The long-term change of the shoreline location is a phenomenon, which is highly factored in the d... more The long-term change of the shoreline location is a phenomenon, which is highly factored in the design of construction projects along the coastal zone. Especially, beach erosion is characterized as one of the major problems at coastal areas and it is of high importance as a quite significant percentage of social development is concentrated in a relatively narrow zone not far from the waterfront. This study presents a methodology that aims to quantify the shoreline displacement rate by involving the processing of different types of remote sensing datasets such as aerial photographs, satellite images and unmanned aerial system data coupled with in-situ observations and measurements. Several photogrammetric techniques were used in order to orthorectify and ho-mogenize a time series of remotely sensed data acquired from 1945 to 2017, representing a rapidly relocating coastal zone at the southern part of Corinth Gulf (Greece), as a case study. All images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at the time period of each acquisition. The data were imported in a Geographic Information System platform, where they were subjected to comparison and geostatistical analysis. High erosion rates were calculated, reaching the order of 0.18 m/year on average whilst extreme rates of 0.70 m/year were also observed in specific locations leading to the segmentation of the coastal zone according to its vulnerability and consequently the risk for further development as well as the effectiveness of measures already taken by the authorities.
The thermal comfort conditions in a complex urban area is influenced by the surrounding structure... more The thermal comfort conditions in a complex urban area is influenced by the surrounding structures and obstacles which modify the incoming radiation fluxes. A measure of this modification is the sky view factor (SVF), which could be estimated in each point of a selected area if a high resolution digital elevation model (DEM), or other urban morphological data including the manmade infrastructure, are available. The goal of this study is to model the continuous SVF for a complex building environment in the campus of National and Kapodistrian University of Athens, based on a high resolution DEM (0.09 m). For this purpose, we applied the structure-from-motion (SfM) technique, which takes advantage of the interpretation of ultra-high resolution colour images acquired by remotely piloted airborne systems, also known as drones or unmanned aerial vehicles. A quantitative analysis, by applying statistical metrics, yields perfect agreement between modelled and observed SVF values, over the examined area. The proposed methodology could be applied for human-biometeorology research in micro scale complex urban environments.
The long-term change of the shoreline location is a phenomenon, which is highly factored in the d... more The long-term change of the shoreline location is a phenomenon, which is highly factored in the design of construction projects along the coastal zone. Especially, beach erosion is characterized as one of the major problems at coastal areas and it is of high importance as a quite significant percentage of social development is concentrated in a relatively narrow zone not far from the waterfront. This study presents a methodology that aims to quantify the shoreline displacement rate by involving the processing of different types of remote sensing datasets such as aerial photographs, satellite images and unmanned aerial system data coupled with in-situ observations and measurements. Several photogrammetric techniques were used in order to orthorectify and ho-mogenize a time series of remotely sensed data acquired from 1945 to 2017, representing a rapidly relocating coastal zone at the southern part of Corinth Gulf (Greece), as a case study. All images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at the time period of each acquisition. The data were imported in a Geographic Information System platform, where they were subjected to comparison and geostatistical analysis. High erosion rates were calculated, reaching the order of 0.18 m/year on average whilst extreme rates of 0.70 m/year were also observed in specific locations leading to the segmentation of the coastal zone according to its vulnerability and consequently the risk for further development as well as the effectiveness of measures already taken by the authorities.
The Aegean-west Anatolian orocline formed due to Neogene opposite rotations of its western and ea... more The Aegean-west Anatolian orocline formed due to Neogene opposite rotations of its western and eastern limbs during opening of the Aegean back-arc basin. Stretching lineations in exhumed metamorphic complexes in this basin mimic the regional vertical-axis rotation patterns and suggest that the oppositely rotating domains are sharply bounded along a Mid-Cycladic lineament, the tectonic nature of which is enigmatic. Some have proposed this lineament to be an extensional fault accommodating orogen-parallel extension, while others have considered it to be a transform fault. The island of Paros hosts the only exposure of the E-to NE-trending lineations characterizing the NW Cyclades and the N-trending lineations of the SE Cyclades. Here, we show new paleomagnetic results from isotropic, ca. 16 Ma granitoids that intruded both domains and demonstrate that the trend difference resulted from post-16 Ma ~90° clockwise and 10° counterclockwise rotation of the NW and SE blocks, respectively. We interpret the semiductile to brittle, low-angle, SE-dipping Elitas shear zone that accommodated this rotation difference to reflect the Mid-Cycladic lineament. We conclude a two-stage exhumation history for Paros that is consistent with regional Aegean reconstructions. Between ca. 23 and 16 Ma, the metamorphic rocks of Paros were exhumed from amphibolite-facies to greenschist-facies conditions along a top-to-the-N detachment. The Elitas shear zone then started to exhume the northwestern, clockwiserotating domain from below the southeastern, counterclockwise rotating domain since 16 Ma. From this, we infer that the Mid-Cycladic lineament is an extensional shear zone, consistent with geometric predictions that Aegean oroclinal bending was accommodated by orogennormal and orogen-parallel extension.
