On the Use of Tri-Stereo Pleiades Images for the Morphometric Measurement of Dolines in the Basaltic Plateau of Azrou (Middle Atlas, Morocco)

Maria Teresa Melis,Jo De Waele,Luca Pisani

doi:10.3390/rs13204087

Maria Teresa Melis, Jo De Waele + Show 1 more

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https://doi.org/10.3390/rs13204087

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Journal: Remote Sensing	Publication Date: Oct 13, 2021
Citations: 9	License type: CC BY 4.0

Affiliation: University of Bologna, University of Cagliari

Abstract

Hundreds of large and deep collapse dolines dot the surface of the Quaternary basaltic plateau of Azrou, in the Middle Atlas of Morocco. In the absence of detailed topographic maps, the morphometric study of such a large number of features requires the use of remote sensing techniques. We present the processing, extraction, and validation of depth measurements of 89 dolines using tri-stereo Pleiades images acquired in 2018–2019 (the European Space Agency (ESA) © CNES 2018, distributed by Airbus DS). Satellite image-derived DEMs were field-verified using traditional mapping techniques, which showed a very good agreement between field and remote sensing measures. The high resolution of these tri-stereo images allowed to automatically generate accurate morphometric datasets not only regarding the planimetric parameters of the dolines (diameters, contours, orientation of long axes), but also for what concerns their depth and altimetric profiles. Our study demonstrates the potential of using these types of images on rugged morphologies and for the measurement of steep depressions, where traditional remote sensing techniques may be hindered by shadow zones and blind portions. Tri-stereo images might also be suitable for the measurement of deep and steep depressions (skylights and collapses) on Martian and Lunar lava flows, suitable targets for future planetary cave exploration.

Highlights

Geological landscapes and structures can be studied starting from high spatial resolution Digital Elevation Models (DEMs) and a set of useful tools able to extract specific landforms and quantify geomorphological parameters [1,2,3]
Studies based on the comparison between DEM and fieldbased data have demonstrated that the use of digital images with an appropriate spatial resolution generally provides reliable results in the morphometric characterization of sinkholes [11,12]
The possible presence of well-developed karst systems, covered by basalts but reactivated after the emplacement of these volcanic rocks, should be taken into account when considering the vulnerability of this significant regional aquifer, with important karst springs used for drinking water purposes (e.g., Oum Er-Rbia) [26,27]

Summary

Introduction

Geological landscapes and structures can be studied starting from high spatial resolution Digital Elevation Models (DEMs) and a set of useful tools able to extract specific landforms and quantify geomorphological parameters [1,2,3]. Topographical maps of sufficient scale and precision are often not available for many regions in the world. In these areas, the combination of remote sensing data from different sources into. Studies based on the comparison between DEM and fieldbased data have demonstrated that the use of digital images with an appropriate spatial resolution generally provides reliable results in the morphometric characterization of sinkholes [11,12].

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