Movimento de blocos rochosos: um estudo acerca do risco e sua percepção no Morro do Cristo em Juiz de Fora-MG

Abstract

This research had as its objective to identify and detail risky points for mass movements – in the rock block movement typology – in the protected area of Morro do Cristo in Juiz de Fora, MG, as well as the perception of this risk by part of the population residing in the areas considered to be more vulnerable by its foothills. The study was developed in the part surrounded by the polygon made by the streets Espírito Santo and São Sebastião, running N-S and by the protected slope of Morro do Cristo and Av. Olegário Maciel, running W-E. the study was divided in four stages: on the first stage we sought to identify and evaluate the stability of the rock blocks with dimensions of or above 100x100x100cm. For that we used the rock block stabilization evaluation form (BRASIL, 2011). On the second stage we identified the movement typology of the blocks classified as unstable and very unstable (INFANTI and FORNASARI, 1998). On the third stage we elaborated a tree of faults and a diagram of cause and effect (ROCHA, 2005). On the fourth and last stage we verified the perception of risk that the residents of the more vulnerable areas suffer by means of semistructured interview, which were transcribed and had their content analyzed according to Bardin (1977). A total of thirty (30) were identified and evaluated, out of them, three (3) were found unstable and ten (10) very unstable. The falls and rolls presented themselves as common movements in the place. The results of the interviews revealed a low perception of risk by part of the residents. Natural and/or man-made consequences are the possible causes for the falls and/or rolls of rock blocks. The measures for the reduction of the instability of the rock blocks and consequent reduction of risk in the place are interventions liable to the public authorities. From this data it is possible to point out a high-risk condition for the rock block movements in the studied area.