Information flow and management represents one of the main tasks of seismic risk mitigation. The ... more Information flow and management represents one of the main tasks of seismic risk mitigation. The recent experience, following a number of disastrous earthquakes in Greece during the last decade, underlined the necessity of a flexible system in order to support earthquake disaster response organizations. Due to the large volume of spatial data required, a GIS platform represented the most efficient choice for the development of such an application. A number of basic thematic layers, such as topography, administrative, ...
A series of methodologies are described in this paper aiming to quantify the natural hazard due t... more A series of methodologies are described in this paper aiming to quantify the natural hazard due to the coastal changes at a deltaic fan. The coastline of Istiaia (North Evia, Greece) has been chosen for this study as several areas of accretion and erosion have been identified during the past few decades. We combined different types of datasets, extracted from high resolution panchromatic aerial photographs and traced the contemporary shoreline by high accuracy surveying with Real Time Kinematics (RTK) GPS equipment. The interpretation of all shorelines required geo-statistical analysis in a Geographical Information System. A large number of high resolution morphological sections were constructed normally to the coast, revealing erosional and depositional parts of the beach. Retreating and extension rates were calculated for each section reaching the values of 0.98 m/yr and 1.36 m/yr, respectively. The results proved to be very accurate, allowing us to expand the developed methodology by using more complete time-series of remote sensing datasets along with more frequent RTK-GPS surveying.
In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic ... more In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic processes are strongly influenced by active faulting; in many cases such faults cannot be easily identified. In this paper we apply multidisciplinary analysis (morphotectonic indices, neotectonic mapping, geophysical surveys and remote sensing techniques) to map the recently-recognized east–west trending Pineios River normal fault zone with a high degree of accuracy, and to better understand its contribution to the evolution of the ancient region of Elis during Holocene time. Fault activity seems to be related to frequent changes in river flow patterns and to displacements of the nearby shoreline. We argue that fault activity is the main reason for migration of Pineios river mouth as documented for several time periods during historical time. Quantitative constraints on deformation caused by the faulting were applied through the application of the morphotectonic indices proposed in this paper, including drainage network asymmetry and sinuosity, and mountain front sinuosity, all of which indicate that this is a highly active structure. Slip rates calculated to be as high as 0.48 mm/yr for the last 209 ka (based on previously published dating) were verified by applied geophysical methods. The fault surface discontinuity was identified at depth using vertical electrical resistivity measurements and depositional layers of different resistivity were found to be clearly offset. Displacement increases toward the west, reaching an observed maximum of 110 m. The most spectacular landform alteration due to surface deformation is the north–south migration of the river estuary into completely different open sea areas during the late Quaternary, mainly during the Holocene. The sediment transport path has been altered several times due to these changes in river geometry with and the most recent seeming to have occurred almost 2000 years ago. The river estuary migrated to its contemporary position along the southern coast, settled on the hanging wall, inducing retrograding of the northern coast, and settled on the foot wall, with rates reaching the order of 0.52 m/yr, as concluded from historical and recently-acquired remote sensing data.
The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xy... more The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xylokastro (north coast of Peloponnese), in order to identify and evaluate the processes controlling its formation and evolution. Within this concept, a number of factors have been considered and evaluated; near-shore morphometry and granulometry along shore-normal profiles, the direction and potential volumes of long-and cross-shore sediment transport the decadal and future trends of coastline displacement, the available information for terrestrial sediment influx and the geological processes operating in the broader coastal region of Xylokastro (i.e. subaqueous slides) as well as human interference. On the basis of these results, the formation and evolution of this coastal stretch seems to be governed primarily by the neotectonic activity and relative change of sea level rise, and secondarily by the wave-induced near-shore sediment transport; the role of the latter could be enhanced substantially by human intervention (i.e. construction of marina, seafront walls). Moreover, the expected eustatic increase in sea level by the year 2100, could cause a coastline retreat up to 9 m (SLR=0.38 m) or >19 m (SLR≥1 m).
