ABSTRACT. The Veria-Naousa ophiolitic complex represents a dismembered ophiolite unit, which is superimposed on a basement consisting of rocks belonging to the Pelagonian and Axios (Almopias subzone) isopic zones in northern Greece. Mantle peridotites are composed of variably serpentinised lherzolite and harzburgite intruded by a sparse network of pyroxenitic dykes. The serpentinised lherzolite and harzburgite contain Al-spinels (Cr#=38.83-42.52 and Mg#=58.94-64.77), Cr-spinels (Cr#=43.37-64.92 and Mg#=49.20-58.66) and magnesiochromites (Cr#=53.93-57.13 and Mg#=55.73-61.71). All of them display commonly richer-in-Cr cores rimmed by secondary ferrian chromite and magnetite. Whole-rock geochemical compositions and primary spinel chemical composition of these peridotites are analogous to peridotites that formed in a suprasubduction zone. Ιt is supported that the Mantle peridotites of the Veria-Naousa ophiolitic complex formed in a back-arc basin.

ABSTRACT. The ophiolite of Skyros mainly consists of serpentinized harzburgites, gabbroic rocks, dolerites, tholeiitic basaltic lavas, rodingites, as well as ophicalcites. This ophiolitic sequence, which practically comprises an ophiolitic mélange of pre-Middle Cretaceous age belonging to the Eohellenic nappe, has been affected by low to moderate metamorphic and metasomatic processes; however, some of their magmatic features have been preserved in gabbros and basalts. Their mineral chemistry as well as their whole rock chemistry suggests that these ophiolitic rocks are associated with supra-subduction related processes. The presence of vesuvianite crystals in rodingites, as well as the occurrence of relict spinels within serpentinitic rocks, further confirms this assumption. Geochemical and petrological comparison between Skyros ophiolitic rocks and similar rocks of the Eohellenic nappe in East Thessaly and other N. Sparades islands, reveal that they all share many petrogenetical features. Ophiolitic rocks of the upper tectonic unit of the Attico-Cycladic Zone may also join to this ophiolitic group of central Greece.

ABSTRACT. Ultramafic rocks from the Gerania Mountain ophiolite were tested as aggregates. Petrographic study through polarising microscope enabled us to determine the presence of dunite, harzburgite and lherzolite. A series of mechanical tests were carried out in order to determine the suitability of these rocks in a wide range of applications. Dunite and harzburgite samples show higher values of uniaxial compression strength than the lherzolites, as the presence of joints and the higher degree of alteration significantly affects negatively this mechanical property in the last rock-type. The same factors influence the point load index, too. Serpentinization and the presence of soft and laminate minerals also exert a negative influence on the resistance on abrasion and attrition, as well as the grinding of the rocks. The same factors influence negatively the point load index, too.

ABSTRACT. The aim of the present study is to apply a fast and reliable XRD method to identify the percentage of silica polymorphs and feldspars that industrial bentonite and perlite may contain, because these gangue minerals influence the quality of the final products. The current research was implemented by selecting of appropriate almost pure reference samples of bentonite and perlite in which specific amount of silica polymorphs and feldspars was added. The selection of all samples was based on the X-ray diffraction patterns. The synthetic mixtures produced were either with bentonite or perlite with a single added mineral or with two of them in percentages up to 10%. The minerals added to the reference samples were distinguishable in the XRD patterns in different percentages for each mineral added, but also in the two different reference samples. After evaluating of the XRD patterns of a series of samples, it was concluded that the lowest percentage of silica polymorphs and albite that was detected in the reference bentonite was 0.5% quartz, 1% cristobalite 10% opal-CT, and 1% albite, whereas the percentages for the reference perlite was 1% quartz, 2% opal-CT, 1% cristobalite and 0.5% albite. This method can be applied to any commercial bentonite and perlite bulk sample to define its purity concerning its silica polymorph and feldspar content.

ABSTRACT. Petrographic, geochemical and physicomechanical features were determined and inter-correlated in two representative ultrabasic samples from the Veria-Naousa ophiolite and two Pliocenic andesite samples, occurring at the east of the above complex. Results show that mineralogical and textural features are major factors affecting the physicomechanical properties in both lithotypes. The ultrabasic rocks display higher resistance to attrition and abrasion and lower water absorption values relative to the intermediate volcanic rocks, hence the first are predicted to show better in-service engineering performance. However, the degree of serpentinisation is detrimental, as a highly serpentinised ultrabasic sample yielded poor results, analogous to the andesites, in certain laboratory tests. Ophiolite complexes in Greece are abundant and they are distributed along several mainland areas. Hence setting evaluation criteria for their quality is important as they can potentially replace limestones, which are less resistant and durable, in several environmental and industrial applications.

