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Department of Geography
University of Valladoli, Spain
Adrián Martínez-Fernández, Alfonso Benito-Calvo, Isidoro Campaña, Ana Isabel Ortega, Theodoros Karampaglidis, José María Bermúdez de Castro, and Eudald Carbonell
Digital Applications in Archaeology and Cultural Heritage, ISSN: 22120548, Published: December 2020 Elsevier BV
Enrique Serrano, José Juan Sanjosé‐Blasco, Manuel Gómez‐Lende, Juan Ignacio López‐Moreno, Alfonso Pisabarro, and Adrián Martínez‐Fernández
Permafrost and Periglacial Processes, ISSN: 10456740, eISSN: 10991530, Pages: 292-309, Published: 1 October 2019 Wiley
A. Martínez-Fernández, E. Serrano, J. J. Sanjosé, M. Gómez-Lende, A. Pisabarro, and M. Sánchez
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives, ISSN: 16821750, Issue: 2/W13, Pages: 1771-1775, Published: 4 June 2019 Copernicus GmbH
<p><strong>Abstract.</strong> Rock glaciers are one of the most important features of the mountain permafrost in the Pyrenees. La Paúl is an active rock glacier located in the north face of the Posets massif in the La Paúl glacier cirque (Spanish Pyrenees). This study presents the preliminary results of the La Paúl rock glacier monitoring works carried out through two geomatic technologies since 2013: Global Navigation Satellite System (GNSS) receivers and Terrestrial Laser Scanning (TLS) devices. Displacements measured on the rock glacier surface have demonstrated both the activity of the rock glacier and the utility of this equipment for the rock glaciers dynamic analysis. The glacier has exhibited the fastest displacements on its west side (over 35&thinsp;cm&thinsp;yr<sup>&minus;1</sup>), affected by the Little Ice Age, and frontal area (over 25&thinsp;cm&thinsp;yr<sup>&minus;1</sup>). As an indicator of permafrost in marginal environments and its peculiar morphology, La Paúl rock glacier encourages a more prolonged study and to the application of more geomatic techniques for its detailed analysis.</p>
Francisco Gutiérrez, Alfonso Benito-Calvo, Domingo Carbonel, Gloria Desir, Jorge Sevil, Jesús Guerrero, Adrián Martínez-Fernández, Theodoros Karamplaglidis, Ángel García-Arnay, and Ivan Fabregat
Engineering Geology, ISSN: 00137952, Volume: 248, Pages: 283-308, Published: 8 January 2019 Elsevier BV
Abstract The need to apply sinkhole remediation and monitoring programs is increasing, concurrently with the rising engineering impacts of sinkholes in many regions. However, there is a significant gap in the scientific literature regarding the assessment of the performance of remedial works through subsidence monitoring. Monitoring techniques have experienced significant advances in the last few years thanks to the advent of new technologies. This work presents a review of sinkhole monitoring methods and discusses some practical considerations about their capabilities and limitations. It also documents a monitoring program (high-precision leveling and terrestrial laser scanner) and the concurrent remedial works (cement-based and polyurethane grouting) carried out in a highly active sinkhole that affects a flood-control dike and the adjacent village of Alcala (NE Spain). The subsidence activity in the sinkhole is characterised by progressive sagging and the development of catastrophic nested collapses. Monitoring data reveal subsidence expansion and acceleration in the sector of the dike treated by polyurethane grouting above the main cavities. In contrast, subsequent cement-based grouting of the large cavities significantly reduced subsidence rates. Displacement data also indicate substantial subsidence enhancement following flood recession and the associated water table drop (buoyancy loss). This case study illustrates that high-precision leveling and terrestrial laser scanning are adequate complementary methods for monitoring specific sinkholes, characterised by very high accuracy and detailed spatial resolution, respectively.
Alfonso Benito-Calvo, Alyssa N. Crittenden, Sarah V. Livengood, Laura Sánchez-Romero, Adrián Martínez-Fernández, Ignacio de la Torre, and Michael Pante
Journal of Archaeological Science: Reports, ISSN: 2352409X, Pages: 611-621, Published: August 2018 Elsevier BV
Surface morphometry comprises a relevant set of techniques that provide objective tools to identify, map, and understand use wear patterns in stone tools. Thus far, these techniques have been applied mainly to 2D or 2.5D data, but their application to 3D 360° data is promising and still underdeveloped. Here, we apply new 3D techniques to calculate morphometric variables and to analyse surficial features and changes in pounding stone tools used for baobab processing among Hadza foragers of Tanzania. Baobab pounding stones were collected after use by Hadza foragers for processing the plant food and then 3D point clouds were acquired from laser scanners and SfM photogrammetry. Morphometry was conducted directly on 3D point clouds to avoid time-consuming and surface modifications related to more complex 3D data, such as meshing. Several morphometric variables were computed for the complete pieces (360° sphere) providing fast and accurate data to identify the detailed morphometric features of the artefacts. Additionally, stone surface changes due to baobab processing were measured by comparing the stone surface before and after use, thus enabling calculation of spatial abrasion patterns. Data were interpreted using multivariate exploratory statistical analysis. Differences in the effect of processing on surface morphology are likely explained by variations in raw source material and use. Results suggest that the traces produced by baobab processing on stone tools should be detectable in the archaeological record.
Alfonso Benito-Calvo, Francisco Gutiérrez, Adrián Martínez-Fernández, Domingo Carbonel, Theodoros Karampaglidis, Gloria Desir, Jorge Sevil, Jesús Guerrero, Ivan Fabregat, and Ángel García-Arnay
Remote Sensing, eISSN: 20724292, Published: 1 April 2018 MDPI AG
This work explores, for the first time, the application of a Terrestrial Laser Scanner (TLS) and a comparison of point clouds in the 4D monitoring of active sinkholes. The approach is tested in three highly-active sinkholes related to the dissolution of salt-bearing evaporites overlain by unconsolidated alluvium. The sinkholes are located in urbanized areas and have caused severe damage to critical infrastructure (flood-control dike, a major highway). The 3D displacement models derived from the comparison of point clouds with exceptionally high spatial resolution allow complex spatial and temporal subsidence patterns within one of the sinkholes to be resolved. Detected changes in the subsidence activity (e.g., sinkhole expansion, translation of the maximum subsidence zone, development of incipient secondary collapses) are related to potential controlling factors such as floods, water table changes or remedial measures. In contrast, with detailed mapping and high-precision leveling, the displacement models, covering a relatively short time span of around 6 months, do not capture the subtle subsidence (<0.6–1 cm) that affects the marginal zones of the sinkholes, precluding precise mapping of the edges of the subsidence areas. However, the performance of TLS can be adversely affected by some methodological limitations and local conditions: (1) limited accuracy in large investigation areas that require the acquisition of a high number of scans, increasing the registration error; (2) surface changes unrelated to sinkhole activity (e.g., vegetation, loose material); (3) traffic-related vibrations and wind blast that affect the stability of the scanner.