Vulnerability to Rainfall-Induced Landslide of Three Communities in Infanta, Quezon, Philippines

Abstract

Four successive tropical cyclones hit the Philippines and brought damages to several towns in the provinces of Quezon and Aurora between November 14 and December 4 in 2004. The municipalities of Infanta, Real, and General Nakar were severely damaged and as a result the communities were exposed to physical risks and experienced socio-economic difficulties. To affect policies and plans in avoiding risks brought about by disasters that may happen in the future, the vulnerabilities to rainfall-induced landslide of the three most devastated barangays in Infanta, Quezon, namely Pinaglapatan, Ilog, and Magsaysay, were determined using an agent-based model. This study determined the vulnerability of three communities based on the framework that vulnerability is influenced by the amount and intensity of rainfall received by the area in a given time, the conditions of the biophysical characteristics of the area, and the socio-economic profile of the community in the area. A time series model to capture the long-term rainfall pattern in the area was developed with consideration to the occurrences of extreme events. Biophysical studies were conducted on the study sites to determine their respective characteristics using topography (slope and elevation), land-use, and soil type as parameters. Through a respondent-type survey, the socio-economic profiles of the communities were characterized using income, livelihood, participation in social networks, and existence of community early warning systems, among others, as parameters. Because of the barangay