Critical Rainfall Parameters: Proposed Landslide Warning System for the Metropolitan Region of Recife, PE, Brazil

Abstract

. In the Metropolitan Region of Recife, Northeast Brazil, landslides caused a total of 214 deaths between 1984 and 2012. Efforts have been made, but there is still need to improve the risk area management by discovering the correlations between the rainfall and landslides and by implementing a disaster warning and prevention system in order to reduce the number of accidents and fatalities. The purpose of this study is to propose rainfall parameters likely to trigger mass movements, as a contribution to risk management in this region. It specifically addresses the study undertaken in three municipalities: Recife, Camaragibe and Jaboatão dos Guararapes, which have disorganized occupation in high and very high risk areas. In order to achieve the prime objective, rainfall and landslides were tracked during 2009 to obtain correlations between them. After the data was logged, the rainfall accumulation associated with landslides was checked. According to each area with civil defense action of the municipalities involved in the study, critical values of the cumulative rainfall in 72 h (I72 h), in the long term (Pac) and the parameter Rcrit resulting from the product of I72 h by Pac, are suggested herein to be recommended for operations of the Warning and Alert states. By achieving these critical values, they increase the probability of landslide events, and are important for taking decisions and instructions on Civil Defense actions.