Dimitrios Rozos

This study aimed to investigate the statistical correlation between the static and dynamic Young’s modulus of prasinites, a metabasic rock type that outcrops at various localities in the southern part of the Attica peninsula. A total of 39 cylindrical specimens was prepared and an extensive experimental program was carried out to determine the static and dynamic deformational properties for each specimen. Using ordinary least squares regression techniques, a new empirical linear equation was established between the aforementioned properties that can be used in the study region, or elsewhere where metabasic rocks with similar characteristics are investigated.

The geological, geomorphic conditions of a mountainous environment along with precipitation and human activities influence landslide occurrences. In many cases, their relation to landslide events is not well defined. The scope of the present study is to identify the influence of physical and anthropogenic factors in landslide activity. The study area is a mountainous part of the northern Peloponnesus in southern Greece. The existing landslides, lithology, slope angle, rainfall, two types of road network (highway-provincial roads and rural roads) along with land use of the study area are taken into consideration. Each physical and anthropogenic factor is further divided into sub-categories. Statistical analysis of landslide frequency and density, as well as frequency and density ratios, are applied and combined with a geographic information system (GIS) to evaluate the collected data and determine the relationship between physical and anthropogenic factors and landslide activity. The results prove that Plio-Pleistocene fine-grained sediments and flysch, relatively steep slopes (15°–30°) and a rise in the amount of rainfall increase landslide frequency and density. Additionally, Plio-Pleistocene fine-grained sediments and flysch, as well as schist chert formations, moderate (5°–15°) and relatively steep slopes (15°–30°), along with the amount of rainfall of >700 mm are strongly associated with landslide occurrences. The frequency and magnitude of landslides increase in close proximity to roads. Their maximum values are observed within the 50 m buffer zone. This corresponds to a 100 m wide zone along with any type of road corridors, increasing landslide occurrences. In addition, a buffer zone of 75 m or 150 m wide zone along highway and provincial roads, as well as a buffer zone of 100 m or 200 m wide zones along rural roads, are strongly correlated with landslide events. The extensive cultivated land of the study area is strongly related to landslide activity. By contrast, urban areas are poorly related to landslides, because most of them are located in the northern coastal part of the study area where landslides are limited. The results provide information on physical and anthropogenic factors characterizing landslide events in the study area. The applied methodology rapidly estimates areas prone to landslides and it may be utilized for landslide hazard assessment mapping as well as for new and existing land use planning projects.

The aim of this study is to investigate the statistical correlations between the point load strength index and certain physical properties, e.g. the dry density and the dry longitudinal ultrasonic wave velocity of prasinites (metabasites). Statistically significant correlations established between the physical properties as well as between each physical quantity and the point load strength index. According to bibliography, this is one of the first efforts to develop relations between physical and mechanical properties for this particular petrological type, and therefore the derived equations can be a useful tool to the investigation of these petrological types, either in the study area or in other sites, where prasinites of similar structural characteristics, are examined for the foundation of various constructions.

Land subsidence manifestation due to ground-water overexploitation in the Stavros – Farsala site (eastern part of Western Thessaly Basin) has been noticed since 1990. Because of this overexploitation, an excessive drawdown of the ground water level (20 to 40m) was noticed in the various successive aquifers the last decades. The subsidence phenomena resulted to the formation of tensile surface ruptures, which occurred since 2002, affecting roads and buildings. The geological environment of the study area consists of terrestrial Pleistocene deposits containing sands and gravels interbedded with clayey silt to silty clay horizons. These alternations of aquifers (permeable coarse-grained deposits) with aquitards (impermeable to low permeability strata) create a number of successive semi-confined to confined aquifer, initially artesian. This study examines the geological and the hydrogeological conditions of the wider study area, aiming to clarify their relationship with subsidence phenomena and to provide solutions for their suspension. Note that those phenomena are expected to be more incensed during the next few years.

SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis is a useful tool for sustainable development and decision making about environmental planning and water resources management. This analysis was applied in order to evaluate the water resources of the wider area of Sperchios River. Sperchios River basin, with an average altitude of approximately 810m, covers an area of 2116 km2. The river is recharged by many streams of permanent and periodic flow and discharges in Maliakos Gulf. The steep slopes, which are present within approximately 2/3 of the total length of the river course, form a rather mountainous topography (streamy, with crucial flooding peaks and very intense sediment yield). Only in the last downstream part of Sperchios course, the topography gradually changes into a lowland relief, with an extent at the river mouth of 1830 km2. At this part of Sperchios severe cases of flooding have been occasionally observed and reported. Regarding the SWOT applications on the wider area of Sperchios River, various data were processed (geological, meteorological, hydrological, hydrogeological, land use, socio-economic and environmental parameters) in order to suggest a water management planning in the area.

Land subsidence induced by the overexploitation of the aquifers in Kalochori village has been occurring since 1965. The excessive water pumping led to the development of surface subsidence reaching, in several areas, the maximum values of 3 to 4m. The evaluation of the geological, geotechnical and hydrogeological setting of the wider Kalochori region as well as the historical background of the subsidence phenomena provided variable data, which were finally used for the study of the phenomenon by means of a finite element method simulation. The availability of the various geodetic records allowed the cross-checking of the results and the conduction of all necessary back analyses. Also, the knowledge of the land use distribution and the activities taking place in the wider Kalochori region helped the rational interpretation of the phenomenon and the detection of its causal factors.

Landslides are one of the most frequent and disastrous natural hazards worldwide. Thus, the need of landslide susceptibility maps is of primary importance as they are both a useful tool for the land use planning and a necessary step for future development activities. This paper presents an integrated technique of analytical hierarchical process (AHP) and geographic information system (GIS) to create a landslide susceptibility map of the NE part of Achaia prefecture. The study area mainly consists of Neogene deposits and it is a part of the Corinthian graben, which characterized by intense neotectonic activity. Therefore, it is affected by many slope movements that usually cause serious damages in inhabitant areas and road networks. Based on field survey data analysis six parameters were chosen as major parameters that influence the stability of slopes to the direction of landslide manifestation. The AHP method identifies both the rate of the individual classes, and the weight of each factor. Spatial layers with their corresponding rates and weights were linearly combined to prepare the landslide susceptibility map, which includes four zones of slope movement’s susceptibility, namely a low, a moderate a high and a very high zone. The evaluation and final confirmation of the map was based on a great number of recorded landslides in the area.

In August 2007, a wildfire affected an area of approximately 135.000m2 in the Municipality of Zacharo, located in Southern Greece at the Peloponnesus peninsula, causing the loss of 41 human lives, and having a dramatic impact on both ecology and economic-social welfare. The present study applies a simplified model for the evaluation of soil erosion and the susceptibility to landslide manifestation on the hydrological basins of the Zacharo Municipality, as consequence of wildfire. The methodology was based on the evaluation and analysis of territorial parameters such as lithology, geomorphology, hydrography and land cover, which are thought to be directly or indirectly related to soil erosion. The final product was a series of hazardous maps showing pre and post-fire soil erosion. An almost double increase in the post-fire area of high vulnerability was identified, covering 48% of the total area, and affecting dramatically the nearby communities. The outcome of this study helped the local and prefectural authorities to address certain mitigating measures in order to face the disastrous consequences of post-fire soil erosion

The fine grained Plio-Pleistocene sediments encountered along the Patras Ring Road project (PRR) were distinguished into two lithological units, the Upper Geotechnical and the Lower Geotechnical Unit, based on the detailed engineering geological – geotechnical mapping, at a scale of 1:5000, on fieldwork, as well as on data gained from the boreholes drilled during the design and construction of the project. These units are distinguishable, stratigraphically successive and present basic differences in lithological composition, consistency and permeability and therefore different mechanical behaviour during construction.