Abstract On February 6, 2023, two earthquakes shook the southern and central Türkiye causing significant loss of human life and devastating many cities. These are related to the active East Anatolian Fault (EAF). In this study, the digital image correlation (DIC) technique is applied to map the coseismic displacements. For that, a pair of scenes from the Sentinel-2 satellite acquired before and after the seismic events was used. The results showed that the methodological approach can be effectively used to map and monitor large-scale geological phenomena and can assist in seismic risk assessment.

Abstract The geophysical diagnosis of mineral deposits can be extremely useful in detailing mineralized zones and is a strategy for direct sampling by probing holes for content analysis. This study involves the combined use of Electrical geophysical methods (DC resistivity and Induced Polarization), geological recognition and structural field analysis, with a study of the mineralized occurrence of copper, previously described in a systematic geochemical survey carried out by the Geological Survey of Brazil (CPRM), located in the north of the Camaquã Basin, extreme south of Brazil. The mineral occurrence is partially outcropped and consists of quartz vein shafts with malachite and relic structures of sulfides, contained in schist. Structural data obtained in the field revealed the existence of a system of fracture pairs in the directions N40-50W and N70-80E. Such information is presented in the programming of the geophysical data acquisition scheme, which consisted of 6 lines of electrical tomography with 410m each, in azimuthal disposition and Schlumberger arrangement, where all lines cross a single center and are separated according to an angle of 30°, in an attempt to cover fractures in various orientations. The 2D results reveal the existence of high chargeability zones (>40mV/V) positioned below the 40m depth. These data were interpolated in 3D visualization models and generated resistivity and chargeability maps for several depths, which integrated with previous structural data, and indicate the existence of zones with potential sulfide concentration with strong structural control, in addition to clear target recognition for direct and objective probing evaluation, with rationalization of costs.

Abstract The Precambrian metamorphic rocks in the southern region of the Espírito Santo State (southeastern Brazil) is intercepted by ductile and brittle/ductile shear zones over which towns like Guaçuí, Marechal Floriano and Domingos Martins were established. In the years of 2014 to 2016 the Espírito Santo State faced the worst drought in the past 80 years. In situations like that, the only source of fresh water available is underground. Therefore, the purpose of this study was to integrate multisource data for groundwater prospecting and management. The study area comprises the central sectors of the Guaçuí and Batatal shear zones. Methodology involved the interpretation of stereo-pairs for the identification of lineaments, electrical resistivity surveys and geological fieldwork. The results were tentatively validated with available groundwater well production data. Six resistivity profiles with a total length of 2,400 m were surveyed and 15 outcrops were described across these structures. Results have shown that the structural framework of the shear zones is predominantly made of NW to NNW and NE to NNE-trending lineaments. The former is related to brittle tectonics and the latter coincides with the ductile Precambrian fabric of the crystalline basement rocks. A near-surface porous aquifer regarded to the regolith and recent unconsolidated sedimentary deposits presenting resistivity values < 1,372 Ohm.m and depths < 30 m have good potential for groundwater storage. However, results are not conclusive about the hydrogeological significance of tectonic structures for groundwater prospection in the study area.

Resumen Las rocas metamórficas Precámbricas en la región sur del estado de Espírito Santo (sureste de Brasil) están interceptadas por zonas de cizallamiento dúctiles y quebradizas / dúctiles sobre las cuales se establecieron pueblos como Guaçuí, Marechal Floriano y Domingos Martins. En los años de 2014 a 2016, el estado de Espírito Santo enfrentó la peor sequía de los últimos 80 años. En situaciones como esa, la única fuente de agua dulce disponible es subterránea. Por lo tanto, el propósito de este estudio fue integrar datos de fuentes múltiples para la prospección y gestión de aguas subterráneas. El área de estudio comprende los sectores centrales de las zonas de cizallamiento Guaçuí y Batatal. La metodología abarca la interpretación de pares estereoscópicos para la identificación de lineamientos estructurales, prospección geofísica (resistividad eléctrica) y trabajos geológicos de campo. Los resultados se validaron tentativamente con los datos de producción de pozos de agua subterránea disponibles. Se estudiaron seis perfiles de resistividad con una longitud total de 2.400 m y se describieron 15 afloramientos. Los resultados mostraron que el marco estructural de las zonas de cizallamiento está hecho predominantemente de lineamientos de orientación NW a NNW y NE a NNE. La familia de orientación NW-NNW está relacionada con la tectónica frágil y la familia de orientación NE-NNE coincide con la trama dúctil Precámbrica de las rocas cristalinas del basamento. Un acuífero poroso superficial relacionado al regolito y a depósitos sedimentarios no consolidados recientes, con valores de resistividad < 1.372 Ohm.m y profundidades <30 m presenta un buen potencial para el almacenamiento de agua subterránea. Sin embargo, los resultados no son concluyentes sobre el significado hidrogeológico de las estructuras tectónicas para la prospección de aguas subterráneas en el área de estudio.

