scholarly journals Analysis of the Geological Controls and Kinematics of the Chgega Landslide (Mateur, Tunisia) Exploiting Photogrammetry and InSAR Technologies

2021 ◽  
Vol 13 (20) ◽  
pp. 4048
Author(s):  
Seifeddine Gaidi ◽  
Jorge Pedro Galve ◽  
Fetheddine Melki ◽  
Patricia Ruano ◽  
Cristina Reyes-Carmona ◽  
...  
Keyword(s):  
Mass Movement ◽  
Normal Faults ◽  
Interferometric Synthetic Aperture Radar ◽  
Northern Tunisia ◽  
Progressive Movement ◽  
Complex Landslide ◽  
Aerial Vehicle ◽  
Block Slide ◽  
Landslide Movement

Exploration of territories not previously analyzed by landslide experts provides interesting findings. The Chgega landslide, in northern Tunisia, represents a paradigmatic mass movement. It can be classified as a complex landslide, or more specifically as vast rock spreading that evolved into a block slide. It involves a great block of limestone—about 900 m long and 400 m wide—sliding over ductile clays and marls. The viscoplastic creep of the clays drives the landslide and creates, in its crown, a graben ~800 m long and ~120 m wide that breaks the summit of Chgega Mountain. Using Interferometric Synthetic Aperture Radar (InSAR) technologies, we demonstrate that this complex landslide is currently active and moreover shows progressive movement without clear episodic accelerations. The velocity of the limestone block is just above 2 mm/yr. The occurrence of gravity-induced joints indicates that the movement has an orientation towards 333° of azimuth on average, conditioned by the landscape around Chgega. These results were obtained through the analysis of a 3D model and a high-resolution orthoimage created from photographs acquired by an Uncrewed Aerial Vehicle (UAV). We may conclude that the landslide movement is determined by normal faults with directions N060°E and N140–150°E. This characterization of the Chgega landslide can serve as the basis for future studies about the origin of this slope movement. Furthermore, the data provided here may support the recognition of Chgega as a singular geological point that deserves to be declared a geosite.

scholarly journals Surface and Underground Geomechanical Characterization of an Area Affected by Instability Phenomena in Zaruma Mining Zone (Ecuador)

2021 ◽  
Vol 13 (6) ◽  
pp. 3272
Author(s):  
Paúl Carrión-Mero ◽  
Maribel Aguilar-Aguilar ◽  
Fernando Morante-Carballo ◽  
María José Domínguez-Cuesta ◽  
Cristhian Sánchez-Padilla ◽  
...  
Keyword(s):  
Mass Movement ◽  
Mining Activity ◽  
Mining District ◽  
Mean Values ◽  
Surface Areas ◽  
Definition Of ◽  
Action Measures ◽  
Geomechanical Characterization ◽  
The City

In the last decade, in the mining district of Zaruma-Portovelo, there has been significant land subsidence related to uncontrolled mining activity. The purpose of this work was to carry out a surface and underground geomechanical characterization of a mining sector north of the city of Zaruma that allows the definition of potentially unstable areas susceptible to the mass movement. The methodology used consists of the following stages: (i) compilation of previous studies; (ii) surface and underground characterization of rocky material to establish its susceptibility to mass movement; (iii) interpretation of results; and (iv) proposal of action measures. Among the most relevant results, it stands out that 26.1% of the 23 stations characterized on the surface present conditions that vary from potentially unstable to unstable. In underground galleries, the studied mean values of the 17 stations indicate that the rock has a medium to good quality, representing a medium susceptibility to gallery destabilization. The results obtained for the surface areas (depths up to 50 m, where altered materials predominate) and the underground areas (depths > 50 m, where the alterations are specific) can be used to identify the areas with a more significant potential for instability. For both cases, it has been possible to define specific monitoring, control, and planning actions for sensitive areas.

Dynamic Characterization of Brushless DC Motors and Propellers for Flight Applications

2017 ◽  
Vol 05 (03) ◽  
pp. 159-167 ◽  
Author(s):  
Dominic Muzar ◽  
Eric Lanteigne ◽  
Justin McLeod
Keyword(s):  
Simple Model ◽  
Brushless Dc Motor ◽  
Dynamic Characterization ◽  
Brushless Dc Motors ◽  
Brushless Dc ◽  
Dc Motors ◽  
Simple Motor ◽  
Aerial Vehicle ◽  
Selection Of

Although there exist a number of accurate unmanned aerial vehicle (UAV) thruster models, these models require the precise measurements of several motor and propeller characteristics. This paper presents a simple motor and propeller model that relies solely upon data provided by manufacturers. The model is validated by comparing theoretical motor and propeller behavior to experimental results obtained from thrust tests in a wind tunnel. The objective is to provide an accurate yet simple model to facilitate the selection of appropriate brushless DC motor and propeller combinations for flight applications.

