Antonio Abellan

Centre de Recherche sur l´Environnement Alpin | CREALP · Research Center on Alpine Environment

This Special Issue contains a collection of articles discussing the use of three-dimensional remote sensing techniques for the investigation diverse geo-hazards. We received a total of 13 manuscripts for consideration, which were thoughtfully reviewed by external experts in their respective fields. In addition, the Guest Editors of this Special Iss...

Ground-based LiDAR has been traditionally used for surveying purposes via 3D point clouds. In addition to XYZ coordinates, an intensity value is also recorded by LiDAR devices. The intensity of the backscattered signal can be a significant source of information for various applications in geosciences. Previous attempts to account for the scattering...

This study presents a point cloud de-noising and calibration approach that takes advantage of point redundancy in both space and time (4D). The purpose is to detect displacements using terrestrial laser scanner data at the sub-mm scale or smaller, similar to radar systems, for the study of very small natural changes, i.e., pre-failure deformation i...

Rock mass characterization requires a deep geometric understanding of the discontinuity sets affecting rock exposures. Recent advances in Light Detection and Ranging (LiDAR) instrumentation currently allow quick and accurate 3D data acquisition, yielding on the development of new methodologies for the automatic characterization of rock mass discont...

This manuscript presents a review on the application of a remote sensing technique (Terrestrial Laser Scanning, TLS) to a well-known topic (rock slope characterization and monitoring). Although the number of publications on the use of TLS in rock slope studies has rapidly increased in the last 5-10 years, little effort has been made in reviewing th...

Change-detection monitoring plays a crucial role in geoscience, facilitating the examination of earth surface processes and the mitigation of potential risks due to natural hazards. A significant aspect of this monitoring involves the use of images, enabling 2D to 4D monitoring approaches. Our objective is to bridge the knowledge gap in developing...

In this publication we address the lack of technical expertise in the geoscience community in the design and construction of photogrammetric systems for monitoring natural hazards at high spatio-temporal resolution. Accordingly, we provide in-depth information on the components, assembly instructions, and programming codes required to build them, m...

Change-detection monitoring plays a crucial role in the field of geoscience, enabling the study of various natural phenomena and, ultimately, the mitigation of their potential impacts. Currently, a significant part of this monitoring utilizes 3D models generated from images using structure-from-motion algorithms. However, the growing importance of...

In this publication we address the lack of knowledge in the design and construction of photogrammetric systems for high spatio-temporal resolution rockfall monitoring. Accordingly, we provide in-depth information on the components, assembly instructions, and programming codes required to build them, making them accessible to researchers from differ...

In recent years, photogrammetric models have gained widespread use in geosciences due to their ability to reproduce natural surfaces. These models offer a cost-effective and user-friendly alternative to other systems, such as LiDAR, for creating 3D point clouds. On the other hand, rockfalls pose a significant risk to society, as they are the most c...

The purpose of this communication is to show the results obtained in a doctoral thesis based on the development of new algorithms and time-lapse photogrammetric systems for automatic rockfall monitoring that were tested on two active slopes in different geographical environments. On the one hand, a very cost-efficient photogrammetric system using R...

Presentación del proyecto RESCUhE en las I Jornadas Científico-Técnicas del CN IGME-CSIC

This paper is based on the fact that some climatic variables show a preferential directionality and grant a markedly anisotropic character to the weathering system acting on rocks. The aim of this work is to quantify the anisotropic degree of the weathering system and its effects on rock erosion. For this purpose, a new methodology based on the vec...

Monitoring the evolution of natural slopes with 3D data is a key strategy for detecting and investigating rockfalls (Abellan et al, 2016). In order to improve our understanding of rock slope failures and to reduce the associated risk, different monitoring strategies have been developed during the last decade using LiDAR, allowing the study of the s...

Using photogrammetric techniques for 3D modelling of natural surfaces has increased significantly in recent years (Eltner, et al. 2016). The easiness of obtaining photographs in an automated way, as well as the low cost of the whole photogrammetric system ensures a great usability when compared to LiDAR point clouds. Currently, there are different...