RESUMEN En la última década, la interferometría por dispersor persistente (PSI) se ha empleado para predecir inestabilidades en minas a cielo abierto. El PSI es una técnica poderosa que combina datos satelitales de radar para detectar y monitorear diminutos desplazamientos de superficie en vastas áreas. En los últimos años, la misión de radar Sentinel-1 ha producido imágenes del globo adquiridas con diferentes resoluciones espaciales y temporales que ahora están disponibles gratuitamente. En los últimos años, las laderas de las paredes de la mina de oro Riacho dos Machados - MRDM (provincia de Minas Gerais, sureste de Brasil) han registrado grandes rupturas planas controladas por planos de foliación. Por lo tanto, el objetivo de este trabajo es evaluar una pila de 39 imágenes IW (Interferometric Wide) del satélite Sentinel-1, que abarcan desde enero de 2018 hasta abril de 2019, adquiridas en geometría de órbita descendente, para la detección y monitoreo de desplazamientos de superficie en la MRDM. Los resultados han demostrado que las escenas descendentes IW Sentinel-1 se pueden utilizar para proporcionar una imagen amplia del fenómeno de deformación LOS (línea-de-visión). Para monitorear la evolución de los fenómenos de deformación inducidos por las actividades mineras, los mapas de deformación LOS con precisión milimétrica solo se pueden entregar al menos cada 12 días.

ABSTRACT In the last decade, the Persistent Scatterer Interferometry - PSI have been largely employed to predict instabilities and failure in open pit mines. The PSI is a powerful technique, which combines radar satellite data in order to detect and monitor tiny surface displacements over vast areas. In the last years, the Sentinel-1 radar mission have produced images of the globe acquired with different spatial and temporal resolutions that are now freely available. In recent years, the footwall slopes of the Riacho dos Machados Gold Mine - MRDM (Minas Gerais state, southeastern Brazil) have recorded large planar failures controlled by foliation planes. Therefore, the focus of this paper is to evaluate a stack of 39 Interferometric Wide Sentinel-1 scenes, spanning from January 2018 to April 2019, acquired in descending orbit geometry, for the detection and monitoring of surface displacements. The results have shown that descending IW Sentinel-1 scenes can be used to provide a broad picture of the Line-Of-Sight - LOS deformation phenomena. In order to monitor the evolution of the deformation phenomena induced by mining activities, LOS deformation maps with millimeter accuracy could be only delivered at least every 12 days.

Abstract Usually, stability conditions of excavation slopes are evaluated by means of kinematic analysis and geomechanical classification systems. However, field surveys are concentrated at the slope toe and information about the upper and internal portions of rock masses are not taken into account. In order to tackle with these issues multisources data were integrated. The studies were carried out in a marble quarry located in one of the largest Brazilian poles of dimension stones. Results have shown that drone images actually help in the structural characterization of rock masses because they allow to classify variable degrees of fracturing and to identify structural domains in the entire slope face. In addition, the number of discontinuities interpreted from drone images was much larger than that determined by scanline survey methods. This demonstrates that the subsampling of classical survey methods may significantly affect slope stability assessment. Results have also shown that the intensive use of explosives as a method for rock dismantling was an important mechanism of fracture generation. The electrical resistivity tomography method coupled with the other survey methods employed in this work, proved an important tool for rock mass characterization and quarry exploitation, since it allowed identifying and assessing subsurface fractured zone.

Abstract 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.

Abstract The management and monitoring of mechanized tunnel excavation parameters are crucial for ensuring the safety, quality and project's time/costs, since these parameters are the only existing elements that enable the evaluation of the performance of the excavation itself. In this study, will be presented the computational tool christened as SAPE (Support System and Monitoring of Underground Excavation Parameters), an innovative tool meant to assist the monitoring of ongoing or completed mechanized tunneling projects. The tool was designed to be a flexible and simple management tool, which means that it can be customized as a function of the characteristics of each project. The default version comprises the most important excavation parameters (a total of 14). Besides, it has important functions, such as geolocation (GoogleEarth program), historical production data and basic excavation statistics. The software was tested in the recently completed twin tunnels of the Subway Line 5 - Lilac in the city of São Paulo, Brazil.