Evaluation of susceptibility for terrain collapse and subsidence in karst areas, municipality of Iraquara, Chapada Diamantina (BA), Brazil.
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2018
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The morphological evolution of the karstic systems is associated with a set of physical and chemical processes, triggered by
the dissolution of the rocks, related to percolation of groundwater and surface water, which consequently open underground
voids and carve out peculiar forms of relief. Due to environmental and geotechnical aspects, this system is naturally more
fragile and vulnerable than other natural systems and, therefore, has increasingly received the attention of the scientific
community over the past decades. The objective of the study was to delimit zones with varying degrees of susceptibility for
collapses and subsidence of sinkholes in the municipality of Iraquara, Chapada Diamantina (BA), Brazil, and to understand
their geological and morphological determinant factors. Geological data, karst phenomenon map, and visual analysis in the
field were used to categorize zones with different types of susceptibilities to the nucleation of new sinkholes based on a
Hazard Index. This index was defined from the sum of geological hazard factors, lineament density, and sinkhole density.
The areas that presented the highest susceptibility for terrain collapse and subsidence corresponded to regions where carbonate
rocks outcrop, with high density of photolineaments and 2.62 sinkholes/km2. Processes associated with terrain collapse
and subsidence in karst areas consisted of a combination of various factors, hindering precise predictions. However, zones
of different types of susceptibilities to terrain collapse and subsidence can be delimited when the relationships between
these processes and their factors are understood. The Hazard Index proposed does not provide quantitative values for the
probability of hazard susceptibility, but rather indicates areas that are more susceptible to terrain subsidence and collapse.
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Carbonate rocks, Collapse and subsidence
Citação
SALLES, L de Q.; et al. Evaluation of susceptibility for terrain collapse and subsidence in karst areas, municipality of Iraquara, Chapada Diamantina (BA), Brazil. Environmental Earth Sciences, v. 77, p. 593, 2018. Disponível em: <https://link.springer.com/content/pdf/10.1007%2Fs12665-018-7769-8.pdf>. Acesso em: 11 fev. 2019.