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TopIntroduction
Natural hazards such as earthquakes and landslides are phenomena or events that usually occur unexpectedly. The source of their creation is basically natural processes and their duration is mostly short. Their consequences are immediate in the man-made and non-human environment, as they can cause the loss of human life, the destruction of infrastructure, economic and social problems.
Many studies with different approaches have been made in an attempt to make a spatial assessment of the seismic and landslide risk (Arnous & Green, 2010; Kaur et al., 2018; Tan et al., 2015; Demertzis & Vatalis, 2021; Ilesanmi et al., 2021).
In the Region of Epirus (Fig. 1), Greece, many landslides are recorded every year, mainly in the Prefecture of Ioannina (one of the four prefectures). The occurrence of landslides is related to a combination of factors such as rainfall, geological formations (sands and clays) and high altitudes. Regarding the spatial risk of landslides, efforts have been made by creating a landslide susceptibility map that depicts all parts of Greece, including Epirus (Vassiliadis, 2010), while another susceptibility map has been constructed that refers exclusively to the Prefecture of Ioannina (Ziouti, 2019).
The seismic activity of the area could be characterized as moderate. However, large historic, seismic events have affected the area, so there is always the possibility of strong ground motion to reach levels that could inflict damage to the built environment. Regarding earthquakes and spatial risk, studies have been made, mainly on the occurrence of a seismic event that affects parts or areas of the P. Epirus, such as the Ioannina earthquake of 2016 (Pavlides et al., 2016) and the Kanallaki Preveza earthquake of 2020 (Lekkas et al., 2020; Valkaniotis et al., 2020).
Figure 1. Map of the Region of Epirus (Data Source: Institute of Geodynamics, 2017; Makropoulos et al., 2012)
In order to assess the spatial risk for these two geophysical phenomena for the entire P. Epirus, a geodatabase called “EPIRUS” was created, in order to host a really large volume of data, to make it more manageable and to simplify the process of drawing conclusions and conducting further scientific research.
Data entry, processing and the creation of the “EPIRUS” geodatabase were made by using Geographic Information Systems (GIS) and in particular ESRI ArcPro software. Data were georeferenced on EGSA 87 (the official Greek projection system). “EPIRUS” contains all the data collected, processed and generated after analysis, as it is presented in the following chapters.
Since the time prediction of earthquakes and landslides is not possible and while at the same time there is a lack of relevant studies for the entire study area, this study was an attempt to assess the seismic and landslide risk, in order to be able to spatially predict their catastrophic consequences, regardless of the time of their occurrence, for the whole Region of Epirus.
The infrastructures that are examined are the settlements, the road network and the cultural monuments.
TopMaterials And Methods
With the purpose to assess the spatial risks from earthquakes and landslides, the following procedure was followed: 1) collection, 2) import to a GIS and c) processing of all geospatial (comprising 51 vector files - feature classes and 31 raster layers). The data concern: public infrastructure, past earthquakes and landslides, faults, data on landslides, such as maps of spatial distribution of rainfall, slopes and geological formations, landslide susceptibility maps and zones of influence in relation to active faults. Below, we describe in more details the procedures regarding earthquakes and landslides.