ABSTRACT. Ophiolitic formation of Albanides, named as Mirdita zone, represents a compact segment of oceanic lithosphere of Middle-Upper Jurassic. Based on petrographic, geochemical and metalogenical features two belts are distinguished: western MORB and eastern SSZ types (Shallo, et.al 1995, Beccaluva et.al 1994). In fact, structural and geological units as well as many other elements have shed light on lack of a sharp separation between two belts (Manika 1994; Shallo et al., 1995; Gjata et al., 1996; Koller et al., 2009). Recent investigations have evidenced that different ultramafic massifs of western ophiolitic formation, represent an evident variation of their composition from harzburgite to lherzoliti -types. This composition reflects a different grade of partial melting of upper mante. Peridotites show a high variability, from 0.3 – 3.8 wt.% Al2O3, varying from small to highly extreme depleted peridotite. By Koller et.al, 2009, was suggested that the Albanian eastern belt, it seems to be formed by a more homogeneous hartzburgite mantle. Detailed petrologic and metallogenic investigations have evidenced that this belt changes also from one massif to another, naturally at a smaller level, therefore it is easier to be named relatively homogeneous. It is distinguished by a higher melting degree, chiefly of hartzburgitic-type, characterized by whole and thick ultramafic section, as well as by metalogenic variety, mostly of metallurgic-type of chromite mineralization. It is supposed that rock-forming and mineraluzation processes have been developed not uniformly along the ophiolitic belt.

ABSTRACT. This paper introduces MISTIC, a magnitude independent program for spatio-temporal earthquake clustering developed on the basis of a simple clustering algorithm which is implemented in Matlab. The method is conceptually based upon the comparison of the inter-event time and the epicentral/hypocentral distance between subsequent events, without any magnitude constrains. The code identifies spatial concentrations of seismic activity which additionally exhibit enhanced occurrence rates, significantly higher than the average, or background seismicity rates. The program interface provides visualization tools enabling the user to directly test and control the whole process being fast enough which is sufficiently fast even for relatively large catalogs. The description of the algorithm along with some examples are presented in this work. Moreover, an application in a local microseismicity catalog for Samos-Karaburun area, in eastern Aegean Sea, is also demonstrated. The identified clusters extracted from the analysis, exhibit special characteristics which vary from a typical main-shock/aftershock behavior to a swarm-like activity. Further testing and improvement of the source code are scheduled in order to constitute MISTIC a fast and useful tool for seismic cluster analysis.

ABSTRACT. A stochastic model for the study of Benioff strain release during aftershock sequences is suggested. The stochastic model is elaborated after a compound Poisson process and is applied on data of the M7.1 October 18,1989 Loma Prieta aftershock sequence in northern California, USA. The temporal evolution of the number of events is first modelled by the Restricted Epidemic Type Aftershock Sequence (RETAS) model and then the identified best fit model is incorporated in the energy release analysis. The suggested model is based on the assumptions that there is no relation between the magnitude and the occurrence time of an event first and second, that there is no relation between the magnitude of a certain event and magnitudes of previous events. The obtained results from the examination of the energy release reveal that the suggested model makes a good fit of the aftershock Benioff strain release and enables a more detailed study by identifying possible deviations between data and model. The real cumulative energy release values surpass the expected model ones, which proves that aftershocks, stronger than forecasted by the model, are clustered at the beginning of the Loma Prieta sequence.

ABSTRACT. We investigate temporal changes in seismic activity observed in the West Corinth Gulf and North-West Peloponnese during 2008 to 2010. Two major earthquake sequences took place in the area at that time (in 2008 and 2010). Our aim is to analyse Greek seismicity to attempt to confirm the existence or non-existence of seismic precursors prior to the strongest earthquakes. Perhaps because the area is geologically and tectonically complex, we found that it was not possible to fit the data well using a consistent Epidemic Type Aftershock Sequence (ETAS) model. Nor could we unambiguously identify foreshocks to individual mainshocks. Therefore we sought patterns in aggregated foreshock catalogues. We set a magnitude threshold (M3.5) above which all the earthquakes detected in the study area are considered as “mainshocks”, and we combined all data preceding these into a single foreshock catalogue. This reveals an increase in seismicity rate not robustly observable for individual cases. The observed effect is significantly greater than that consistent with stochastic models, including ETAS, thus indicating genuine foreshock activity with potential useful precursory power, if sufficient data is available, i.e. if the magnitude of completeness is sufficiently low.

ABSTRACT. The characteristic earthquake hypothesis is not strongly supported by observational data because of the relatively short duration of historical and even paleoseismological records. For instance, for the Corinth Gulf Fault System (CGFS), historical information on strong earthquakes exist for at least two thousand years, but they can be considered complete for M > 6.0 only for the latest 300 years, and therefore only few characteristic earthquakes are reported for individual fault segments. The use of a physics–based earthquake simulator has allowed the production of catalogues lasting 100,000 years and containing more than 500,000 events of magnitudes > 4.0. Our simulation algorithm is based on several physical elements, as an average slip rate due to tectonic loading for every single segment in the investigated fault system, the process of rupture growth and termination, and interaction between earthquake sources, including small magnitude events. The application of our simulation algorithm to the CGFS provided realistic fea-tures in time, space and magnitude behaviour of the seismicity. These features include long–term periodicity of strong earthquakes, short-term clustering of both strong and smaller events, and a realistic earthquake magnitude distribution departing from the Gutenberg-Richter distribution in the moderate and higher magnitude range.

