Residential Building Site Suitability Assessment and Mapping, Philippines

Abstract. This paper suggests a novel method to site suitability mapping in the Philippines. In a country where natural hazards pose a serious threat to human development the assessment of the potential impacts of such hazards is of central importance. However, up to now, no comprehensive, nationwide, probabilistic risk assessments have been conducted resulting in vague qualitative risks estimations and in turn large uncertainties for site suitability assessments. Taking asset-specific vulnerabilities into consideration, the new approach here estimates the physical damage caused by six natural hazards, and this leads to a solid risk estimation with a resolution of 30 m. Such an estimation forms the backbone of site suitability. Other factors influencing suitability depend largely on subjective preferences like the closeness of hospitals or shopping facilities. The suggested method can facilitate an infinite number of factors if they can be geographically located. As an example, the proximity to population and to roads was introduced here. A single, detached, residential building with medium fragility served as a sample asset. The risk assessment revealed a strong gradient of risk, and by extension site suitability, from relatively low values for the southwest to higher values in the north of the Philippines, if all other factors are equal. Coastal areas are especially at risk because of the tsunami and storm surge hazards and thus, generally less suitable for residential buildings.