Calving and solid ice discharge into fjords account for approximately half of the annual net ice loss from the Greenland ice sheet, but these processes are rarely observed. To gain insights into the spatiotemporal nature of calving, we use a terrestrial radar interferometer to derive a 3‐week record of 8,026 calving events from Sermeq Kujalleq (Sto...

Photogrammetric models have become a standard tool for the study of surfaces, structures and natural elements. As an alternative to Light Detection and Ranging (LiDAR), photogrammetry allows 3D point clouds to be obtained at a much lower cost. This paper presents an enhanced workflow for image-based 3D reconstruction of high-resolution models desig...

The use of 3D point clouds to improve the understanding of natural phenomena is currently applied in natural hazard investigations, including the quantification of rockfall activity. However, 3D point cloud treatment is typically accomplished using nondedicated (and not optimal) software. To fill this gap, we present an open-source, specific rockfa...

On September 5, 2019, the Veslemannen unstable rock slope (54,000 m ³ ) in Romsdalen, Western Norway, failed catastrophically after 5 years of continuous monitoring. During this period, the rock slope weakened while the precursor movements increased progressively, in particular from 2017. Measured displacement prior to the failure was around 19 m i...

A growing body of research indicates that rock slope failures, particularly from exfoliating cliffs, are promoted by rock deformations induced by daily temperature cycles. Although previous research has described how these deformations occur, full three-dimensional monitoring of both the deformations and the associated temperature changes has not y...

The emerging use of photogrammetric point clouds in three-dimensional (3D) monitoring processes has revealed some constraints with respect to the use of LiDAR point clouds. Oftentimes, point clouds (PC) obtained by time-lapse photogrammetry have lower density and precision, especially when Ground Control Points (GCPs) are not available or the camer...

Calving and solid ice discharge into fjords account for approximately half of the annual net ice loss from the Greenland Ice Sheet, but these processes are rarely observed. To gain insights into the spatio-temporal nature of calving, we use a terrestrial radar interferometer to derive a three-week record of 8,026 calving events from Store Glacier,...

Monitoring rock slope failures in natural environments using LiDAR has considerably increased our understanding of rockfall phenomena during the last decade, but the economic and logistic costs associated with the instrument and data acquisition has considerably limited our ability to increase the frequency of monitoring campaigns, especially in re...

Unmanned aerial vehicles (UAVs) and structure from motion with multi-view stereo (SfM–MVS) photogrammetry are increasingly common tools for geoscience applications, but final product accuracy can be significantly diminished in the absence of a dense and well-distributed network of ground control points (GCPs). This is problematic in inaccessible or...

Unmanned Aerial Vehicles (UAVs) and Structure from Motion with Multi-View Stereo (SfM-MVS) photogrammetry are increasingly common tools for geoscience applications, but final product accuracy can be significantly diminished in the absence of a dense and well-distributed network of ground control points (GCPs). This is problematic in inaccessible or...

Finding new ways to quantify discontinuity persistence values in rock masses in an automatic or semi-automatic manner is a considerable challenge, as an alternative to the use of traditional methods based on measuring patches or traces with tapes. Remote sensing techniques potentially provide new ways of analysing visible data from the rock mass. T...

Along many Mediterranean coasts, the detached seagrass material of Posidonia oceanica creates seagrass berms that control the structure and morphodynamics of sandy beaches. Here, we show how Terrestrial Laser Scanner remote sensing data allows analyzing the 3-D morphologic change of beaches where this characteristic geomorphic structure is present....

The detached seagrass material of Posidonia oceanica conforms characteristics beach-cast accumulations (banquettes) which predetermine the structure and morphodynamics of the sandy beaches in many Mediterranean coasts (Vacchi et al., 2016). The aim of this contribution is to examine the evolution of a microtidal pocket-beach with these characterist...

