The Use of Innovative Techniques for Management of High-Risk Coastal Areas, Mitigation of Earthquake-Triggered Landslide Risk and Responsible Coastal Development

Abstract

Coastal areas constitute a very dynamic environment, balancing between numerous natural and anthropogenic processes liable to sometimes hazardous geomorphic phenomena. Especially in tectonically active coastal regions and areas of high economic value, slope failures can have significant impacts and therefore need careful and detailed examination. This work uses Unmanned Aerial System (UAS)-aided photogrammetry and Terrestrial Laser Scanning (TLS) in tectonically active segments of the coastal zone of the Ionian Islands in Greece, to explore how their capabilities can help to improve our understanding of the structural integrity of the slopes. Results show that the two approaches are able to extract large numbers of discontinuity facets, in a more practical, rapid and safe way than conventional methods of rock slope stability analysis extending to unreachable yet important parts of the slope. Through this holistic record of the structural condition of the slope the two applications allow the identification of segments that are more prone to instability and failure. In this way, they improve our understanding of the prioritization of interventions aiming to enhance the prevention of slope failures, mitigating the associated risk and improving local development in these high-value locations.

A New Systematic Framework for Optimization of Multi-Temporal Terrestrial LiDAR Surveys over Complex Gully Morphology

“…TLS is an indirect measuring technique that actively emits laser beams from a terrestrial, tripod-based station while simultaneously measuring the distance to intersecting surfaces from received laser returns and forming a dense 3D point cloud [6][7][8]. Multi-temporal TLS surveys are often used for longitudinal detection and quantification of various spatio-temporal changes (STCs) caused by different geomorphic processes (e.g., landslides [9,10], rockfalls [11,12], glacial dynamics [13][14][15], coastal geomorphology [16][17][18], volcanism [19][20][21], etc.). As soil erosion represents both a rapid and complex geomorphic process and a serious environmental threat, multi-temporal TLS surveys are frequently used for detection and quantification of complex STCs induced by different sub-processes of soil erosion (e.g., rill erosion [22][23][24][25]; gully erosion [26][27][28][29][30][31], badland dynamics [1,32,33], etc.).…”

Monitoring and Quantifying Soil Erosion and Sedimentation Rates in Centimeter Accuracy Using UAV-Photogrammetry, GNSS, and t-LiDAR in a Post-Fire Setting

“…Due to the challenging station surroundings, which involved obstructions, limited satellite coverage, and unfavorable geometric conditions, occasional disruptions in the GNSS signals, specialized data processing techniques for GNSS, were crucial in the dynamic deformation/change detection monitoring process. Many researchers have selected this methodology for its advances [65,[136][137][138][139][140]. Zhang et al [124] provided a comprehensive analysis of the suitability of commonly used centimeter-level UAV images and sub-meter-level Google Earth images for interpreting multi-dimensional morphological parameters of different gully morphologies based on GNSS RTK field measurements.…”

“…This method, combined with recent advancements in computer technology, has positioned photogrammetry as a robust tool for geomorphological research [47]. Applications across various domains, such as monitoring riverbed topography [48][49][50][51], riverbank analysis [52,53], erosion [38,[54][55][56][57], landslides [58], erosion rate assessment [59][60][61][62][63][64], coastal analysis [65], and rockfall/rock slope stability analysis [66], have significantly expanded the realm of geomorphological analysis. In the past five years, there has been a notable interest in point cloud analysis based on the 3D surface reconstruction of infrastructure or natural surfaces [67][68][69][70][71][72].…”

Earthquake-Induced Tsunamis in Western Greece (Ionian Sea and Western and Southern Peloponnese): Use of Tsunami Quantities, Impact and ITIS-2012 Intensities for Highlighting Susceptible Areas

“…Typical recent examples comprise the August 1953 and the early 2014 earthquakes in Cephalonia, the 2003 and 2015 Lefkada earthquakes, the 2008 Andravida earthquake in the northwestern Peloponnese and the 2018 Zakynthos earthquake, among others. As a result, these earthquakes have had a multitude of effects: (i) on the local population, including human losses, injuries and internal migration; (ii) on the natural environment, including mainly rockfalls and slides on steep slopes and fault scarps and liquefaction in coastal areas; and (iii) on the built environment, including severe structural and non-structural damage to buildings and infrastructure [25][26][27][28][29][30][31].…”