1Graduate Program in Natural Disasters, Unesp/Cemaden, São José dos Campos, Brazil
2National Center for Monitoring and Early Warning of Natural Disasters (Cemaden), São José dos Campos, Brazil
3National Institute of Education, Earth Observatory of Singapore and Asian School of the Environment, Nanyang Technological University (NTU), Singapore
4Institute of Earth Sciences, Academia Sinica, Taiwan
5Institute of Science and Technology, São Paulo State University (Unesp), Department of Environmental Engineering, São José dos Campos, Brazil
6University of Campinas, Institute of Geosciences (IG/Unicamp), Brazil
7Institute of Advanced Studies, University of São Paulo (IEA/USP), São Paulo, Brazil
1Graduate Program in Natural Disasters, Unesp/Cemaden, São José dos Campos, Brazil
2National Center for Monitoring and Early Warning of Natural Disasters (Cemaden), São José dos Campos, Brazil
3National Institute of Education, Earth Observatory of Singapore and Asian School of the Environment, Nanyang Technological University (NTU), Singapore
4Institute of Earth Sciences, Academia Sinica, Taiwan
5Institute of Science and Technology, São Paulo State University (Unesp), Department of Environmental Engineering, São José dos Campos, Brazil
6University of Campinas, Institute of Geosciences (IG/Unicamp), Brazil
7Institute of Advanced Studies, University of São Paulo (IEA/USP), São Paulo, Brazil
Received: 02 Jun 2022 – Discussion started: 10 Jun 2022
Abstract. On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually high volume of rain within three hours (258 mm). It resulted in flash floods and subsequent landslides that caused 231 fatalities, the deadliest landslide disaster recorded in Petrópolis. In this paper, we analyzed the root cause and the key triggering factors of this landslide disaster by assessing the spatial relationship of landslide occurrence with various environmental factors. Rainfall data were retrieved from 1977 to 2022, while other remote sensing data from 1985 to 2020, were utilized to map the landslide scars, soil moisture, terrain attributes, line-of-sight displacement (land surface deformation), and urban sprawling .. to. The results showed that the average rainfall for February 2022 was 200 mm, the heaviest recorded in Petrópolis since 1932. From the rainfall spatial distribution, heavy rainfall was also recorded mostly in regions where the landslide occurred. As for terrain, 23 % of slopes between 45–60° had landslide occurrences and east-facing slopes appeared to be the most conducive for landslides as they recorded landslide occurrences of about 9 to 11 %. Regarding the soil moisture, higher variability was found in the lower altitude (842 m) where the residential area is concentrated. From our land deformation assessment, the area is geologically stable, and the landslide occurred only in the thin layer at the surface of the 1,700 buildings found in the region of interest, 1,021 are on the slope between 20 to 45° and about 60 houses were directly affected by the landslides. As such, we conclude that the heavy rainfall was not the only cause responsible for the catastrophic event of February 15, 2022; a combination of unplanned urban growth on slopes between 45–60°, removal of vegetation, and the absence of inspection were also significant elements of this natural disaster.
The municipality of Petrópolis (approximately 305,687 inhabitants) is nestled in the mountains 68 km outside the city of Rio de Janeiro. On February 15, 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually high volume of rain within three hours (258 mm). It resulted in flash floods and subsequent landslides that caused 231 fatalities, the deadliest landslide disaster recorded in Petrópolis. This work showed how the disaster was triggered.
The municipality of Petrópolis (approximately 305,687 inhabitants) is nestled in the mountains...
