An Event-Based Inventory Approach in Landslide Hazard Assessment: The Case of the Skolis Mountain, Northwest Peloponnese, Greece

Aspasia Litoseliti,Ioannis K Koukouvelas,Vasiliki Zygouri,Konstantinos G Nikolakopoulos

doi:10.3390/ijgi9070457

Aspasia Litoseliti, Ioannis K Koukouvelas + Show 2 more

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https://doi.org/10.3390/ijgi9070457

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Abstract

Assessment of landslide hazard across mountains is imperative for public safety. Pre- and post-earthquake landslide mapping envisage that landslides show significant size changes during earthquake activity. One of the purposes of earthquake-induced landslide investigation is to determine the landslide state and geometry and draw conclusions on their mobility. This study was based on remote sensing data that covered 72 years, and focused on the west slopes of the Skolis Mountains, in the northwest Peloponnese. On 8 June 2008, during the strong Movri Mountain earthquake (Mw = 6.4), we mapped the extremely abundant landslide occurrence. Historical seismicity and remote sensing data indicate that the Skolis Mountain west slope is repeatedly affected by landslides. The impact of the earthquakes was based on the estimation of Arias intensity in the study area. We recognized that 89 landslides developed over the last 72 years. These landslides increased their width (W), called herein as inflation or their length (L), termed as enlargement. Length and width changes were used to describe their aspect ratio (L/W). Based on the aspect ratio, the 89 landslides were classified into three types: I, J, and Δ. Taluses, developed at the base of the slope and belonging to the J- and Δ-landslide types, are supplied by narrow or irregular channels. During the earthquakes, the landslide channels migrated upward and downward, outlining the mobility of the earthquake-induced landslides. Landslide mobility was defined by the reach angle. The reach angle is the arctangent of the landslide’s height to length ratio. Furthermore, we analyzed the present slope stability across the Skolis Mountain by using the landslide density (LD), landslide area percentage (LAP), and landslide frequency (LF). All these parameters were used to evaluate the spatial and temporal landslide distribution and evolution with the earthquake activity. These results can be considered as a powerful tool for earthquake-induced landslide disaster mitigation

Highlights

A common approach for studying slope failure by an earthquake or cumulative earthquakes is the inventory of the induced landslides
There are many criteria for long-term inventory maps depending on the purpose or the extent or the available remote sensing data that contribute to its temporal completeness [4,5]
The aspect ratio is defined as the landslide length to width (L/W)

Summary

Introduction

A common approach for studying slope failure by an earthquake or cumulative earthquakes is the inventory of the induced landslides. Landslide inventory, according to Cruden [1] and Fell et al [2] is the record of the location, classification, volume, activity, and date of occurrence, where known, of individual landslides in an area as inventory maps. There are many criteria for long-term inventory maps depending on the purpose or the extent or the available remote sensing data (i.e., aerial photographs or satellite images) that contribute to its temporal completeness [4,5]. In the case of earthquake-induced landslides, the completeness of the records of local seismicity are very important. According to Xu [6], landslide inventories based on remote sensing data can avoid missing a large number of small scale landslides and can obtain detailed and comprehensive earthquake-triggered landslide inventories

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