Proposta de correlação chuva vs escorregamento aplicada à cidade do Rio de Janeiro.

Abstract

In March and April of 2010, the city of Rio de Janeiro registered representative numbers of mass movement occurrences. Throughout 2010, according landslide report made by Fundação Geo-Rio and posted on Alerta Rio website, 627 incidents were recorded, of which about 76% occurred in April and 8% in March. The number of 2010 events, specifically its concentration in the months of March and April, drew attention to the mass movements recorded during these months, when compared to other rain events and occurrences in 2010. For the development of a correlation between rainfall and landslides, was admitted, as study area, a hillside known by Comunidade Formiga belonging to the Maciço da Tijuca, which is located in the city of Rio de Janeiro. The processing of data of landslide incidents, recorded in 2010 in the Comunidade Formiga, and rainfall events, recorded by pluviometric station Tijuca, allowed graphical analysis through empirical correlation method. To developing the graphical analisys were considered rains accumulated in 1 hour (mm/h), 24 h (mm/24) and 96h (mm/96h) before the landslides incident and rains accumulated in 1 hour (mm/h), 24 h (mm/24h ) and 96h (mm/96h) even when the rain event do not developed mass movements. Graphically it was developed three alternatives relating hourly rainfall (mm / h ) vs. day ( mm / 24 ) , hourly rainfall (mm / h ) vs. accumulated 4 days ( mm / 96h ) and daily rainfall (mm / 24 hours ) vs. accumulated 4 days ( mm / 96h ) , whose results indicated rainfall thresholds from which there is high probability of landslides . In addition to the study of correlation applied to the Comunidade Formiga, was developed a new rain correlation methodology vs landslide to the city of Rio de Janeiro, in what is considered excess rain at historical monthly average rain. The obtained rainfall thresholds would be used as reference to the activation of evacuation sirens.