ABSTRACT
In recent years Brazil has been undergoing changes in consciousness and management of natural disasters, considering the major events in 2008 and 2011. The magnitude of such events motivated the creation of Federal Law no. 12.608, which sets guidelines aimed at risk management and reduction of natural disasters in the country, with emphasis on preventive actions, such as the mapping of risk areas and geotechnical mapping. This work is part of an agreement between the Ministry of National Integration/National Secretariat of Civil Defense (MI/SEDEC) with the Federal University of Pernambuco/Group of Geotechnical Engineering regarding slopes, plains and disasters (UFPE / GEGEP). The municipality of Ipojuca in Pernambuco State (PE) was chosen as the pilot area. This municipality in recent years became one of the protagonists of the state economic scene, responsible for the second largest revenue in Pernambuco State. Alongside this growth, the town suffers from constant landslides on the occupied slopes, due to a physical and environmental setting prone to risk, and disorderly occupations. The Rurópolis community is the main representative of such a configuration. The purpose of this study is to chart the mass movement risks for a pilot area—the community Rurópolis in the municipality of Ipojuca, considering the factors associated with susceptibility and vulnerability. A methodology with reference to past experiences of susceptibility mappings by GEGEP/UFPE was developed. The vulnerability analysis was done considering two-dimensional indices: environmental and socioeconomic-cultural-physical. Environmental physical factors were obtained by observing all risk elements, such as building standards, hillside, and environmental degradation. The socioeconomic and cultural factors were obtained by interviewing residents in the study area, in order to learn the number of residents, the media used by the family, the presence of the elderly, children and disabled, social problems in the community, and other situations. Susceptibility was analyzed using indicators developed by evaluating the geological and geotechnical characteristics, geomorphology, soil science, land use and occupation. The risk was obtained by using a matrix that correlates the final degree of susceptibility and vulnerability. The risk level classification (low risk, medium risk, high risk and very high risk) was adopted. The study area is located south of the Ipojuca town center, the land area is 0.20 square kilometers, and at an average distance of 1.5 kilometers from the municipal buildings. According to IBGE (2014) the residential population in this area is approximately 7330. The study area was divided into 18 homogeneous sectors and the degree of risk was defined in these units. Sixteen sectors were defined as high risk (88% of the entire area of the sectors of the study area) and two sectors as low risk (12% of the total area of the study area sectors). Finally, it was evidenced that the form of disorderly occupation of the slopes is primarily responsible for causing landslides, the major type of movement found in the area.
