Spaceborne, UAV and ground-based remote sensing techniques for landslide mapping, monitoring and early warning

Abstract

Background: The current availability of advanced remote sensing technologies in the field of landslide analysis allows for rapid and easily updatable data acquisitions, improving the traditional capabilities of detection, mapping and monitoring, as well as optimizing fieldwork and investigating hazardous or inaccessible areas, while granting at the same time the safety of the operators. Among Earth Observation (EO) techniques in the last decades optical Very High Resolution (VHR) and Synthetic Aperture Radar (SAR) imagery represent very effective tools for these implementations, since very high spatial resolution can be obtained by means of optical systems, and by the new generations of sensors designed for interferometric applications. Although these spaceborne platforms have revisiting times of few days they still cannot match the spatial detail or time resolution achievable by means of Unmanned Aerial Vehicles (UAV) Digital Photogrammetry (DP), and ground-based devices, such as Ground-Based Interferometric SAR (GB-InSAR), Terrestrial Laser Scanning (TLS) and InfraRed Thermography (IRT), which in the recent years have undergone a significant increase of usage, thanks to their technological development and data quality improvement, fast measurement and processing times, portability and cost-effectiveness. In this paper the potential of the abovementioned techniques and the effectiveness of their synergic use is explored in the field of landslide analysis by analyzing various case studies, characterized by different slope instability processes, spatial scales and risk management phases. Results: Spaceborne optical Very High Resolution (VHR) and SAR data were applied at a basin scale for analysing shallow rapid-moving and slow-moving landslides in the emergency management and post-disaster phases, demonstrating their effectiveness for post-disaster damage assessment, landslide detection and rapid mapping, the definition of states of activity and updating of landslide inventory maps. The potential of UAV-DP for very high resolution periodical checks of instability phenomena was explored at a slope-scale in a selected test site; two shallow landslides were detected and characterized, in terms of areal extension, volume and temporal evolution. The combined use of GB-InSAR, TLS and IRT ground based methods, was applied for the surveying, monitoring and characterization of rock slides, unstable cliffs and translational slides. These applications were evaluated in the framework of successful rapid risk scenario evaluation, long term monitoring and emergency management activities. All of the results were validated by means of field surveying activities.

Review article: the use of remotely piloted aircraft systems (RPASs) for natural hazards monitoring and management

“…Landslide event mapping is a wellknown activity obtained through field surveys (Yoon et al, 2012;Santangelo et al, 2010), visual interpretation of aerial or satellite images (Brardinoni et al, 2003;Ardizzone et al, 2013) and combined analysis of lidar DTM and images (Van Den Eeckhaut et al, 2007;Haneberg et al, 2008;Giordan et al, 2013;Razak et al, 2013;Niculiţa, 2016). The use of RPASs for the identification and mapping of a landslide has been described by several authors (Niethammer et al, , 2010(Niethammer et al, , 2011Rau et al, 2011;Carvajal et al, 2011;Travelletti et al, 2012;Torrero et al, 2015;Casagli et al, 2017). Niethammer et al (2009) and Liu et al (2015) showed how RPASs could be considered a good solution for the acquisition of ultra-high-resolution images with low-cost systems.…”

Satellite radar data for back-analyzing a landslide event: the Ponzano (Central Italy) case study

“…This approach allows selecting not only the point-wise coherent scatterers (PS) but also the DS (distributed scatterers) points that typically correspond to homogeneous areas as bare soils or non-cultivated areas. The use of this type of analysis allows considerably increasing the number of measurement points (MP) in areas with low urban density, as in the proposed case study (Bellotti et al 2014;Notti et al 2014;Bianchini et al 2015a, b;Casagli et al 2017;Raspini et al 2017). Ferretti et al (2011) reported that the SqueeSAR algorithm is able to increase of one order of magnitude the number of MP, enhancing at the same time the signal-to-noise ratio of the single measurement and so improve the quality of the time series.…”

Landslide Mapping and Characterization through Infrared Thermography (IRT): Suggestions for a Methodological Approach from Some Case Studies

“…In this context, the availability of new remote sensing technologies, based primarily on satellite, aerial and terrestrial remote sensing platforms, can allow systematic and easily updatable acquisitions of data over wide areas, and therefore may improve the production of landslide maps, reduce costs and optimize field work [2,3]. In recent years, amongst the new methods for accurate landslide mapping, ground-based technologies such as digital photogrammetry (DP) [4][5][6], terrestrial laser scanning (TLS) [7][8][9], ground-based interferometric synthetic aperture radar (GB-InSAR) [10][11][12] and infrared thermography (IRT) [13][14][15], have been increasingly used as efficient remote surveying techniques for the prompt characterization and mapping of slopes affected by instability processes.…”