Persistent Scatterer interferometry (PSI) represents a powerful tool for the detection and monitoring of tiny surface deformations in vast areas, allowing a better understanding of its triggering mechanisms, planning of mitigation measures, as well as to find better solutions for social and environmental issues. However, there is no record hitherto of its use in active open pit mine in tropical rainforest environment. In this paper we evaluate the use of the PSI technique for the detection and monitoring of mine slope deformations in the N4W iron mine and its surroundings, Pará State, Northern Brazil. The PSI processing was performed with 18 ascending SAR scenes of the TerraSAR-X satellite acquired in the dry season of 2012. The results showed a significant number of widely distributed persistent scatterers. It was observed that most of the study area was stable during the time span. Nevertheless, high deformation rates (312 mm/year) were mapped over the mine waste piles, but do not offer any hazard, since they are expected displacements of meters in magnitude for these manmade land structures. Additionally, it was mapped tiny deformation rates in both the east and west flanks of pits 1 and 2. The main underlying reasons can be assigned to the accommodation phenomena of very poor rock masses, to the local geometric variations of the slope cuts, to the geological contact between ironstones and the country rocks, to the exploitation activities, as well as to the OPEN ACCESS Remote Sens. 2013, 5 4720 major geological structures. This study showed the applicability of the PSI technique using TerraSAR-X scenes in active open pit mines in tropical moist environment. However, the PSI technique is not capable in providing real-time warnings, and faces limitations due to SAR viewing geometry. In this sense, we strongly recommend the use of radar scenes acquired in both ascending and descending orbits, which would also provide a more complete understanding of the deformation patterns.

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Abstract. The Azul mining complex, located in the Carajás Mineral Province, Amazon region, encompasses the most important manganese mine in Brazil. Vale S.A. company operates three simultaneous open pit excavations (mines 1, 2, and 3) in the area, which are conducted on rock alteration products of low geomechanical quality related to sandstones, siltstones, and a lateritic cover. In order to monitor ground deformation, 33 TerraSAR-X (TSX-1) StripMap images covering the period of March 2012-April 2013 were used in the investigation. An advanced differential interferometric synthetic aperture radar (A-DInSAR) approach based on persistent scatterer interferometry (PSI) using an interferometric point target analysis algorithm was applied, and the results showed that most of the area was considered stable during the time span of the synthetic aperture radar acquisitions. However, persistent scatterers (PS) with high deformation rates were mapped over a waste pile, probably related to settlements, and also along the north flank of mine 1, indicative of cut slope movements toward the center of the pit. A spatial relationship of geological structures with PS was observed for this sector of the mine, given by PS showing deformation rates concentrated along a structural corridor with faults, fractures, and folds related to the Carajás fault system. Though only ground-based radar measurements for wall benches of mine 1 were available for a short time period of the TSX-1 coverage, the PS movement patterns showed concordance with geotechnical field measurements. The investigation emphasized the important role that satellite-based A-DInSAR can play for deformation monitoring and risk assessment in this kind of mining area. © The Authors.Published by SPIE under a Creative CommonsAttribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requiresfull attribution of the original publication, including its DOI.

ResumoAspectos referentes à morfogênese mesozóico-cenozóica da Serra dos Órgãos no Estado do Rio de Janeiro, região sudeste do Brasil, foram investigados por meio da análise morfotectônica. Os resultados permitiram reconhecer padrões anômalos na rede de drenagem e nas formas de relevo, que encontram correspondência com dois eventos tectônicos superpostos, de caráter regional, no sudeste do país. O primeiro evento tectônico teria operado no Eoceno, caracterizado por distensão de direção NW-SE, considerado como gerador do Rift Continental do Sudeste do Brasil. Sua principal conseqüência seria a compartimentação do relevo em blocos alongados e escalonados abatidos para sudeste. Concomitantemente a este abatimento, deu-se a deformação de uma antiga superfície de aplainamento, que teria nivelado a cimeira da Serra dos Órgãos em torno de 2.000 m s.n.m. O regime tectônico seguinte, caracterizado por cisalhamento destral, com binário E-W, de idade pleistocênica a holocênica, envolveria uma retomada dos processos erosivos, com desenvolvimento de drenagens ao longo de lineamentos de direção NW-SE, hoje realçadas pelas facetas trapezoidais parcialmente preservadas ao longo do vale do rio do Bonfim.Palavras-chave: análise morfotectônica, Serra dos Órgãos, sudeste do Brasil Abstract Mezosoic-Cenozoic morphogenesis of the Serra dos Órgãos range in the Rio de Janeiro State, southeastern Brazil, was investigated using morphostructural analysis. Results revealed anomalous pattern of the drainage network and landforms, that are related with two superimposed tectonic events observed regionally in southeastern Brazil. The first tectonic event operated in Eocene and was characterized by a NW-SE-trending extensional regime, considered as generator of Continental Rift of Southeastern Brazil. It was responsible for the relief segmentation in the south-southeast part of the study area, where NE-SW-trending elongated blocks in a step-like array descending to the southeast are observed. At the same time occurred the deformation of an old erosion surface, which had previously leveled the summit of the Serra dos Órgãos range at around 2.000 m a.s.l. The next tectonic event was characterized by Late Pleistocene-Holocene right-lateral E-W-trending strike-slip, with NW-SE compression which reactivated erosive process, with development of drainages along NW-SE-trending lineaments, enhanced today by the trapezoidal facets partially preserved along the Bonfim river valley.Keywords: morphotectonic analysis, Serra dos Órgãos range, southeastern Brazil IntroduçãoAnálises morfométricas e modelos numéricos do terreno são modelagens matemáticas computacionais do relevo que apresentam grande aplicação em estudos morfotectônicos, e podem ser obtidas a partir do processamento de cartas topográficas, fotografias aéreas ou, mais recentemente, dados

The Guacuí and Batatal lineaments in the southern region of the state of Espírito Santo (southeastern Brazil) can be traced from satellite images for tens of kilometers. They are considered shear zones associated to the final tectonic stages of the Araçuaí-West Congo (A-WC) Orogen during the Ediacaran-Cambrian period. In order to understand their nature and tectonic implications for the development of the orogeny, we integrated geological and structural data based on fieldwork and detailed microstructural analysis. Data was collected along two profiles located at the central segments of both structures. The results demonstrated that the Guaçuí shear zone (GSZ) is a typical ductile transpressive shear zone with approximately 9 km width that shows numerous dextral kinematic indicators and records metamorphism of upper amphibolite facies. The GSZ shows different levels of intensity of dynamic deformation. The Batatal shear zone (BSZ) is a narrow brittle shear zone that shows essentially brittle microstructures (intercrystalline microfractures) revealing deformation at low-grade conditions (frictional regime). Based on their characteristics and the level of erosion of the rocks exposed in the region, we interpret that GSZ developed prior to BSZ.