Aim Although all five of the major mediterranean-climate ecosystems (MCEs) of the world are recog... more Aim Although all five of the major mediterranean-climate ecosystems (MCEs) of the world are recognized as loci of high plant species diversity and ende-mism, they show considerable variation in regional-scale richness. Here, we assess the role of stable Pleistocene climate and Cenozoic topography in explaining variation in regional richness of the globe's MCEs. We hypothesize that older, more climatically stable MCEs would support more species, because they have had more time for species to accumulate than MCEs that were historically subject to greater topographic upheavals and fluctuating climates. Location Southwestern Africa (Cape), southwestern Australia, California, central Chile and the eastern (Greece) and western (Spain) Mediterranean Basin. Methods We estimated plant diversity for each MCE as the intercepts of species–area curves that are homogeneous in slope across all regions. We used two down-scaled global circulation models of the Last Glacial Maximum (LGM) to quantify climate stability by comparing the change in the location of MCEs between the LGM and present. We quantified the Cenozoic topographic stability of each MCE by comparing contemporary topographic profiles with those present in the late Oligocene and the early Pliocene. Results The most diverse MCEs – Cape and Australia – had the highest Ceno-zoic environmental stability, and the least diverse – Chile and California – had the lowest stability. Main conclusions Variation in plant diversity in MCEs is likely to be a consequence not of differences in diversification rates, but rather the persistence of numerous pre-Pliocene clades in the more stable MCEs. The extraordinary plant diversity of the Cape is a consequence of the combined effects of both mature and recent radiations, the latter associated with increased habitat heter-ogeneity produced by mild tectonic uplift in the Neogene.
Corinth Canal is an important technical construction with a significant role in marine and land t... more Corinth Canal is an important technical construction with a significant role in marine and land transportation for Greece. Whilst the main highway of the Corinth bridge is well monitored there is no similar monitoring scheme for landslide failures of the canal walls. This work presents an in-house developed real-time early warning landslide triggering system using wireless sensor network (WSN) nodes. Specifically, for the detection of different types of landslide processes (drift, slide and fall) a set of corresponding MEMS (Micro-Electro-Mechanical Systems) sensors (accelerometer, inclinometer, magnetometer) will be used. These sensors along with radio transmission unit and microprocessor comprise a WSN node. The option for in-situ processing (i.e transmitting only alerts) is possible in order to decrease the communication costs. In conjunction with the proposed WSN system, high accuracy geodetic techniques are used with terrestrial laser scanning (TLS) measurements. TLS is augmenting the point-based system to a spatial-based monitoring system. The paper describes the use of WSN node as triggering device in order to alert the users to begin TLS measurements. A description of the network topology is given along with the implementation of the system in selected control points on the canal walls. Real results are shown and the performance of the system is discussed.
Different observational techniques are compared in order to investigate possible correlations in ... more Different observational techniques are compared in order to investigate possible correlations in seismic activity. The study site is the island of Kefallinìa (Greece), where measurements available included (1) DInSAR, DGPS, and DEM data, (2) soil exhalation measured by monitoring Radon (Rn) well content, and (3) acoustic emissions (AE) at high and low frequency (point-like records with high temporal resolution). AE records provide: (1) relative time variation of the applied stress intensity and (2) the state of fatigue of stressed rock volumes, the AE source.
The water pathways of the underground river of Agia Triada (Karystos, Greece) and their generatio... more The water pathways of the underground river of Agia Triada (Karystos, Greece) and their generation are examined in this study. One of the longest caves explored in Greece is formed at heavily deformed metamorphic rocks and the suggested combined methodology, which includes traditional geological mapping, speleological exploration and remote sensing image interpretation, led us to the conclusion that the water flows along the hinge of a NE–SW- trending mega-fold . A number of faults that have been activated after the generation of the underground river, have altered its pathway by creating “knick-points” which host impressive subsurface waterfalls, the largest of which is about 20 m high. The extraction of morpho-lineaments from ortho-rectified satellite images revealed the importance of structures that were identified on the open surface mainly by high-resolution remote sensing data interpretation and are related to the cave development. This was made feasible with the use of the Ge...
