Landslide Mapping and Susceptibility Assessment Using Geospatial Analysis and Earth Observation Data

Emmanouil Psomiadis,Despoina-Simoni Alexiou,Konstantinos Soulis,Andreas Papazachariou,Ioannis Charalampopoulos

doi:10.3390/land9050133

Emmanouil Psomiadis, Despoina-Simoni Alexiou + Show 3 more

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https://doi.org/10.3390/land9050133

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Journal: Land	Publication Date: Apr 28, 2020
Citations: 45	License type: CC BY 4.0

Affiliation: Agricultural University of Athens

Abstract

The western part of Crete Island has undergone serious landslide events in the past. The intense rainfalls that took place in the September 2018 to February 2019 period provoked extensive landslide events at the northern part of Chania prefecture, along the motorway A90. Geospatial analysis methods and earth observation data were utilized to investigate the impact of the various physical and anthropogenic factors on landslides and to evaluate landslide susceptibility. The landslide inventory map was created based on literature, aerial photo analysis, satellite images, and field surveys. A very high-resolution Digital Elevation Model (DEM) and land cover map was produced from a dense point cloud and Earth Observation data (Landsat 8), accordingly. Sentinel-2 data were used for the detection of the recent landslide events and offered suitable information for two of them. Eight triggering factors were selected and manipulated in a GIS-based environment. A semi-quantitative method of Analytical Hierarchy Process (AHP) and Weighted Linear Combination (WLC) was applied to evaluate the landslide susceptibility index (LSI) both for Chania prefecture and the motorway A90 in Chania. The validation of the two LSI maps provided accurate results and, in addition, several susceptible points with high landslide hazards along the motorway A90 were detected.

Highlights

Landslides are regarded among the most hazardous and recurrently appearing natural disasters globally [1,2,3,4,5]
From the analysis of the past landslide distribution, it was obtained that: (a) in the slope angle map, the 38% and 47.5% of previous Landslide Susceptibility (LS) are situated in very high and high slope angles, respectively; (b) in the geological map, 63.3% of past LS parts are located in Phyllites–Quartzites and
10.1% in olive groves and forest–shrub areas, respectively; (d) in the mean annual precipitation distribution map, 77.7% of past LS parts are situated in 600–800 m, and 800–100 mm classes; (e) in the aspect map 31% and 30% of past LS is located in N-NW-W, and NE-E directions; (f) in the distance to roads, streams and faults maps, 57.8%, 61% and 70% of the past landside events are placed in areas

Summary

Introduction

Landslides are regarded among the most hazardous and recurrently appearing natural disasters globally [1,2,3,4,5]. The triggering factors that cause landslide episodes are numerous and complexly interdependent, comprising intensive rainfalls, earthquakes, rapid stream erosion, geomorphological processes and human activities (deforestation of slopes, road construction, uncontrolled irrigation, quarries and mines, etc.) [6,7,8]. Foreseeing the place and time that a landslide will take place constitutes a complex issue, since the properties of geology and slope angle characteristics vary greatly over short distances, and the timing, location, and intensity of triggering events are difficult to be estimated [6]. Rainfall-triggered landslides are amongst the most frequent types, as well as the most devastating hazards, which cause extensive devastation to lives, properties and infrastructures worldwide [9,10,11,12,13]. The crucial precipitation that affects slope stability is determined by the meteorological conditions and geomorphological characteristics [14,15]

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