Correlation between rainfall and landslides in Nova Friburgo, Rio de Janeiro-Brazil: a case study

Rainfall is recognized as one of the main factors that influence the triggering of landslides in mountainous regions. The city of Nova Friburgo, which is located in the elevated regions of Rio de Janeiro-Brazil, suffers constantly from landslides usually associated with extreme rainfall events. Under this framework, an empirical study was conducted to analyze records from the rain gauge Ypu jointly with landslides dataset in order to define accumulated precipitation thresholds associated to the occurrence of mass movements in the referred municipality. In addition, we examined the relationship between the Ypu rainfall dataset and the rainfall estimated by Tropical Rainfall Measuring Mission (TRMM) satellite for the pixel in which the rain gauge Ypu is located to assess the representativeness of both types of measurements in our case study due to the rugged features of the relief. The TRMM data revealed a similar behavior to the Ypu in situ data surface, highlighting a correlation of 0.5 (R-2 = 0.25). The study showed that the integrated analyses between the rainfall and landslides provided important information to contribute to decision making in the city of Nova Friburgo-RJ, especially with regard to the issuance of warnings and alerts to the responsible agencies and population.