Integration of LiDAR data for the assessment of activity in diachronic landslides: a case study in the Betic Cordillera (Spain)

• Published in: Landslides Vol. 13; no. 4; pp. 629 - 642
• Main Authors: Palenzuela, J. A., Jiménez-Perálvarez, J. D., El Hamdouni, R., Alameda-Hernández, P., Chacón, J., Irigaray, C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2016; Springer Nature B.V
• Subjects: Activation; Agriculture; Civil Engineering; Data analysis; Data processing; Digital; Earth and Environmental Science; Earth Sciences; Geography; Geophysics; Landslides; Landslides & mudslides; Lidar; Methodology; Natural Hazards; Original Paper; Remote sensing systems; Risk assessment; Scanning; Terrain; Thresholds; Spain; Spain, Andalucia, Betic Cordilleras; Laser scanner; Betic Cordillera; Ground movement; Landslide activity; LiDAR
• ISSN: 1612-510X; 1612-5118
• DOI: 10.1007/s10346-015-0598-x

In the procedures to minimize diachronic landslides, data on their temporal evolution and destructive capacities are necessary. For that purpose, remote-detection techniques proved to be highly useful for quantifying the ongoing change in the relief, as well as in comparisons between digital terrain models achieved by Light Detection and Ranging. The methodology presented in this paper includes the supervised merging and comparison of sequential scans, acquired within nearly annual intervals from an irregular terrain, which improves the quality of the results highlighting ground changes. This approach is based on the processing of digital terrain models from point clouds acquired by Terrestrial Laser Scanning to quantify and interpret the landslide displacements. In parallel, it is supported by Global Navigation Satellite Systems, the use of artificial targets and a refined data processing to minimize the uncertainty and improve the precision of the results. This is applied to a large translational slide affecting phyllite rocks in a IV-V degree of weathering settled on the southern slope of Sierra Nevada (south-eastern Spain). During the monitoring period (2008–2010), the slide remained inactive until 2009, followed by a reactivation with displacements in the range −1.80 to 1.20 m along the period 2009–2010, where negative values are downwards from the reference model (2009). The accumulated relative standard deviation between data sets was on the order of 7.5 cm, whereas the threshold to determine a terrain displacement (also avoiding changes due to erosion-accumulation processes) was of 10 cm. When applying this methodology to Airborne Laser Scanning datasets for the years 2008 and 2010, covering zones hidden to the line of sight of the terrestrial technique, a reactivation with similar deformation pattern was found useful to validate the findings, although the detail of changes and quantitative results did not match exactly due to the different accuracy and resolution of both techniques. The reactivation of the slide coincided with a period of intense rains, pointing to this as the triggering factor, with a precipitation threshold of roughly 1000 mm in a period of 4 months, only reached on one occasion throughout in the historical record.