O fluxo de massa do Vieira, Teresópolis-RJ, megadesastre da serra em 2011: análise das feições sedimentológicas e de sua fenomenalogia

Abstract

In January 2011, a large number of natural and induced landslides hit the mountainous region of Rio de Janeiro State, during the megadesastre , which is destructive processes of great impact, but with greater recurrencetime. In particular, the Vieira River basin (northwest of Teresópolis), affected by the event, registered a big magnitude of the disaster with mobilized materials in mass flows reaching distances of kilometers from their main scarps, what caused hours later, significant damages. This dissertation research discussed these processes characterization and its depositional environments, from a sedimentological analysis of those features and assessing their mechanical characteristics of Vieira river valley to establish the knowledge of local landscape evolution. The results characterize the phenomenon in geological, geomorphological and stratigraphicterms. Vieira river channel was afcted by a gravity flow from its source, at 1750m in elevation, to its end on its floodplain, at elevation 900m, was carachterized as a mass movement with an extension of 7.5 km, 30-100m wide and 4m thick, directly caused 86 deaths and alsohouses and crops destruction at rural neighborhood from Vieira, Teresópolis, Rio de Janeiro. The gravity flow of Vieira River apparently had different conditions and different stages involved, from debrisflow to mud-flow, probably in different pulses, and in its final stage being water flow.