The growing human (urban and rural) demands for water in semi-arid regions, implies that the exploration of new locations of possible groundwater discharge and accumulation are critical for augmenting the limited water resources. The... more
The growing human (urban and rural) demands for water in semi-arid regions, implies that the exploration of new locations of possible groundwater discharge and accumulation are critical for augmenting the limited water resources. The region of Mani peninsula represents the southernmost part of continental Europe, forming a massive carbonate outcrop in the prolongation of the Taygetos Mountain, and hosts one of the largest and most spectacular karstic systems of Europe, the Cave of Diros. This karst system discharges in the sea and thermal infrared remote sensing proved its capability in monitoring temperature field. The purpose of this study is to evaluate the use of Landsat Thematic Mapper (TM) data for mapping and indicating temperature differences between the sea and the underground fresh water which discharges towards the sea, by creating a cold water plume. Several different points of groundwater discharge have been detected and mapped not only strictly along the coastal zone of the Mani peninsula, but as far as 1500 m from the coast as well. Moreover, following such modeling techniques their temperatures have been estimated. These points of discharge are aligned along two main orientations that are tectonically controlled. The major one is NNW-SSE trending and a secondary is E-W trending. Overall, the karstification process is highly controlled by the tectonic lineaments. The largest quantities of freshwater source from the massive carbonate mass of the Taygetos Mt and follow a NNW-SSE trending path.
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The focus of investigation in this paper is the reconstruction of different fault plane conditions and the primary interpretation of them, based on terrestrial close range LiDAR (Light Detection and Ranging) data. For reconstruction the... more
The focus of investigation in this paper is the reconstruction of different fault plane conditions and the primary interpretation of them, based on terrestrial close range LiDAR (Light Detection and Ranging) data. For reconstruction the slip per event along the bedrock scarp and where possible (e.g. postglacial scarp) an estimate regarding the slip rate of the individual faults we used the backscattered signal of the laser beam, the geomorphological geometry and the fault plane conditions. In this paper we discuss the N-S striking normal fault near Archanes in the Heraklion basin. To the north of this fault
zone the ancient Minoan temple Anemospillia (caves of the wind) is located, which was destroyed by an earthquake around 1700 BC and forms the nearest seismic source to the site.
zone the ancient Minoan temple Anemospillia (caves of the wind) is located, which was destroyed by an earthquake around 1700 BC and forms the nearest seismic source to the site.
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... 2 AON Benfield UCL Hazard Research Centre, Department of Earth Sciences, University College London, WC 1E 6BT, London UK. Received 13 July 2010; revised 13 January 2011; accepted 29 March 2011. Available online 23 April 2011.... more
... 2 AON Benfield UCL Hazard Research Centre, Department of Earth Sciences, University College London, WC 1E 6BT, London UK. Received 13 July 2010; revised 13 January 2011; accepted 29 March 2011. Available online 23 April 2011. Abstract. ...
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... Considering that the NAF entered the Aegean around 3.5±0.5 Ma (Dinter and Royden, 1993; Armijo et al., 1999; Yaltirak et al., 2000; Yaltirak and Alpar, 2002, Kreemer et al., 2004), a throw rate in the range of 1.01.4 mm/yr (1.2±0.2... more
... Considering that the NAF entered the Aegean around 3.5±0.5 Ma (Dinter and Royden, 1993; Armijo et al., 1999; Yaltirak et al., 2000; Yaltirak and Alpar, 2002, Kreemer et al., 2004), a throw rate in the range of 1.01.4 mm/yr (1.2±0.2 mm/yr) is extracted. ...