A rg o li c o s G u lf N .E vo ic os Gu lf Peloponnessus Central Greece Gu lf of Co ri nt h S t u... more A rg o li c o s G u lf N .E vo ic os Gu lf Peloponnessus Central Greece Gu lf of Co ri nt h S t u d y A r e a
In this paper a coastal ecosystem is examined (Korissia lagoon, SW Corfu isl., Greece), of season... more In this paper a coastal ecosystem is examined (Korissia lagoon, SW Corfu isl., Greece), of seasonal saline content variability and its relationship with the lateral subsurface water exchange with the adjacent fresh and salty water-bodies. The broader area consists of a recently formed depositional basin where the alpine basement outcrops only at the northern part of the study area (Kavalovouni, Kontrakas hill). The major part is covered by post-alpine sediments slightly deformed. The upper layers of the series are covered by either alluvial deposits or old and recent dunes. The recent tectonic movements have deformed and sliced the area in a number of tilted fault blocks and the result is the brought up of the marly formation of M. Pleistocene age to the surface level. The significance of this formation is very high as it is impermeable and its original stratigraphic position was much deeper than the present sea level. A large number of geoelectrical soundings were carried out by us...
In this project the geological subsurface structure of the delta of the river Pinios is investiga... more In this project the geological subsurface structure of the delta of the river Pinios is investigated through the contribution of geophysical soundings. In order to investigate the lithologic structure of the entire deltaic field, geophysical soundings were performed with the geoelectrical method of vertical investigation of the resistivity distribution at 37 locations. The Schlumberger array was applied, which is a reliable preliminary geophysical technique for such environments, achieving an investigation depth of > 200-250 meters. Obtaining information on the geoelectrical characteristics of the formations expected under the alluvial silt of Pinios, we have to evaluate the results of the geophysical survey. Therefore 14 “in situ” measurements of electrical resistivity were carried out in surface outcrops of Neogene sediments, cyanoschists and serpentinites. An extensive geological overview of the wider visual field was conducted, geological measurements were recorded and plotte...
The long-term change of the shoreline location is a phenomenon, which is highly factored in the d... more The long-term change of the shoreline location is a phenomenon, which is highly factored in the design of construction projects along the coastal zone. Especially, beach erosion is characterized as one of the major problems at coastal areas and it is of high importance as a quite significant percentage of social development is concentrated in a relatively narrow zone not far from the waterfront. This study presents a methodology that aims to quantify the shoreline displacement rate by involving the processing of different types of remote sensing datasets such as aerial photographs, satellite images and unmanned aerial system data coupled with in-situ observations and measurements. Several photogrammetric techniques were used in order to orthorectify and ho-mogenize a time series of remotely sensed data acquired from 1945 to 2017, representing a rapidly relocating coastal zone at the southern part of Corinth Gulf (Greece), as a case study. All images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at the time period of each acquisition. The data were imported in a Geographic Information System platform, where they were subjected to comparison and geostatistical analysis. High erosion rates were calculated, reaching the order of 0.18 m/year on average whilst extreme rates of 0.70 m/year were also observed in specific locations leading to the segmentation of the coastal zone according to its vulnerability and consequently the risk for further development as well as the effectiveness of measures already taken by the authorities.
The thermal comfort conditions in a complex urban area is influenced by the surrounding structure... more The thermal comfort conditions in a complex urban area is influenced by the surrounding structures and obstacles which modify the incoming radiation fluxes. A measure of this modification is the sky view factor (SVF), which could be estimated in each point of a selected area if a high resolution digital elevation model (DEM), or other urban morphological data including the manmade infrastructure, are available. The goal of this study is to model the continuous SVF for a complex building environment in the campus of National and Kapodistrian University of Athens, based on a high resolution DEM (0.09 m). For this purpose, we applied the structure-from-motion (SfM) technique, which takes advantage of the interpretation of ultra-high resolution colour images acquired by remotely piloted airborne systems, also known as drones or unmanned aerial vehicles. A quantitative analysis, by applying statistical metrics, yields perfect agreement between modelled and observed SVF values, over the examined area. The proposed methodology could be applied for human-biometeorology research in micro scale complex urban environments.
