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Deslizamentos na região de Arruda dos Vinhos numa perspetiva regional e local: resultados preliminares
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Advisor(s)
Abstract(s)
A Região Norte de Lisboa de uma forma geral, e a região
de Arruda dos Vinhos em particular, apresentam condições naturais
bastante favoráveis à ocorrência de movimentos de massa. Neste
trabalho analisou-se o comportamento hidrodinâmico da bacia
hidrográfica do Rio Grande da Pipa de modo a perceber a sua
importância na estabilidade das vertentes desta região. Analisaram-se
também as condições locais que favorecem a instabilidade das
vertentes, através de retroanálises a dois deslizamentos. A
comparação entre a ocorrência temporal dos 182 deslizamentos e a
oscilação do nível freático regional revela uma associação evidente
entre ambas as distribuições. Os deslizamentos associados ao
Complexo das Camadas da Abadia, nomeadamente os que são
superficiais ou de profundidade intermédia e do tipo rotacional,
parecem ser mais sensíveis às oscilações do nível freático. Por outro
lado, os movimentos profundos não parecem ocorrer em maior
frequência para níveis freáticos regionais elevados. As retroanálises
de dois deslizamentos rotacionais profundos, estudados à escala
local, parecem indicar que as suas ocorrências estão fortemente
associadas a reativações de movimentos antigos e a intervenções
humanas nas vertentes.
In general the north area of Lisbon and the Arruda dos Vinhos region in particular have natural conditions that greatly favour the occurrence of slope mass movements. In this study we analysed the hydrodynamic character of the Rio Grande da Pipa watershed in order to understand its influence in the stability of natural slopes. Local conditions affecting their stability were also analysed through back-analysis for two selected landslides. The comparison between temporal occurrences of 182 landslides that occurred in the hydrological year 2009/10 and the fluctuation of the regional water table reveals a clear association between both distributions. Shallow and intermediate deep-seated rotational landslides in the marls of Abadia geological unit are those that seem more sensitive to water table fluctuations. On the other hand, deepseated landslides do not seem to occur more frequently during periods of high regional water table. The detail analyses of the two deep-seated and rotational landslides suggest that their occurrences correspond mainly to reactivations of past landslides and were influenced by human interventions in the area.
In general the north area of Lisbon and the Arruda dos Vinhos region in particular have natural conditions that greatly favour the occurrence of slope mass movements. In this study we analysed the hydrodynamic character of the Rio Grande da Pipa watershed in order to understand its influence in the stability of natural slopes. Local conditions affecting their stability were also analysed through back-analysis for two selected landslides. The comparison between temporal occurrences of 182 landslides that occurred in the hydrological year 2009/10 and the fluctuation of the regional water table reveals a clear association between both distributions. Shallow and intermediate deep-seated rotational landslides in the marls of Abadia geological unit are those that seem more sensitive to water table fluctuations. On the other hand, deepseated landslides do not seem to occur more frequently during periods of high regional water table. The detail analyses of the two deep-seated and rotational landslides suggest that their occurrences correspond mainly to reactivations of past landslides and were influenced by human interventions in the area.
Description
Keywords
Deslizamentos Arruda dos Vinhos Margas Hidrologia
Pedagogical Context
Citation
Jesus, C. C., Oliveira, S. C., Sena, C. & Marques, F. (2014). Deslizamentos na região de Arruda dos Vinhos numa perspetiva regional e local: resultados preliminares. Comunicações Geológicas, 101, Especial II, 903-906. http://www.lneg.pt/iedt/unidades/16/paginas/26/30/185
Publisher
Laboratório Nacional de Energia e Geologia