ABSTRACT. We examine the nature of the seismogenetic system in South California, USA, by searching for evidence of non-extensivity in the earthquake record. We attempt to de-termine whether earthquakes are generated by a self-excited Poisson process, in which case they obey Boltzmann-Gibbs thermodynamics, or by a Critical process, in which long-range interactions in non-equilibrium states are expected (correlation) and the thermodynamics deviate from the Boltzmann-Gibbs formalism. Emphasis is given to background earthquakes since it is generally agreed that aftershock sequences com-prise correlated sets. Accordingly, the analysis is based on the accurate earthquake catalogue compiled of the South California Earthquake Data Center, in which after-shocks are either included or have been removed with a stochastic declustering pro-cedure. We examine multivariate cumulative frequency distributions of earthquake magnitudes, interevent time and interevent distance, in the context of Non-Extensive Statistical Physics, which is a generalization of extensive Boltzmann-Gibbs thermody-namics to non-equilibrating (non-extensive) systems. The results indicate a persistent sub-extensive seismogenetic system exhibiting long-range, moderate to high correla-tion. Criticality appears to be a plausible causative mechanism although conclusions cannot be drawn until alternative complexity mechanisms can be ruled out.

ABSTRACT. Interdependencies in earthquakes with M≥5.0 that occurred in the Greek territory during 1911-2014 are investigated by means of network analysis. The nodes of the seismic network represent seismic zones and the connections between them are given by the time succession of two earthquakes of any seismic zones. Five different approaches for determining the weighted connections are studied based on different normalizations of the frequencies of successions for each pair of nodes (areas). In particular, two approaches transform the transition matrix to transition probability matrix of a Markov chain or Gibbs sequence. The network structure is quantified by five selected network measures, and we assess how changes in seismicity (number of earthquakes or seismic moment release) in sliding time windows (e.g. decades) agree with changes in the network structure. It turns out that the best matching of seismicity and network measures is succeeded with the two approaches normalizing the maximum frequency of a succession pair, over the current time window or over all time windows, and with the approach that is based on probability distribution for the pairs of nodes. For the approaches transforming the transition matrix to transition probability matrix, a test is developed for the null hypothesis according to which the observed transition in a time window is equal to the predicted one on the basis on the information given from the previous time window. The developed parametric test is based on Chi-square null distribution and shows that the null hypothesis could not be rejected in some time windows, providing a tool for future seismic hazard assessment.

ABSTRACT. A relevant hazard in mountainous regions is the steep rock slopes concentrating rock falls. Although rock falls are characterized by smaller rock volumes compared to other landslide types, can also provoke severe damage to buildings, infrastruc-tures and human life due to their sudden and highly fast movement. The key to un-derstand the processes that result in rock fall onset is an integrated study of the major causing parameters that affect slope stability. A rock slope may be subjected to many forms of triggering factors including tectonic, geomorphic, seismic, climatic or even human induced damages. This contribution provides an overview of the previous and current research related to rock falls and uses case studies of North Peloponnese in order to prove the usefulness of these methods in the Greek territory. Collecting data and production of thematic maps by means of field and remote sensing investigations can yield far more updated results incorporated in hazard assessment techniques and protection measures.

ABSTRACT. The frequent lack of information to populations exposed to landslides is a component of the social vulnerability and can strongly increase the risk on lives and infrastructures. Determining the extent of the landslide hazard requires identifying those areas which could be affected by a damaging landslide. The users need to integrate different landslide data in order to first understand and then possibly become resilient to any potential catastrophic event. More precisely, public and private organizations can choose between different land use options to minimize the risk on the already existing infrastructures or to reduce the hazard itself through mitigation measures. From the other hand, the land use planners can also take best decisions before planning new infrastructures in high risk landslides’ areas. Based on these data we have also implemented new tools, available every day and reusable by anyone interested, to identify land areas susceptible for landslides. The tools are based on cloud web services, especially for the management and presentation of these datasets in order to provide stakeholders with valuable information about past distribution of the landslides, type of bed rock, rainfall etc. in order to focus on land use policies and assess an impending landslide.

ABSTRACT. Floods are suddenly and temporary natural disasters, which influence equally important the society and the natural environment, affecting areas that are not normally covered by water. In the context of flood mapping, different remote sensing techniques may contribute in a sufficient and effective way. This paper deals with mapping the spread of water bodies from natural levees of the river Evros and therefore the flood event on the surrounding areas of the river. In this work, radar data from Sentinel-1 mission as well as optical data from Landsat-8 were utilized. Specifically, Sentinel-1 data before flood events were treated with respectively during flood, yielding an image which reflects the propagation of the event. Moreover, Landsat-8 data were acquired with the aim of identifying and mapping of flooded areas, utilizing the Normalized Difference Water Index calculation. The results of the two methods were compared and flooded areas were evaluated.