The long-term change of the shoreline location is a phenomenon, which is highly factored in the d... more The long-term change of the shoreline location is a phenomenon, which is highly factored in the design of construction projects along the coastal zone. Especially, beach erosion is characterized as one of the major problems at coastal areas and it is of high importance as a quite significant percentage of social development is concentrated in a relatively narrow zone not far from the waterfront. This study presents a methodology that aims to quantify the shoreline displacement rate by involving the processing of different types of remote sensing datasets such as aerial photographs, satellite images and unmanned aerial system data coupled with in-situ observations and measurements. Several photogrammetric techniques were used in order to orthorectify and ho-mogenize a time series of remotely sensed data acquired from 1945 to 2017, representing a rapidly relocating coastal zone at the southern part of Corinth Gulf (Greece), as a case study. All images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at the time period of each acquisition. The data were imported in a Geographic Information System platform, where they were subjected to comparison and geostatistical analysis. High erosion rates were calculated, reaching the order of 0.18 m/year on average whilst extreme rates of 0.70 m/year were also observed in specific locations leading to the segmentation of the coastal zone according to its vulnerability and consequently the risk for further development as well as the effectiveness of measures already taken by the authorities.
The Aegean-west Anatolian orocline formed due to Neogene opposite rotations of its western and ea... more The Aegean-west Anatolian orocline formed due to Neogene opposite rotations of its western and eastern limbs during opening of the Aegean back-arc basin. Stretching lineations in exhumed metamorphic complexes in this basin mimic the regional vertical-axis rotation patterns and suggest that the oppositely rotating domains are sharply bounded along a Mid-Cycladic lineament, the tectonic nature of which is enigmatic. Some have proposed this lineament to be an extensional fault accommodating orogen-parallel extension, while others have considered it to be a transform fault. The island of Paros hosts the only exposure of the E-to NE-trending lineations characterizing the NW Cyclades and the N-trending lineations of the SE Cyclades. Here, we show new paleomagnetic results from isotropic, ca. 16 Ma granitoids that intruded both domains and demonstrate that the trend difference resulted from post-16 Ma ~90° clockwise and 10° counterclockwise rotation of the NW and SE blocks, respectively. We interpret the semiductile to brittle, low-angle, SE-dipping Elitas shear zone that accommodated this rotation difference to reflect the Mid-Cycladic lineament. We conclude a two-stage exhumation history for Paros that is consistent with regional Aegean reconstructions. Between ca. 23 and 16 Ma, the metamorphic rocks of Paros were exhumed from amphibolite-facies to greenschist-facies conditions along a top-to-the-N detachment. The Elitas shear zone then started to exhume the northwestern, clockwiserotating domain from below the southeastern, counterclockwise rotating domain since 16 Ma. From this, we infer that the Mid-Cycladic lineament is an extensional shear zone, consistent with geometric predictions that Aegean oroclinal bending was accommodated by orogennormal and orogen-parallel extension.
Information flow and management represents one of the main tasks of seismic risk mitigation. The ... more Information flow and management represents one of the main tasks of seismic risk mitigation. The recent experience, following a number of disastrous earthquakes in Greece during the last decade, underlined the necessity of a flexible system in order to support earthquake disaster response organizations. Due to the large volume of spatial data required, a GIS platform represented the most efficient choice for the development of such an application. A number of basic thematic layers, such as topography, administrative, ...
A series of methodologies are described in this paper aiming to quantify the natural hazard due t... more A series of methodologies are described in this paper aiming to quantify the natural hazard due to the coastal changes at a deltaic fan. The coastline of Istiaia (North Evia, Greece) has been chosen for this study as several areas of accretion and erosion have been identified during the past few decades. We combined different types of datasets, extracted from high resolution panchromatic aerial photographs and traced the contemporary shoreline by high accuracy surveying with Real Time Kinematics (RTK) GPS equipment. The interpretation of all shorelines required geo-statistical analysis in a Geographical Information System. A large number of high resolution morphological sections were constructed normally to the coast, revealing erosional and depositional parts of the beach. Retreating and extension rates were calculated for each section reaching the values of 0.98 m/yr and 1.36 m/yr, respectively. The results proved to be very accurate, allowing us to expand the developed methodology by using more complete time-series of remote sensing datasets along with more frequent RTK-GPS surveying.
