Spatial analysis of a critical slope instability area through multitemporal UAV photogrammetry

Recent years have seen a rapid worldwide rise in the vulnerability to natural hazards that affect humans. Inadequate government regulations and ineffective implementation of territorial planning policies result in frequent construction of buildings in marginal and high-risk areas to natural hazards. One of these wrong decisions is the expansion of semi-urban settlements in areas susceptible to slope failure. In the present study, geomatic approaches to assess volumetric and topography changes over time were implemented in an area of critical slope instability at the northwest outskirts of the city of Urcuquí, Ecuador. The methodology applied allowed recording spatial changes in the soil surface topography over an area of approximately 0.171 km2 over a period of ~6 months (October 2020 to March 2021). The main equipment used to acquire the data was a DJI Inspire 2 unmanned aerial vehicle. From the aerial photogrammetry data processed with Structure from Motion software Pix4D Mapper dense point clouds at high resolution (0.5 to 4 cm/pixel) were generated, which were our data base for the development of the study. Our results from spatial analysis show that the slope undergoes a continuous change during the period of study. Results of the C2M and M3C2 comparisons in Cloud Compare software show critical regions of constant movement and slope failure in the two sides of the Pinchinguela ravine in which the study was developed. However, it is not possible to reach the resolution of millimeters which was obtained to describe the 3D vectors motion obtained from ground control points data by traditional topographic surveys with Trimble Total Station S5. Even though the identified slope instability area showed specific sections of slope failure and displacements, it can result in a catastrophic event if the Municipal Autonomous Decentralized Government of San Miguel of Urcuquí does not apply any kind of planning and territorial measurements to mitigate this hazard. Finally, the methodology of this study can be used to risk detection of any type of mass movements as well as land use planning in semi-urban settlements in Ecuador and the rest of the world.

• मुख्य लेखक: Rivadeneira Aguirre, Anderson Patricio (author)
• स्वरूप: bachelorThesis
• भाषा: eng
• प्रकाशित: 2021
• विषय: Vulnerabilidad; Asentamientos semiurbanos; Pendientes inestables; Fotogrametría aérea; Método de detección de riesgos; Vulnerability; Semi-urban settlements; Slope instability areas; Aerial photogrammetry technique; Risk detection method
• ऑनलाइन पहुंच: http://repositorio.yachaytech.edu.ec/handle/123456789/553