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Research Interests: Geology and Geomorphology
ABSTRACT Seismic hazard maps, in their vast majority, are constructed based only on the records of past earthquakes retrieved from instrumental or historical data. Although most scientists now agree that the observation period through the... more
ABSTRACT Seismic hazard maps, in their vast majority, are constructed based only on the records of past earthquakes retrieved from instrumental or historical data. Although most scientists now agree that the observation period through the historical catalogues is too short for the whole pattern of fault activity to be emerged, few attempts have been made to embody fault slip rate data into the hazard maps in order to fill in the observation gaps. In this study we show the way geological data can improve seismic hazard assessment by providing quantitative assessments of how geologically-recorded slip on active faults can be represented on seismic hazard maps. In Lazio-Abruzzo a large fault slip rate database has been collected from offset post-glacial features, supported also with published trench site data. Additionally to the measured values, another independent method of obtaining slip rate data was used from an equation, which is based on fault scaling arguments and can predict slip rates. The input data for the equation are the fault lengths and a well-defined slip rate measurement. Both measured and predicted values provide similar slip rates, implying that such an equation can potentially be applied in other extensional regions worldwide, particularly towards those settings where slip rates are difficult to extract. Hazard maps were constructed after using: i) relationships between coseismic slip values, rupture lengths and earthquake magnitudes, ii) relationships between earthquake magnitudes and intensity distributions, and iii) a simple model of two different shaking intensity levels one for the bedrock and another one for the flysch/Quaternary deposits. Our study provides a high spatial resolution map showing how many times each location has been shaken at intensity IX or higher during the last 18,000 years, which can be easily transformed to a map of recurrence intervals. These maps have also been developed in a GIS environment enabling us to run different scenarios and facilitate social economic approaches. Overall, these maps do not suffer from the incompleteness of the historical catalogues or temporal earthquake clustering problems because of the long time period considered, provide high spatial resolution and consider the influence of bedrock geology and local soil condition on the intensity distribution.
Mapping, dating and modeling of palaeoshorelines uplifted in the footwall of the 1981 Gulf of Corinth earthquake fault, Greece (Ms 6.9-6.7), are used to (1) assess its slip-rate history relative other normal faults in the area, (2) study... more
Mapping, dating and modeling of palaeoshorelines uplifted in the footwall of the 1981 Gulf of Corinth earthquake fault, Greece (Ms 6.9-6.7), are used to (1) assess its slip-rate history relative other normal faults in the area, (2) study strain localization, (3) reconcile geologic and ...
Page 1. Geophysical Research Abstracts Vol. 12, EGU2010-13310-2, 2010 EGU General Assembly 2010 © Author(s) 2010 Landslide hazard and forest fires - the relevance of geology for landslide type and development Tomas ...
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Wildfires are a major hazard in Greece suffering on average 1,509 wildfires and 36,151 burned hectares of forestlands every year. Since 1998 the Greek Fire Service is responsible for wildfires suppression and response, while prevention... more
Wildfires are a major hazard in Greece suffering on average 1,509 wildfires and 36,151 burned hectares of forestlands every year. Since 1998 the Greek Fire Service is responsible for wildfires suppression and response, while prevention and mitigation yearly directives are also being released by the General Secretariat of Civil Protection. The 3013/2002 Act introduced a major transfer of responsibilities from the national to local municipal and regional authorities, which are accompanied by supplementary financial support. Significant new features were established such as the operation of local coordination councils, the foundation of municipality civil protection offices, the establishment of the annually prevention planning for forest fires and the development of local action plans. The University of Athens has developed a Local Action Plan template for municipality administrative levels, integrating scientific techniques and technologies to public government management. The Local ...
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In the face of a growing number of natural disasters and the increasing costs associated with them, Europe and Greece in particular, have devoted significant efforts and resources in natural hazards mitigation during the last decades.... more
In the face of a growing number of natural disasters and the increasing costs associated with them, Europe and Greece in particular, have devoted significant efforts and resources in natural hazards mitigation during the last decades. Despite the significant legislative efforts (e.g. 1998/22/EC, 2001/792/EC, 2007/60/EC Directives, 3013/2002 Act) and even though a number of steps has been taken towards improving civil protection, recent catastrophic events have illustrated the weaknesses of current approaches. In particular, in Greece, events such as the 1999 Athens earthquake, the 2007 and 2009 wildfires have shown the inadequacy of prevention and mitigation practices. Given the enhanced civil protection responsibilities, given by the Greek national law (Acts 3013/2002, 3852/2010) to local authorities in Greece, this work analyses and evaluates the existing structure and current management framework under which local authorities function and examines their risk mitigation practices....