In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic ... more In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic processes are strongly influenced by active faulting; in many cases such faults cannot be easily identified. In this paper we apply multidisciplinary analysis (morphotectonic indices, neotectonic mapping, geophysical surveys and remote sensing techniques) to map the recently-recognized east–west trending Pineios River normal fault zone with a high degree of accuracy, and to better understand its contribution to the evolution of the ancient region of Elis during Holocene time. Fault activity seems to be related to frequent changes in river flow patterns and to displacements of the nearby shoreline. We argue that fault activity is the main reason for migration of Pineios river mouth as documented for several time periods during historical time. Quantitative constraints on deformation caused by the faulting were applied through the application of the morphotectonic indices proposed in this paper, including drainage network asymmetry and sinuosity, and mountain front sinuosity, all of which indicate that this is a highly active structure. Slip rates calculated to be as high as 0.48 mm/yr for the last 209 ka (based on previously published dating) were verified by applied geophysical methods. The fault surface discontinuity was identified at depth using vertical electrical resistivity measurements and depositional layers of different resistivity were found to be clearly offset. Displacement increases toward the west, reaching an observed maximum of 110 m. The most spectacular landform alteration due to surface deformation is the north–south migration of the river estuary into completely different open sea areas during the late Quaternary, mainly during the Holocene. The sediment transport path has been altered several times due to these changes in river geometry with and the most recent seeming to have occurred almost 2000 years ago. The river estuary migrated to its contemporary position along the southern coast, settled on the hanging wall, inducing retrograding of the northern coast, and settled on the foot wall, with rates reaching the order of 0.52 m/yr, as concluded from historical and recently-acquired remote sensing data.
The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xy... more The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xylokastro (north coast of Peloponnese), in order to identify and evaluate the processes controlling its formation and evolution. Within this concept, a number of factors have been considered and evaluated; near-shore morphometry and granulometry along shore-normal profiles, the direction and potential volumes of long-and cross-shore sediment transport the decadal and future trends of coastline displacement, the available information for terrestrial sediment influx and the geological processes operating in the broader coastal region of Xylokastro (i.e. subaqueous slides) as well as human interference. On the basis of these results, the formation and evolution of this coastal stretch seems to be governed primarily by the neotectonic activity and relative change of sea level rise, and secondarily by the wave-induced near-shore sediment transport; the role of the latter could be enhanced substantially by human intervention (i.e. construction of marina, seafront walls). Moreover, the expected eustatic increase in sea level by the year 2100, could cause a coastline retreat up to 9 m (SLR=0.38 m) or >19 m (SLR≥1 m).
Aim Although all five of the major mediterranean-climate ecosystems (MCEs) of the world are recog... more Aim Although all five of the major mediterranean-climate ecosystems (MCEs) of the world are recognized as loci of high plant species diversity and ende-mism, they show considerable variation in regional-scale richness. Here, we assess the role of stable Pleistocene climate and Cenozoic topography in explaining variation in regional richness of the globe's MCEs. We hypothesize that older, more climatically stable MCEs would support more species, because they have had more time for species to accumulate than MCEs that were historically subject to greater topographic upheavals and fluctuating climates. Location Southwestern Africa (Cape), southwestern Australia, California, central Chile and the eastern (Greece) and western (Spain) Mediterranean Basin. Methods We estimated plant diversity for each MCE as the intercepts of species–area curves that are homogeneous in slope across all regions. We used two down-scaled global circulation models of the Last Glacial Maximum (LGM) to quantify climate stability by comparing the change in the location of MCEs between the LGM and present. We quantified the Cenozoic topographic stability of each MCE by comparing contemporary topographic profiles with those present in the late Oligocene and the early Pliocene. Results The most diverse MCEs – Cape and Australia – had the highest Ceno-zoic environmental stability, and the least diverse – Chile and California – had the lowest stability. Main conclusions Variation in plant diversity in MCEs is likely to be a consequence not of differences in diversification rates, but rather the persistence of numerous pre-Pliocene clades in the more stable MCEs. The extraordinary plant diversity of the Cape is a consequence of the combined effects of both mature and recent radiations, the latter associated with increased habitat heter-ogeneity produced by mild tectonic uplift in the Neogene.