The continuous improvement of the remote sensing techniques is having a considerable impact on the characterization and monitoring of rock slopes. Rock slope characterization can be conducted by analysing the coordinates of the points or the mesh derived from point clouds. Previous works on rock slope characterization using 3D point clouds have foc...

The continuous improvement of remote sensing techniques is having a considerable impact on the characterization and monitoring of rock slopes. Rock slope characterization can be conducted by analysing the coordinates of the points or the mesh derived from point clouds. Previous works on rock slope characterization using 3D point clouds have focused...

Discontinuities play a key role in the mechanical, hydraulic and deformational behaviour of rock masses, frequently having a considerable influence on the stability of rock slopes. They can be characterized by several geometric parameters as the orientation, persistence, spacing, etc. Although orientation has been traditionally measured through wel...

We discuss here different challenges and limitations of surveying rock slope failures using 3-D reconstruction from image sets acquired from street view imagery (SVI). We show how rock slope surveying can be performed using two or more image sets using online imagery with photographs from the same site but acquired at different instances. Three sit...

Terrestrial laser scanning (TLS) monitoring has been used to estimate the location, volume, and kinematics of a variety of small magnitude rockfalls before failure (1-1000 m 3 range), and in some cases, potential failure time has been assessed through the application of inverse velocity methods. However, our current understanding of rock slope pre-...

Los arribazones de Posidonia oceanica se acumulan en las playas del mar Mediterráneo, formando una barrera protectora entre la interfase mar-tierra. Dicha barrera protege a la playa de la pérdida de arena, suponiendo un aporte de nutrientes al complejo arenoso y permitiendo la estructuración de la macrofauna de invertebrados, que encuentran aliment...

Posidonia oceanica “banquettes” accumulate on the beaches of the Mediterranean Sea, forming a protective barrier between the sea-land interface. This barrier protects the beach from the loss of sand, besides supposing a nutrient contribution to the sandy complex, allowing the structure of the macrofauna of coastal invertebrates, which in addition t...

Landslides are very complex processes controlled by multiple factors. The knowledge and characterization of these factors is essential for a comprehensive understanding of the mechanisms and kinematics of the instabilities and for an efficient design of corrective measures. The aim of this work is to combine traditional geological and geotechnical...

In June 2005, a series of major rockfall events completely wiped out the Bonatti Pillar located in the legendary Drus west face (Mont Blanc massif, France). Terrestrial lidar scans of the west face were acquired after this event, but no pre-event point cloud is available. Thus, in order to reconstruct the volume and the shape of the collapsed block...

El 6/04/2015 un desprendimiento en el vaso del embalse de Cortes de Pallás (Valencia) sepultó instalaciones de una central hidroeléctrica de Iberdrola dejando ocho meses incomunicada la población por carretera. Durante la emergencia, Iberdrola encargó un vuelo de reconocimiento del talud, aún inestable y peligroso, sin patrón específico. Sobre esta...

En el presente trabajo se recogen los resultados más significativos de la caracterización geológico-geotécnica y de la monitorización llevada en un talud afectado por procesos de erosión hídrica superficial y subsuperficial del término municipal de Elche (Alicante). El talud objeto de estudio se encuentra excavado en materiales limosos cubiertos po...

We present an automated terrestrial laser scanning (ATLS) system with automatic near-real-time change detection processing. The ATLS system was tested on the Séchilienne landslide in France for a 6-week period with data collected at 30 min intervals. The purpose of developing the system was to fill the gap of high-temporal-resolution TLS monitoring...

We present an automated terrestrial laser scanning (ATLS) system with automatic near-real-time change detection processing. The ATLS system was tested on the Séchilienne landslide in France for a 6-week period with data collected at 30 min intervals. The purpose of developing the system was to fill the gap of high-temporal-resolution TLS monitoring...

Recent advances are made in earth surface reconstruction with high spatial resolution due to SfM photogrammetry. High flexibility of data acquisition and high potential of process automation furthermore allows for a significant increase of the temporal resolution, which is especially interesting to assess geomorphic changes. Two case studies are pr...