ABSTRACT. SAR earth observation data can provide high quality flood maps and information to better assess the flood risk accordingly planning as well as to support civil protection authorities during emergency phase. The scope of this paper is to create flood extent maps from a series of SAR scenes of the Evros basin which represents a transboundary floodplain. The study uses time series SAR images of Sentnel-1 ESA’s Copernicus satellite system covering the period October 2014 to May 2015. The methodology tries to identify the flood that occurs in three main land cover classes, such as urban areas, bare or poorly vegetated soil and vegetated areas, tak-ing advantage of co- and cross-polarized SAR backscattering channels, and the In-SAR coherence to better characterize the landscape. Dual-pol SAR data provides the opportunity to have a better understanding and interpretation of flood detection due to way different land cover react to different polarizations. Thus, with the implementation of In-SAR coherence estimation we may achieve a better record and knowledge of the flooded areas, over time, in the specific region.

ABSTRACT. The long term change of the shoreline is a phenomenon, which is factored in the design of construction projects along the coastal zone. This study presents a methodology that aims to quantify the shoreline displacement rate. The described methodology involves the interpretation of different remote sensing data types, which make up a quite dense time series of representations for the coastline spanning from 1987 to 2012. The representation of the shoreline is based on geometrically corrected (ortho-rectified), historical, analogue, panchromatic, high resolution aerial photos of the area (1987, 1996) and latest generation, digital, multispectral, high resolution satellite images (2000, 2008, 2012). In all cases the images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline in each time period. All the data were imported in a Geographic Information System platform, where they were subjected to comparison and geo-statistical analysis. A large number of sections perpendicular to the coast (every 100 meters) was drawn and the relative motion of the coastline was calculated for each of them. The average rate of the calculated erosion is in the order of 24mm/year whilst extreme rates of 1m/year were also observed in specific positions.

ABSTRACT. Land subsidence is a common phenomenon occurring in several regions worldwide. The current work focus on the industrial-commersial area of Eleonas, Athens, where vertical displacements were identified by Persistent Scatterer Interferometry (PSI) analysis. The rate of deformation in the study area according to the PSI results, during the period from May 1992 to December 2000, ranged between -1.5 and -10 mm/yr. The evaluation of the geological, geotechnical and hydrogeological conditions of the area combined with the PSI data provided substantial information for the interpretation of the land subsidence phenomenon. Also, the knowledge of the land use distribution and the activities taking place in the area helped the detection of its causal factors.

ABSTRACT. The Alpine-Balkan-Carpathian-Dinaride (ABCD) metallogenic belt, which tectoni-cally evolved during Late Cretaceous to the present, is Europe’s premier metal-logenic province, especially for gold. Three spatially distinct tectonic and metal-logenic belts are associated with this belt. One of them is the Serbomacedonian-Rhodope Metallogenic Belt (SRMB) which intersects with a NNW-SSE trend the south eastern Balkan countries. This belt includes the geotectonic zones of Vardar (Axios), Circum-Rhodope, and the Serbomacedonian and Rhodope Massives. It comprises dominantly carbonate replacement or porphyry metal deposits, stratiform volcano-sedimentary deposits, skarns and various isolated magmatic-hydrothermal deposits. The most significant Au metallogeny centers of this belt are found in Bul-garia (i.e., Madjarovo, Ada Tepe, Madan, Lozen), Greece (i.e., Perama Hill, Sapes, Maronia, Olympias-Stratoni-Skouries, Gerakario-Vathi-Pontokerasia), F.Y.R.O.M. (i.e., Buchim, Ilovitza, Alshar), Kosovo (i.e., Trepca), and Serbia (i.e., Lece District: Kiseljak, Bakrenjaca). The metal reserves of all categories in the SRMB are 24 t Au, 14 t Ag and >100 mt (Pb+Zn) ore in Bulgaria, 743 t Au, 4100 t Ag, 5345 th.t Cu and 3125 th.t (Pb+Zn) in Greece, 106 t Au, 96 t Ag and 834 th.t Cu in F.Y.R.O.M., >150 mt (Pb+Zn) ore in Kosovo, 118 t Au and 1270 th.t Cu in Serbia. In addition many other sites inside this belt exist which are very promising for precious metals.

ABSTRACT. The Triades-Galana Pb-Zn-Ag-Au mineralization is a shallow-submarine epithermal mineralization located along NE-trending faults, NW Milos Island, Greece. It is hosted in 2.5–1.4 Ma pyroclastic rocks and is genetically related to andesit-ic/dacitic lava domes. Mineralization occurs as breccias, quartz-barite-galena veins and stockworks within sericite-adularia or kaolinitic altered rocks. The min-eralization is enriched in Mo, W and base- and precious metals (e.g. Pb, Zn, Ag) similarly to the neighbouring mineralization at Kondaros-Katsimouti and Vani, indicating common source of metals from a deep buried granitoid feeding western Milos with metals and volatiles. Paragenetic relations suggest early deposition of pyrite, followed by famatinite, polybasite and Ag-rich tetrahedrite, and then by enargite, suggesting fluctuating sulfidation states during ore formation. The evolu-tion from Sb- towards As–rich enrichment indicate a renewed magmatic pulse (probably in the form of magmatic gases) in the hydrothermal system. Silver is pre-sent in the structure of sulfosalts (up to 66.2 wt.% in polybasite-pearceite, 15.1 wt.% in tetrahedrite and 60 wt. % in pyrargyrite). Boiling processes (as evidenced by the presence of adularia accompanying intermediate-sulfidation ore) and mix-ing with seawater (presence of hypogene lead chlorides) and contemporaneous up-lift, contributed to ore formation.