Corinth Canal is an important technical construction with a significant role in marine and land t... more Corinth Canal is an important technical construction with a significant role in marine and land transportation for Greece. Whilst the main highway of the Corinth bridge is well monitored there is no similar monitoring scheme for landslide failures of the canal walls. This work presents an in-house developed real-time early warning landslide triggering system using wireless sensor network (WSN) nodes. Specifically, for the detection of different types of landslide processes (drift, slide and fall) a set of corresponding MEMS (Micro-Electro-Mechanical Systems) sensors (accelerometer, inclinometer, magnetometer) will be used. These sensors along with radio transmission unit and microprocessor comprise a WSN node. The option for in-situ processing (i.e transmitting only alerts) is possible in order to decrease the communication costs. In conjunction with the proposed WSN system, high accuracy geodetic techniques are used with terrestrial laser scanning (TLS) measurements. TLS is augmenting the point-based system to a spatial-based monitoring system. The paper describes the use of WSN node as triggering device in order to alert the users to begin TLS measurements. A description of the network topology is given along with the implementation of the system in selected control points on the canal walls. Real results are shown and the performance of the system is discussed.
Different observational techniques are compared in order to investigate possible correlations in ... more Different observational techniques are compared in order to investigate possible correlations in seismic activity. The study site is the island of Kefallinìa (Greece), where measurements available included (1) DInSAR, DGPS, and DEM data, (2) soil exhalation measured by monitoring Radon (Rn) well content, and (3) acoustic emissions (AE) at high and low frequency (point-like records with high temporal resolution). AE records provide: (1) relative time variation of the applied stress intensity and (2) the state of fatigue of stressed rock volumes, the AE source.
The water pathways of the underground river of Agia Triada (Karystos, Greece) and their generatio... more The water pathways of the underground river of Agia Triada (Karystos, Greece) and their generation are examined in this study. One of the longest caves explored in Greece is formed at heavily deformed metamorphic rocks and the suggested combined methodology, which includes traditional geological mapping, speleological exploration and remote sensing image interpretation, led us to the conclusion that the water flows along the hinge of a NE–SW- trending mega-fold . A number of faults that have been activated after the generation of the underground river, have altered its pathway by creating “knick-points” which host impressive subsurface waterfalls, the largest of which is about 20 m high. The extraction of morpho-lineaments from ortho-rectified satellite images revealed the importance of structures that were identified on the open surface mainly by high-resolution remote sensing data interpretation and are related to the cave development. This was made feasible with the use of the Ge...
A rg o li c o s G u lf N .E vo ic os Gu lf Peloponnessus Central Greece Gu lf of Co ri nt h S t u... more A rg o li c o s G u lf N .E vo ic os Gu lf Peloponnessus Central Greece Gu lf of Co ri nt h S t u d y A r e a
In this paper a coastal ecosystem is examined (Korissia lagoon, SW Corfu isl., Greece), of season... more In this paper a coastal ecosystem is examined (Korissia lagoon, SW Corfu isl., Greece), of seasonal saline content variability and its relationship with the lateral subsurface water exchange with the adjacent fresh and salty water-bodies. The broader area consists of a recently formed depositional basin where the alpine basement outcrops only at the northern part of the study area (Kavalovouni, Kontrakas hill). The major part is covered by post-alpine sediments slightly deformed. The upper layers of the series are covered by either alluvial deposits or old and recent dunes. The recent tectonic movements have deformed and sliced the area in a number of tilted fault blocks and the result is the brought up of the marly formation of M. Pleistocene age to the surface level. The significance of this formation is very high as it is impermeable and its original stratigraphic position was much deeper than the present sea level. A large number of geoelectrical soundings were carried out by us...
In this project the geological subsurface structure of the delta of the river Pinios is investiga... more In this project the geological subsurface structure of the delta of the river Pinios is investigated through the contribution of geophysical soundings. In order to investigate the lithologic structure of the entire deltaic field, geophysical soundings were performed with the geoelectrical method of vertical investigation of the resistivity distribution at 37 locations. The Schlumberger array was applied, which is a reliable preliminary geophysical technique for such environments, achieving an investigation depth of > 200-250 meters. Obtaining information on the geoelectrical characteristics of the formations expected under the alluvial silt of Pinios, we have to evaluate the results of the geophysical survey. Therefore 14 “in situ” measurements of electrical resistivity were carried out in surface outcrops of Neogene sediments, cyanoschists and serpentinites. An extensive geological overview of the wider visual field was conducted, geological measurements were recorded and plotte...
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Papers by Emmanuel Vassilakis