Cliff erosion may be a major problem in settled areas affecting populations and producing economic and ecological losses. In this paper we present a procedure to calculate the long-term retreat rate of a cliff affected by rockfalls in the Montsec Range, Eastern Pyrenees (Spain). It is composed of low, densely fractured limestones; and the rockwall...

We discuss here the challenges and limitations on surveying rock slope failures using 3D reconstruction from images acquired from Street View Imagery (SVI) and processed with modern photogrammetric workflows. We show how the back in time function can be used for a 3D reconstruction of two or more image sets from the same site but at different insta...

Capturing and quantifying the world in three dimensions (x,y,z) using light detection and ranging (lidar) technology drives fundamental advances in the Earth and Ecological Sciences (EES). However, additional lidar dimensions offer the possibility to transcend basic 3-D mapping capabilities, including i) the physical time (t) dimension from repeat...

This short note presents an approach to assess rockfall susceptibility based on terrestrial laser scanner (TLS) point cloud data at the cliff scale. The test area is coastal cliff situated in the southern part of the Campania Region (Centola Municipality, SW Italy), in which a natural arch was formed. Since this coastal area constitutes an importan...

New 3D data acquisition techniques allow to obtain geometrical information of exposed rock masses. This information can be used to characterize some geo-mechanical parameters of rock slopes, allowing users to remotely obtain information. Recently, many researchers have been working on the extraction of geomechanical parameters of rock masses using...

La técnica Structure from Motion (SfM) es considerada como un método fotogramétrico automatizado de alta resolución y bajo coste en relación a otras técnicas. Este método se basa en los mismos principios que la fotogrametría estereoscópica clásica, es decir, que la estructura en 3D se puede resolver a partir de una superposición de imágenes ópticas...

La evaluación de la estabilidad de un macizo rocoso requiere la obtención de parámetros físicos, mecánicos y geométricos. Ciertas propiedades geométricas pueden ser estudiadas sin necesidad de acceder al talud si se dispone de información de su superficie. Esto es posible gracias a las técnicas de adquisición remota (ej. LiOAR y fotogrametría), las...

In June 2005, a series of major rockfall events completely wiped out the Bonatti Pillar located in the legendary Drus West face (Mont-Blanc massif, France). Terrestrial LiDAR scans of the face were acquired after this event but no pre-event point cloud is available. Thus, in order to reconstruct the volume and the shape of the collapsed blocks, a 3...

Rock avalanches are extremely destructive and uncontrollable events that involve a great volume of material (> 10⁶ m³) and several complex processes, and they are difficult to witness. For this reason the study of these phenomena using analog modeling and the accurate analysis of deposit structures and features of laboratory data and historic event...

Rockfall activity in Yosemite Valley is often linked to the presence of sheeting joints (i.e., fractures separating exfoliation sheets), parallel to the topography and ubiquitous throughout the valley (Martel, 2011). The Yosemite rockfall database (Stock et al., 2013) shows that many historical events occurred without recognized triggers, during wa...

The Messinian coral reef (atoll type)of Santa Pola, placed in the northern sector of the Bajo Seguraneogene basin, is one of the most important places of geoscientist interest from Alicante Province. In this work, the characterization of its geological and paleontological heritage is presented. Firstly, the quantitative patrimonial evaluation is pr...

New 3D data acquisition techniques allow to obtain geometrical information of exposed rock masses. This information can be used to characterize some geo-mechanical parameters of rock slopes, allowing users to remotely obtain information. Recently, many researchers have been working on the extraction of geo-mechanical parameters of rock masses using...

Monitoring landslides with terrestrial laser scanning (TLS) is currently a well-known technique. One problem often encountered is the vegetation that produces shadow areas on the scans. Indeed, the points behind a given obstacle are hidden and thus occluded on the point cloud. Thereby, locations monitored with terrestrial laser scanner are mostly r...