Abstract:
Debris flows represent great hazard to humans due to their high destructive power. Understanding their hydrogeomorphic dynamics is fundamental in hazard assessment studies, especially in subtropical and tropical regions where debris flows have scarcely been studied when compared to other mass-wasting processes. Thus, this study aims at systematically analyzing the meteorological and geomorphological factors that characterize a landslidetriggered debris flow at the Pedra Branca catchment (Serra do Mar, Brazil), to quantify the debris flow’s magnitude, peak discharge and velocity. A magnitude comparison with empirical equations (Italian Alps, Taiwan, Serra do Mar) is also conducted. The meteorological analysis is based on satellite data and rain gauge measurements, while the geomorphological characterization is based on terrestrial and aerial investigations, with high spatial resolution. The results indicate that it was a large-sized stony debris flow, with a total magnitude of 120,195 m3, a peak discharge of 2146.7 m3 s− 1 and a peak velocity of 26.5 m s− 1. The debris flow was triggered by a 188-mm rainfall in 3 h (maximum intensity of 128 mm h− 1), with an estimated return period of 15 to 20 years, which, combined with the intense accumulation of on-channel debris (ca. 37,000 m3), indicates that new highmagnitude debris flows in the catchment and the region are likely to occur within the next two decades. The knowledge of the potential frequency and magnitude (F–M) can support the creation of F–M relationships for Serra do Mar, a prerequisite for reliable hazard management and monitoring program.
Reference:
CABRAL, Victor Carvalho; REIS, Fábio Augusto Gomes Vieira; D’AFONSECA, Fernando Mazo; LUCÍA, Ana; CORRÊA, Claudia Vanessa dos Santos; VELOSO, Vinicius; GRAMANI, Marcelo Fischer; OGURA, Agostinho Tadashi; LAZARETTI, Andrea Fregolente; VEMADO, Felipe; PEREIRA FILHO, Augusto José; SANTOS, Claudia Cristina dos; LOPES, Eymar Silva Sampaio; RABACO, Lis Maria Reoni; GIORDANO, Lucilia do Carmo; ZARF, Christiane. Characterization of a landslide triggered debris fow at a rainforest covered mountain region in Brazil. Natural Hazards, 23 p., May, 2021.
Access to the article on the Journal website:
https://link.springer.com/content/pdf/10.1007/s11069-021-04811-9.pdf
Debris flows represent great hazard to humans due to their high destructive power. Understanding their hydrogeomorphic dynamics is fundamental in hazard assessment studies, especially in subtropical and tropical regions where debris flows have scarcely been studied when compared to other mass-wasting processes. Thus, this study aims at systematically analyzing the meteorological and geomorphological factors that characterize a landslidetriggered debris flow at the Pedra Branca catchment (Serra do Mar, Brazil), to quantify the debris flow’s magnitude, peak discharge and velocity. A magnitude comparison with empirical equations (Italian Alps, Taiwan, Serra do Mar) is also conducted. The meteorological analysis is based on satellite data and rain gauge measurements, while the geomorphological characterization is based on terrestrial and aerial investigations, with high spatial resolution. The results indicate that it was a large-sized stony debris flow, with a total magnitude of 120,195 m3, a peak discharge of 2146.7 m3 s− 1 and a peak velocity of 26.5 m s− 1. The debris flow was triggered by a 188-mm rainfall in 3 h (maximum intensity of 128 mm h− 1), with an estimated return period of 15 to 20 years, which, combined with the intense accumulation of on-channel debris (ca. 37,000 m3), indicates that new highmagnitude debris flows in the catchment and the region are likely to occur within the next two decades. The knowledge of the potential frequency and magnitude (F–M) can support the creation of F–M relationships for Serra do Mar, a prerequisite for reliable hazard management and monitoring program.
Reference:
CABRAL, Victor Carvalho; REIS, Fábio Augusto Gomes Vieira; D’AFONSECA, Fernando Mazo; LUCÍA, Ana; CORRÊA, Claudia Vanessa dos Santos; VELOSO, Vinicius; GRAMANI, Marcelo Fischer; OGURA, Agostinho Tadashi; LAZARETTI, Andrea Fregolente; VEMADO, Felipe; PEREIRA FILHO, Augusto José; SANTOS, Claudia Cristina dos; LOPES, Eymar Silva Sampaio; RABACO, Lis Maria Reoni; GIORDANO, Lucilia do Carmo; ZARF, Christiane. Characterization of a landslide triggered debris fow at a rainforest covered mountain region in Brazil. Natural Hazards, 23 p., May, 2021.
Access to the article on the Journal website:
https://link.springer.com/content/pdf/10.1007/s11069-021-04811-9.pdf