ABSTRACT. The Lapis Lacedaemonius (krokeatis lithos) is a well-known meta-volcanic rock of great historical importance. Petrographic observations, mineral chemistry data, as well as geochemical analysis of selected samples, reveal that these rocks are porphyritic metabasaltic rocks which have been significantly affected by saussuritization and also a restricted silicification processes. They represent subduction related calc-alkaline volcanic rocks which also appear in the adjacent Hellenic Triassic volcanic outcrops, and that seem to be associated with the rift/drift phase within the Pindos oceanic realm. The unique features of the Lapis Lacedaemonius, when compared to geochemically similar volcanic rock outcrops, are mainly attributed to their distinct porphyritic textures, predominantly with microlithically textured groundmass along with the coarse grained plagioclase, and to saussuritization processes. The Lapis Lacedaemonius seems to have formed in a sub-volcanic system closely associated with epidosites, suggesting that metasomatism occurred within hydrothermal upflow zones.

ABSTRACT. Particulate matter originating from hydrothermal vents plays important role in controlling local seawater chemistry and sedimentation processes. Shallow submarine hydrothermal vents along Hellenic Volcanic Arc transfer significant quantities of particles enriched in basic metals. Fluids collected by scuba diving from two shallow hydrothermal venting areas on Kos Island in the Aegean Sea in East Mediterranean. Samples were filtrated and membrane filters leached with a mixture of acids. Chemical analysis performed in suspended particles for Fe, Mn, Cu, Pb, Cd, Ca, Ba, Sr, Li, Al and Si. The suspended particulate matter (SPM) flux varied from 0.93 to 8.64 mg/l and between 0.21 and 20.94 mg/l in two sites. Metal/Al ratios also vary significantly within a short distance. The pH of hydrothermal waters was from 5.50 to 5.95 in Kephalos Bay and from 6.09 to 6.53 in Bros Thermi suggesting gases CO2 and H2S may control pH values. Particles were dominated by Fe, Ca, Si and Al and strongly enriched in Mn, Cu, Pb and Ba. The chemistry of particles emitted strongly influencing the local sediment geochemistry and sea column chemistry. Three geochemical groups were identified being associated with distinct hydrothermal processes concerning sulphide minerals, carbonate substrate and deeper Al-Silicate rock basement.

ABSTRACT. Small occurrences of iron-oxide deposits at Sesi-Koropi in S. Hymittos, are hosted by an extensional brittle detachment zone between carbonate rocks of "Vari-Kirou Pira" and "Hymittos" units. Another low-angle fault separates a heterogeneous formation of schists, containing meta-ophiolitic blocks ("Lavrion" Unit), which is cut by high-angle normal faults that root in the detachment zone, reducing the total structural thickness of "Hymittos" marbles and bringing in contact the meta-ophiolitc lithologies with the "Vari-Kirou Pira" dolomites. Three mine caves were found along the detachment zone indicating that these iron deposits were possibly mined on a very small scale in the past. The mineralization is developed in a cataclastic zone a few meters thick (3-5m), forming thin rusty black encrustations and larger zones of alteration with a reddish to yellow brown hue. Scanning Electron Microscope (SEM) mineralogical study of the iron-ore deposit indicated that hematite is the primary iron-oxide mineral extensively replaced by goethite. Goethite appears with the typical colloidal form within voids showing typical open-space filling type microstructures. According to field evidence and the tectonic macro-structure of the area, the mineralization is associated with hydrothermal fluid circulation along the brittle detachment zone between meta-ophiolitic lithologies and carbonate rocks. Similar type iron-oxides mineralization in cataclastic zones were observed along other detachment zones in northern and southeastern Hymittos Mt. and further south towards Lavrion. This suggests that this type of mineralization is not local but has a broader development and regional implications for the tectonic evolution of the central and SE Attica.

ABSTRACT. The metallic mineralization in Kontaros-Katsimouti area is an epithermal Pb-Zn-Ag mineraliza-tion located along the NW-trending Kondaros-Katsimouti-Vani fault, NW Milos Island, Greece. It is hosted within propylitically and argillically altered dacitic flow dome and volcaniclastic sandstone and shows features typical of intermediate sulfidation deposits like colloform band-ing, cockade breccias and gangue adularia, Mn-rich carbonates and amethystine quartz. The Kondaros-Katsimouti system evolves at higher elevation into the Vani Ag-Pb mineralization, which occurs proximal to the Vani manganese deposit. The metallic mineralogical assemblage at Kondaros-Katsimouti includes mainly galena and sphalerite and minor pyrite. Silver is present in the form of Ag-(Cd)-rich tetrahedrite (up to 23.1 wt. % Ag) and polybasite included in galena. Bulk ore analyses indicate enrichment in W (up to 424 mg/kg) and Mo (up to 24 mg/kg), similarly to the other neighboring mineralizations in western Milos (e.g. Vani, Triades-Galana). This en-richment suggests a magmatic-hydrothermal contribution to the ore fluids, probably from a bur-ied granitoid at depth. Boiling, in addition to mixing processes between magmatic- and sea-water, resulted in pH increase, oxidation and temperature decrease, and resulted into ore deposition.

