Critical thresholds for landslides in Rio de Janeiro/RJ, Brazil

摘要

Over the past decades, in several areas around the world an increase of socio-environmental disasters associated to landslides has been observed. The city of Rio de Janeiro/RJ, Brazil, has geological and geomorphological characteristics favorable to the occurrence of mass movements, fostered by an increase in the population located hilly areas. Analyses in different regions of the city show the beneficial effect of the prevention works in charge of the GEO-RIO. For this study, two different periods were chosen for comparison, 1998 to 2002 and 2010 to 2012. For those periods, critical rainfall thresholds defined for 10 sub-regions of the city, using rainfall events and their corresponding mass movements, were established. As expected, the interventions on the slopes had a beneficial effect on the stability of the city slopes and an increase of the critical thresholds for landslides. Nevertheless, the disordered occupation of the city in high landslide susceptibility areas tend to worsen those indexes.