different priorities for communities and that 82% of houses had a moderate vulnerability. Household per capita income and education level of the household head had a significant influence on vulnerability to cut slope failures. The findings in this paper will assist decision-makers in disaster risk reduction to introduce appropriate protective measures to both buildings and cut slope failure hazards, with consideration of the socio-economic conditions of the community, to increase building resistance capacity and decrease the intensity of cut slope failures.