scholarly journals Effects of Motion Compensation Residual Error and Polarization Distortion on UAV-Borne PolInSAR

2021 ◽  
Vol 13 (4) ◽  
pp. 618
Author(s):  
Zexin Lv ◽  
Fangfang Li ◽  
Xiaolan Qiu ◽  
Chibiao Ding
Keyword(s):  
Motion Compensation ◽  
Residual Error ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Practical Application ◽  
Aerial Vehicle ◽  
Application Potential ◽  
Large Motion ◽  
Simulation Results ◽  
Interferometric Sar

Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) can improve interferometric coherence and phase quality, which has good application potential. With the development of the Mini-SAR system, Unmanned Aerial Vehicle borne (UAV-borne) PolInSAR systems became a reality. However, UAV-borne PolInSAR is easily affected by air currents and other factors, which may cause large motion errors and polarization distortion inevitably exists. However, there are few pieces of research which are about motion compensation residual error (MCRE) and polarization distortion effects on PolInSAR. Though the effects of MCRE on Interferometric SAR (InSAR) and polarization distortion on PolInSAR were studied, respectively, these two parts are independently modeled and analyzed. In this paper, a model that simultaneously considers the effects of these two kinds of errors is proposed, and simulation results are given to validate the model. Then, a quantitative analysis based on a real Quadcopter UAV PolInSAR system is performed according to the model, which is valuable for system design and practical application of the UAV-borne PolInSAR system.

Global Mapping and Analysis of the Structural Features in the Northern Smooth Plains of Mercury

2021 ◽  
Author(s):  
marco cardinale ◽  
Gaetano Di Achille ◽  
David A.Vaz
Keyword(s):  
Imaging System ◽  
Structural Features ◽  
Planetary Science ◽  
Altimeter Data ◽  
Normal Faults ◽  
Laser Altimeter ◽  
Volcanic Material ◽  
Geological Map ◽  
Dual Imaging

<p>Orbital data from the Messenger spacecraft (1) reveal that part of the Mercury surface is covered by smooth plains, which are interpreted to be flood volcanic material across the planetary surface (2). In this work, we present a detailed geo-structural map of the northern smooth plains between<span class="Apple-converted-space">  </span>latitudes 29°N and 65°N. Our 1:100.000-scale map is obtained semi-automatically, using an algorithm to map all scarps from a DEM (3,4) followed by visual inspection and classification in ArcGIS. We created a DEM<span class="Apple-converted-space">  </span>using the raw MLA (Mercury Laser Altimeter) data (1) ,with 500 m/pix, and we used the Mercury Messenger MDIS (Mercury Dual Imaging System) (1,2) base map with 166m per pixel for the classification stage. With this approach, we mapped and characterized 51664 features on Mercury, creating a database with several morphometric attributes (e.g. length, azimuth, scarp height) which we will use to study the tectonic evolution of the smooth plains.<span class="Apple-converted-space"> </span></p> <p>In this way, we classified wrinkle ridges’s scarps, ghost craters, rim craters and central peaks. The morphometric parameters of the wrinkle ridges will<span class="Apple-converted-space">  </span>be quantitatively analyzed, in order to characterizer the possible tectonic process that could have formed them.</p> <p>This map can be considered an enhancement for the north pole of the global geological map of Mercury (1, 5).</p> <p> </p> <p>References</p> <ul> <li>Hawkins, S. E., III, et al. (2007), The Mercury Dual Imaging System on the MESSENGER spacecraft, Space Sci. Rev., 131, 247–338..<span class="Apple-converted-space"> </span></li> <li>Denevi, B. W., et al. (2013), The distribution and origin of smooth plains on Mercury, J. Geophys. Res. Planets, 118, 891–907, doi:10.1002/jgre.20075.</li> <li>Alegre Vaz, D. (2011). Analysis of a Thaumasia Planum rift through automatic mapping and strain characterization of normal faults. Planetary and Space Science, 59(11-12), 1210–1221. doi:10.1016/j.pss.2010.07.008 .</li> <li>Vaz, D. A., Spagnuolo, M. G., & Silvestro, S. (2014). Morphometric and geometric characterization of normal faults on Mars. Earth and Planetary Science Letters, 401, 83–94. doi:10.1016/j.epsl.2014.05.022.</li> <li>Kinczyk, M. J., Prockter, L., Byrne, P., Denevi, B., Buczkowski, D., Ostrach, L., & Miller, E. (2019, September). The First Global Geological Map of Mercury. In <em>EPSC-DPS Joint Meeting 2019</em> (Vol. 2019, pp. EPSC-DPS2019).</li> </ul>

scholarly journals Characterization of the Particle Emission from Ships Operating at Sea Using Unmanned Aerial Vehicles