ABSTRACT. This presentation outlines methodological aspects of earthquake forecasting. The recurring debates concerning predictability of earthquakes clearly show how this problem is centred on the difficulty of systematically testing the numerous methodologies that in the years have been proposed and sustained by the support-ers of prediction. This difficulty starts, sometimes, from the lack of a quantitative and rigorous definition of the concerned precursor, and other times from the lack of continuous observations, upon which statistical analyses could be based. After an introduction concerning the definition of earthquake precursors, the way how to validate forecast hypotheses and the cost associated to their opera-tional application, I give two examples of time-dependent hazard models, for long-term and short-term earthquake forecasts respectively. Considering the long-term forecast modelling, the effect of stress change due to previous historical earthquakes on the probability of occurrence of future earth-quakes on neighbouring faults is taken into account. Following a standard meth-odology developed a couple of decades ago, the probability of occurrence in the next 50 years for a characteristic earthquake on known seismogenic structures can be estimated by a time-dependent renewal model. Then, a physical model for the Coulomb stress change caused by previous earthquakes on these structures is ap-plied. The influence of this stress change on the occurrence rate of characteristic earthquakes is computed taking into account the permanent perturbation (clock advance). The method so developed is applied to the computation of earthquake hazard of the main seismogenic structures recognized in the Southern Apennines region, for which both historical and paleoseismological data are available. A popular short-term time-dependent hazard forecast model is the epidemic model. In this model earthquakes are regarded as the realization of a stochastic point process, and their magnitude distribution is described by the Gutenberg-Richter law with a constant b-value. The occurrence rate density is computed by the sum of two terms, one representing the independent, or spontaneous activity, and the other representing the activity induced by previous earthquakes. While the first term depends only on space, the second one is factored into three terms that respectively include the magnitude, time and location of the past earthquakes. An example of application of the epidemic model to the 2009 L’Aquila seismic series is shown.

ABSTRACT. In this study it is proposed that spatially detecting low b values in certain segment faults in conjunction to the spatial earthquake density of the corresponding areas, can be used in order to locate faults asperities. This hypothesis is tested in the area of Corinth Gulf where we have processed data from the earthquake catalog of the Aristotle University of Thessaloniki, during a significant period of 45 years, from 1970 until 2015. From the calculations of b values and earthquake density in certain regions asperity patterns have been observed: asperity located by small b values and low densities coincide with proposition of possible asperity found in literature. Based on these facts we reproduce the hypothesis of an Asperity in the south area of Corinth Gulf between the Helike and Xilokastro faults.

ABSTRACT. Earthquakes with magnitude M>=5.2 that occurred in the area of central Ionian Islands (1911-2014) are assumed to form a semi-Markov chain, aiming to contribute in the field of seismic hazard assessment. The sojourn times are considered to be geometric or approximated by Pareto distributions. Destination probabilities are examined and the results demonstrate that in many cases these probabilities become higher adequately forecasting the magnitude class of an anticipated earthquake. The geometrically distributed model can also reveal the more probable occurrence time of the next earthquake since for this model the destination probabilities were found to obtain many times their maximum values for the real occurrence time. The successful forecasting as for the occurrence time is 63.75% for all earthquakes and becomes 71.42% for the larger magnitude events (M>=6).

ABSTRACT. Εarthquake generation causes spatio-temporal stress changes on adjacent fault segments that can alter the occurrence probability of subsequent earthquakes onto them. The interaction is investigated with the Linked Stress Release Model, applied to fit historical data from two areas that accommodate high seismicity, the Corinth Gulf and the Central Ionian Islands. These two areas are divided in two subareas, based on seismotectonic features; Corinth Gulf is divided in the western and eastern part, whereas the area of Central Ionian Islands is divided in Kefalonia and Lefkada subareas. The results establish interactions between the subareas, especially in the Central Ionian Islands, and underline the differences in tectonic structures and earthquake mechanisms between these areas. Particularly, the seismicity in the Central Ionian Islands is proved to be more complex and active and yet more difficult to be examined, whereas the LSRM fits the Corinth Gulf data more easily.

ABSTRACT. Seismic excitations occur as mainshock-aftershock sequences (MS-AS) encompass-ing a strong event called mainshock with the largest magnitude in the set, or as earthquake swarms (ES) when a distinctive main event is absent. In regions as the gulf of Corinth, where active deformation is manifested with frequent seismicity bursts, it is important to distinguish MS-AS from ES for providing information on the physical process of earthquake generation and contribute to the seismic hazard assessment. For this purpose, a highly accurate local earthquake catalogue was compiled and an effort was made for clusters identification after establishing certain criteria based on spatio-temporal seismicity properties. The skewness and kurtosis of moment release history were calculated considering the normalized time of every event in a cluster since the starting time of the cluster and its seismic moment. For MS-AS we found large positive values for skewness and kurtosis contrary to ES that exhibit negative to low positive values for skewness and lower values for kurtosis. In order to verify the classification of clusters, the b-value, the spatial size and the number of events of each cluster were examined. Finally, a scaling relation between rupture zone and magnitude was found for the MS-AS sequences.

