This research tests the application of GNSS and RPAS techniques to the spatiotemporal analysis of landslide dynamics. Our method began by establishing non-permanent GNSS networks on the slope surfaces to perform periodic measurements by differential GNSS. Similarly, RPAS flights were made to acquire high-resolution images, which were oriented and georeferenced using ground control points and structure-from-motion algorithms to ultimately obtain digital surface models and orthophotos. Based on GNSS measurements, the direction and velocity of displacements were accurately calculated, and orthophotos and DSMs were used to calculate horizontal and vertical displacements in a set of significant points throughout the study area, reaching accuracies higher than 0.035 m in the GNSS data and 0.10 m in the RPAS data. These values were within the accuracy required for such studies. Based on the field observations and the results from the photogrammetric studies, the two studied landslides were classified as very slow flows. These techniques are the basis for establishing early warning systems in areas of natural hazards based on the calculation of displacement speeds of the surface of slopes.

This case study focuses on the area of El Plateado near the city of Loja, Ecuador, where landslides with a high impact on infrastructures require monitoring and control. The main objectives of this work are the characterization of the landslide and the monitoring of its kinematics. Four flights were conducted using a remotely piloted aerial vehicle (RPAS) to capture aerial images that were processed with SfM techniques to generate digital elevation models (DEMs) and orthoimages of high resolution (0.05 m) and sufficient accuracy (below 0.05 m) for subsequent analyses. Thus, the DEM of differences (DoD) and profiles are obtained, but a morphometric analysis is conducted to quantitatively characterize the landslide’s elements and study its evolution. Parameters such as slope, aspect, topographic position index (TPI), terrain roughness index (TRI), and topographic wetness index (TWI) are analyzed. The results show a higher slope and roughness for scarps compared to stable areas and other elements. From TPI, slope break lines have been extracted, which allow the identification of landslide features such as scarps and toe tip. The landslide shows important changes in the landslide body surface, the retraction of the main scarp, and advances of the foot. A general decrease in average slope and TRI and an increase in TWI are also observed due to the landslide evolution and stabilization. The presence of fissures and the infiltration of rainfall water in the unsaturated soil layers, which consist of high-plasticity clays and silts, contribute to the instability. Thus, the study provides insights into the measurement accuracy, identification and characterization of landslide elements, morphometric analysis, landslide evolution, and the relationship with geotechnical factors that contribute to a better understanding of landslides. A higher frequency of the RPAS surveys and quality of geotechnical and meteorological data are required to improve the instability analysis together with a major automation of the GIS procedures.

No abstract

El objetivo de esta investigación es analizar la influencia de las restricciones del tránsito vehicular sobre el número de contagios y fallecimientos por el COVID-19 en una ciudad al sur del Ecuador. Se analizó el tránsito de ingreso y salida a la ciudad, las leyes gubernamentales y las tendencias del COVID-19 en la zona de estudio. Como resultado, las restricciones del tránsito vehicular influyeron sobre el número de contagios semanales, así como los fallecimientos semanales por el coronavirus. This study aims to analyze the impact of vehicular traffic restrictions on the number of infections and deaths by COVID-19 in a city in southern Ecuador. Traffic into and out of the city, government laws, and COVID-19 trends in the study area were analyzed. As a result, vehicle traffic restrictions influenced the number of weekly infections, as well as weekly deaths from the coronavirus. Este estudo tem como objetivo analisar o impacto das restrições de tráfego de veículos no número de infecções e mortes por COVID-19 em uma cidade no sul do Equador. Foram analisados ​​o tráfego de entrada e saída da cidade, as leis do governo e as tendências do COVID-19 na área de estudo. Como resultado, as restrições de tráfego de veículos influenciaram o número de infecções semanais, bem como as mortes semanais pelo coronavírus.

El objetivo de este estudio fue evaluar las fallas superficiales presentes en un pavimento flexible de aproximadamente 500 m de longitud mediante el uso de VANT y demostrar la capacidad de las imágenes capturadas. La investigación es de tipo aplicada tecnológica y el enfoque que se utilizó fue cuantitativo. La metodología se centró en tres etapas: inicialmente, la planificación de la zona de estudio, luego la recolección y procesamiento de datos, para culminar con el análisis de resultados. La muestra de estudio fue aleatoria, con 13 tipos de baches y fisuras sobre el pavimento. Los datos se obtuvieron a una elevación de 40 m capturando imágenes cada 2 s. El procesamiento se hizo a través de un software fotogramétrico basado en el algoritmo SfM. Como resultado, se aprecia que la diferencia entre las mediciones visuales y las obtenidas por SIG oscila entre 0,17 y 5 cm. La desviación estándar del conjunto de muestras fue de 2,32 cm. Se demostró la capacidad de la imagen capturada con VANT para la extracción de distintas fallas superficiales. Este sistema proporciona una medición detallada y precisa de la ruta de la carretera y de la geometría del bache, y, por lo tanto, mejora la eficiencia del monitoreo del estado de la carretera.