2017 ◽  
Author(s):  
Tommaso F. Villa ◽  
Reece Brown ◽  
E. Rohan Jayaratne ◽  
L. Felipe Gonzalez ◽  
Lidia Morawska ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Co2 Concentration ◽  
Emission Factors ◽  
Barrier Reef ◽  
Ship Emissions ◽  
Optimal Position ◽  
Exhaust Plume ◽  
Aerial Vehicle ◽  
First Time

Abstract. This research demonstrates the use of an unmanned aerial vehicle (UAV) to characterize the gaseous (CO2) and particle (10–500 nm) emissions of a ship at sea. The field study was part of the research voyage The Great Barrier Reef as a significant source of climatically relevant aerosol particles on-board the RV Investigator around the Australian Great Barrier Reef. Measurements of the RV Investigator exhaust plume were carried out while the ship was operating at sea, at a steady engine load of 30 %. The UAV system was flown autonomously using several different programmed paths. These incorporated different altitudes and distances behind the ship in order to investigate the optimal position to capture the ship plume. Five flights were performed, providing a total of 27 horizontal transects perpendicular to the ship exhaust plume. Results show that the most appropriate altitude and distance to effectively capture the plume was 25 m above sea level and 20 m downwind. Particle number (PN) emission factors (EF) were calculated in terms of number of particles emitted (#) per weight of fuel consumed (Kg fuel). Fuel consumption was calculated using the simultaneous measurements of plume CO2 concentration. Calculated EFPN were between 9.19 × 1014 and 5.15 × 1015 #∙(Kg fuel)−1. These values are in line with those reported in the literature for ship emissions ranging from 0.2 6.2 × 1016 #∙(Kg fuel)−1 to 6.2 × 1016 #∙(Kg fuel)−1. This UAV system successfully assessed ship emissions to derive emission factors (EFs) under real world conditions. This is significant as, for the first time, it provides a reliable, inexpensive and accessible way to assess and potentially regulate ship emissions.

Mineralogical and Geochemical Characterization of Mine Tailings and Pb, Zn, and Cd Mobility in a Carbonate Setting (Northern Tunisia)

2012 ◽  
Vol 32 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Radhia Souissi ◽  
Fouad Souissi ◽  
Hédi Karim Chakroun ◽  
Jean Luc Bouchardon
Keyword(s):  
Mine Tailings ◽  
Northern Tunisia ◽  
Geochemical Characterization

scholarly journals Modelling the 2012 Lahar in a Sector of Jamapa Gorge (Pico de Orizaba Volcano, Mexico) Using RAMMS and Tree-Ring Evidence

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 333 ◽  
Author(s):  
Osvaldo Franco-Ramos ◽  
Juan Antonio Ballesteros-Cánovas ◽  
José Ernesto Figueroa-García ◽  
Lorenzo Vázquez-Selem ◽  
Markus Stoffel ◽  
...  
Keyword(s):  
Mass Movement ◽  
Digital Terrain Model ◽  
Added Value ◽  
Terrain Model ◽  
Digital Terrain ◽  
Field Evidence ◽  
Pico De Orizaba Volcano ◽  
Reduction Strategies ◽  
Aerial Vehicle ◽  
Risk Reduction Strategies

A good understanding of the frequency and magnitude of lahars is essential for the assessment of torrential hazards in volcanic terrains. In many instances, however, data on past events is scarce or incomplete, such that the evaluation of possible future risks and/or the planning of adequate countermeasures can only be done with rather limited certainty. In this paper, we present a multiidisciplinary approach based on botanical field evidence and the numerical modelling of a post-eruptive lahar that occurred in 2012 on the northern slope of the Pico de Orizaba volcano, Mexico, with the aim of reconstructing the magnitude of the event. To this end, we used the debris-flow module of the rapid mass movement simulation tool RAMMS on a highly resolved digital terrain model obtained with an unmanned aerial vehicle. The modelling was calibrated with scars found in 19 Pinus hartwegii trees that served as paleo stage indicators (PSI) of lahar magnitude in a sector of Jamapa Gorge. Using this combined assessment and calibration of RAMMS, we obtain a peak discharge of 78 m3 s−1 for the 2012 lahar event which was likely triggered by torrential rainfall during hurricane “Ernesto”. Results also show that the deviation between the modelled lahar stage (depth) and the height of PSI in trees was up to ±0.43 m. We conclude that the combination of PSI and models can be successfully used on (subtropical) volcanoes to assess the frequency, and even more so to calibrate the magnitude of lahars. The added value of the approach is particularly obvious in catchments with very scarce or no hydrological data at all and could thus also be employed for the dating and modelling of older lahars. As such, the approach and the results obtained can be used directly to support disaster risk reduction strategies at Pico de Orizaba volcano, but also in other volcanic regions.

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