ABSTRACT. In this study we use Landsat 8 OLI satellite imagery in order to identify and map alteration zones in Limnos island (N. Aegean, Greece). Pre-processing included sea and vegetation masking. In order to enhance spatial resolution, data fusion to 15m is performed. A lineament map is extracted from the panchromatic image that gives the general tectonic view of the island. The detection and mapping of alteration minerals is performed using specific band ratios and consequent composite images. The colour composite using bands 10, 11, 7 (RGB) show the spectral signature and general distribution of silica. Band ratios 6/7, 4/2, 6/5, reveal alteration zones containing iron oxides, clay alteration and ferrous minerals correspondingly. The aforementioned analysis has shown that hydrothermally alteration areas in Limnos are located in the west part of the island and at the Fakos Peninsula, Sardes, Roussopouli and Paradeisi hill. These areas are compared and validated with the reported field work. We conclude that hydrothermal alteration zones can indeed be detected and mapped using medium resolution satellite multispectral data. However, for the identification and mapping of specific types of rocks and minerals, a sensor with high spectral resolution is required.

ABSTRACT. Remote Sensing and photogrammetric techniques have always been used in geological applications. Current advancements in the technology behind Unmanned Aerial Vehicles (UAVs), in accordance with the consecutive increase in affordability of such devices and the availability of photogrammetric software, makes their use for large or small scale land mapping more and more popular. With the UAVs being used for mapping, the problems of increased costs, time consumption and the possible accessibility problems -due to steep terrain-, are all solved at once. In this study, a custom-made UAV with 2 cameras onboard, is used to monitor two complex –regarding their topography- regions in Western Greece. One open pit limestone mine and a landslide occurring on sandy-clayous sediments. Both regions were mapped using surveying instruments like tachymeters and geodetic GPS, as well as using the aforementioned UAV system. 3D models of both regions were created using off-the-shelf photogrammetric software. For the creation of the 3D models, multiple targets were placed on the ground, to indicate GCPs with precisely known coordinates that could be identified in the high-resolution air photos, in order to maintain low Root Mean Square Error, while creating the DSMs and Orthophotos. In addition, the fish-eye effect caused by the cameras’ wide-angle lens was taken into consideration, regarding whether or not it affects the models’ overall geometric accuracy. Finally, the 3D models were compared to the survey measurements and the results are presented in this paper.

ABSTRACT. Since 2013, NASA and ESA, in cooperation with Charles University in Prague (Czech Republic), have been joining forces and sharing expertise within the organization of annual Trans-Atlantic-Training (TAT) events in Eastern European countries. TAT concerns capacity building on Earth Observation from Space and focuses mainly on land cover/land use applications. With three TATs already organized between 2013 and 2015, the purpose of this paper is to provide an overview of the context and achievements so far, to increase the visibility of these events to larger audiences in Eastern Europe and to discuss the future prospects. To this end, some background information is initially provided, with subsequent description of each TAT event, concerning its organization, thematic content and participants. The paper concludes with an overall assessment and a vision for the future of TAT, including its enlargement with the engagement of participants from more countries.

ABSTRACT. Vocational Education and Training (VET) and Life-Long Learning (LLL), stand at the forefront of Europe’s strategic policies in Education, in response to the lack of students’ interest in STEM and the emerging needs for new skills in the labour market. Space can be a particularly useful platform for attracting students to STEM, environmental as well as topics related to geospatial information, as many state-of-the-art technologies used in everyday life are space-based, while space seems to also be creating a genuine interest among most learners. This study focuses on the plethora of European Space Agency (ESA) Earth Observation (EO) education material readily accessible, at no cost and available in several languages. Undertaking the effort to optimize/extend the use of these existing EO educational resources also in VET and LLL, for promoting STEM subjects, as well as for the development of green and geospatial skills, would be to the mutual benefit of both ESA and the European Union. Finally, it is proposed that an assessment of the utility and potential for the overall ESA Education resources (other than EO), but also of other Space Agencies and relevant institutions active in space education, in VET and LLL would be of particular interest.

ABSTRACT. The purpose of this paper is to present the framework, content, outcomes and the lessons learnt from the 2015 Committee on Earth Observation Satellites (CEOS) course on geological disasters management, delivered within the 2015 CEOS Dis-tance Education Course entitled “Remote Sensing Technology for Disaster Man-agement” - a joint effort by CEOS Agencies, in particular of the Working Group on Capacity Building & Data Democracy (WGCapD) and the Working Group on Dis-asters (WGDisasters).