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The role of volunteers in disaster management is of decisive importance, particularly for major catastrophes. In Northern Europe, volunteers are the main group that responds even in regular low impact incidents. On the other hand, in... more
The role of volunteers in disaster management is of decisive importance, particularly for major catastrophes. In Northern Europe, volunteers are the main group that responds even in regular low impact incidents. On the other hand, in Southern Europe, state professionals hold the primary role. This is partly cultural, but it is also defined by the different types of hazards involved. For example, Southern Europe suffers from earthquakes and wildfires that can cause severe and widespread damage. This implies that there is a need for highly trained and skilled personnel, not only for efficiency purposes, but also in order to avoid casualties among the operating staff. However, the need of volunteers' involvement is well recognised both for prevention measures (mainly regarding forest fires) and for disaster management purposes particularly during major catastrophes whereas the professional personnel are outsourced. Moreover, the economic crisis stretches the public sector, decreasi...
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ABSTRACT Wildfires have significant geomorphological and hydrological impacts, such as the increasing of soil erosion and instability phenomena to fire-affected environment. In comparison to traditional methods, such as field inventories,... more
ABSTRACT Wildfires have significant geomorphological and hydrological impacts, such as the increasing of soil erosion and instability phenomena to fire-affected environment. In comparison to traditional methods, such as field inventories, remote sensing provides a cost-effective and rapid option in mapping the spatial and temporal variability of wildfires. The influence of the wildfires to soil erosion / sediment transport and their impact to the erosional and depositional environment and equilibrium and overall to the longer-term geological framework is often neglected in these studies. In this study, we examine whether the absence of vegetation due to the wildfires is indeed the main triggering mechanism for high erosional rates and try to quantify these parameters. In particular, the objective of the present study has been to assess the changes in soil erosion risk in Mediterranean setting as a result of a wildfire using remote sensing and Geographical Information Systems (GIS). As a case study is selected an area located close to the capital of Greece, in which a destructive wildland fire occurred in the summer of 2007, a year of the most catastrophic fires occurred in Greece in recent times. Landsat TM satellite imagery available before and shortly after the firebreak was utilised. Erosion risk maps before and after the fire event were estimated on the basis of the Revised Universal Soil Loss Equation (RUSLE) model. Ancillary data used in RUSLE implementation included the ASTER Global Digital Elevation Model, a geology map and field inventory conducted in the studied region. A soil erosion risk map with five classes (very low, low, medium, high) before and after the fire event was eventually developed from RUSLE within a GIS environment. In overall, areas having a minimal soil erosion risk before the fire showed a considerable increase in erosion risk after the fire, as a result of natural environment destruction occurred from the fire outbreak. Soil erosion risk changes were particularly evident in the steep sloping mountainous areas of the Mediterranean ecosystem of our study site. All in all, the methodology implemented herein proved capable in obtaining rapidly and cost-effectively a cartography of soil erosion risk and its changes in a Mediterranean environment. Keywords: erosion, erosion risk, RUSLE, wildland fires, Landsat TM, remote sensing, Geographical Information Systems, Greece.
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Athens and its surroundings have repeatedly been shaken by moderate damaging earthquakes, but strong local events and severe damage are not proven by instrumental, historical, and archaeological records for the last 2,300 years. Despite... more
Athens and its surroundings have repeatedly been shaken by moderate damaging earthquakes, but strong local events and severe damage are not proven by instrumental, historical, and archaeological records for the last 2,300 years. Despite this, the surroundings of Athens show clear signs of active faulting. In order to test the hypothesis of Holocene fault activity, we performed field mapping, georadar, morphological analyses and paleoseismological investigations at one of the prominent faults in N Attica, the Milesi Fault. Our data show evidence for recent seismic events and on-going tectonic activity. We can assign a minimum slip rate of 0.3 mm/yr and we are able to identify at least two post-glacial surface-rupturing earthquakes. These results make clear that strong local events in the vicinity of Greece’ capital must be considered in any seismic hazard assessment.
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Seismic intensity assignments for the 2008 Andravida (NW Peloponnese, Greece) strike-slip event (June 8, MW=6.4) based on the application of the environmental seismic intensity scale (ESI 2007) and the European Macroseismic scale (EMS-98). Geological structure, active tectonics, earthquake enviro...more