Assessment of the Evolution of a Landslide Using Digital Photogrammetry and LiDAR Techniques in the Alpujarras Region (Granada, Southeastern Spain)

Abstract

Abstract:In this work a detailed analysis of the temporal evolution of the Almegíjar landslide is presented. It is a rock slide located in the Alpujarras region (Granada, Spain) that has developed over the last 30 years. Six datasets and photogrammetric flights corresponding to the years 1956, 1984, 1992, 2001, 2008, and 2010 were surveyed. The more recent flight of 2010 combined an aerial digital camera and a LiDAR sensor and was oriented by means of in-flight data and tie points. This 2010 flight allowed for the generation of a reliable and high-precision Digital Terrain Model (DTM). The other flights were oriented using second-order ground control points transferred from the 2010 flight, and the corresponding DTMs were prepared by automatic matching and subsequent editing from the stereoscopic models. After comparing the DTMs of different dates, it has been observed that the landslide was triggered after 1984 and since then has evolved in an irregular pattern with periods of variable activity. On average, the ground surface dropped more than 8 m in depleted zones and rose nearly 4 m in the accumulation zones, with a velocity catalogued as very slow (about 15-30 cm/year) over a time span corresponding to a degree VIII of diachroneity. The total volume of the mobilized mass of this large contemporary slide was about 300 × 10 3 m 3 .

Measurement of Road Surface Deformation Using Images Captured from UAVs

“…The methodology was based on aerial photogrammetry techniques used in previous landslide monitoring studies by the authors [7,16,41,42,49,69]. Such methodologies were adapted to the case study analyzed in this paper since some boundary conditions had to be taken into consideration.…”

“…Data capture is currently done by means of several instruments and techniques that according to [2] can be classified in: satellite and remote sensing techniques, from optical spectrum to DInSAR approaches [3][4][5]; aerial photogrammetric and LiDAR techniques [6,7]; geodetic and surveying techniques [8,9]; and geotechnical and geophysical techniques [10]. The first two groups can be considered as remote sensing techniques and the last two groups as in situ techniques.…”

Observing Geohazards from Space

“…Going back to similar historical times, Fernández et al [5] use a 54-year long multi-temporal set of photogrammetric flights for the generation of Digital Terrain Models (DTM) to analyse the evolution of the Almegíjar rock slide in Spain. The authors exploit an aerial digital camera with four spectral bands (i.e., visible RGB, and near-infrared NIR), a Light Detection and Ranging (LiDAR) sensor, and in-flight orientation based on Global Navigation Satellite System (GNSS) onboard a 2010 flight to generate a high-precision DTM that they then use as a reference for comparison with other elevation models generated based on historical panchromatic flights.…”

Identification and Extraction of Geomorphological Features of Landslides Using Slope Units for Landslide Analysis

“…It can rapidly acquire high-precision terrestrial 3D models and can be applied to landslide identification, dynamic landslide deformation monitoring and acquisition of geomorphological features [31,32]. The LiDAR system is composed of a 3D laser scanning system, a control system and a power supply system [33][34][35][36]. The complete 3D laser scanning system includes a laser ranging and angle measuring system, a laser scanning system, an integrated charge-coupled device camera, and an internal control and correction system.…”