ABSTRACT. Attapulgite from the Ventzia Basin, Western Macedonia, Greece, was used as a template for preparing amorphous carbon nanotubes by vapor deposition polymer-ization (VDP) method and two different alcohols, furfuryl alcohol and ethylene glycol, as carbon source. The morphology and structure of the as-prepared carbon nanotubes were investigated by means of scanning electron microscopy and a transmission electron microscopy. X-ray diffraction and Raman spectroscopy were additionally employed. The amorphous nature of the carbon nanotubes has been confirmed by the XRD and the SAED pattern, as well as the Raman spectrum. No noticeable difference was observed in the morphology and structure of the as-prepared carbon nanotubes regarding the type of alcohol used as carbon source. However, a difference in the quantity of the produced carbon nanotubes was no-ticed, with the furfuryl alcohol, as carbon source, producing a larger amount of carbon nanotubes than the ethylene glycol

ABSTRACT. Thirty two (32) locations of zeolitic rocks from Thrace (29 from Evros prefecture and 3 from Rhodope prefecture) were investigated for their mineralogical composi-tion by X-Ray Diffraction (XRD) method. According to EU Regulation No 651/2013, clinoptilolite of sedimentary origin (zeolitic tuffs) with ≥80 wt% clinoptilolite, ≤20 wt% clay minerals, free of fibres and quartz, can be used as feed additive for all animal species. The zeolitic rocks of Thrace on average contain, 23-89 wt% HEU-type zeolite (clinoptilolite-heulandite), 8-45 wt% mordenite (ten locations), 24 wt% analcime (one location), 1-11 wt% mica, 1-11 wt% clay minerals, 3-37 wt% quartz, 2-29 wt% cristobalite, 3-34 wt% feldspars and 0-22 wt% amorphous materials. Only one location contains 89 wt% HEU-type zeolite (clinoptilolite-heulandite), 2 wt% clay minerals, is free of fibres, but unfortunately it contains 3 wt% quartz and 2 wt% cristobalite. Considering the mineralogical composition, the zeolitic rocks of Thrace do not meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additives for all animal species and consequently as nutrition supplements, since the zeolitic rocks in all locations, contain on average 3-37 wt% quartz, 2-29 wt% cristobalite, 8-45 wt% mordenite (fibrous zeolite) in 10 locations, 24-65 wt% zeolites (HEU-type ± mordenite ± analcime) in 28 locations, 74 wt% HEU-type zeolite in 2 locations and 77 wt% HEU-type zeolite in 1 location.

ABSTRACT. The Hellenic Natural Zeolite (HENAZE) is free of fibres and contains 89 wt% clinoptilolite, 3 wt% mica + clay minerals, 3 wt% quartz, 2 wt% cristobalie ± tridymite and 3 wt% feldspars. HENAZE do not meet the requirements of the EU Regulation No 651/2013, and thus cannot be used as feed additive for all animal species and consequently as nutrition supplement, since it contains 3 wt% quartz. HENAZE is suitable for use as soil conditioner, since the concentration of trace elements are lower than the maximum allowable concentrations in agricultural soils (EU Directive 278/1986). HENAZE as soil conditioner: a) improved the pH of acid soils by 47-55%, b) reduced the leaching of metals by 33-71% from contaminated soils, c) reduced the Hg concentration by 47-78% in shoots and roots of plants, d) increased the production of agricultural products by 17-95%, e) decreased the plant-losses in new vineyard by 12% and f) improved the quality of tomato by 4-46%. The HENAZE neutralized sewage-sludge (producing zeo-sewage-sludge), industrial-sludge (producing zeo-sludge), battery solid waste and mine solid wastes (mine-tailings). The zeo-sewage-sludge and zeo-sludge are odorless, cohesive and suitable for safe deposition. The treatment of sewage-sludge and industrial-sludge with the HENAZE, reduced the leaching of metals by 91-100% and of NO3- by 81-82%. Depending on the trace element contents, the zeo-sewage-sludge can be used as soil conditioner. HENAZE sorbed-removed 37-92% of metals, radionuclides and cyanobacteria from their solutions and waters. The treatment of wastewaters (urban, dyeing-industry, industrial area and tanning-work) with HENAZE, improved the quality characteristics by 48-99%. The HENAZE reduced the NO3- load by 54-94% in groundwater, nitrate-solutions, industrial and urban wastewaters. Considering, the European, Global and Greek legislation, the mineralogical, chemical, morphological and radiological characteristics, as well as the leachability and bioavailability of chemical elements, the specifications for the different applications-uses of the zeolitic tuffs are defined.

ABSTRACT. Late Miocene to Pliocene volcanism is represented by development of lava domes, nuée ardentes and pyroclastic fall and flow (ignimbrites) deposits in the WSW and NW of Konya city. The lava dome contains various mafic microgranular enclaves (MMEs), which have various size (a few cm to a few meters), shape (ellipse/sphere to rounded), with a well-developed chilly zone. The MMEs samples are situated on mostly basaltic andesite and andesite, and a few MME samples on basaltic trachy-andesite area while the host rocks are concentrated on dacite and andesite areas. The felsic samples have more fractionated chondrite-normalised REE pattern (La/YbN : 9.5-18.1) than MMEs (6.7-16.0) ones, but both have slightly developed negative Eu anomaly ( Eu/Eu*: 0.67-0.89 in felsic rocks, 0.68-0.87 in MMEs). In primitive mantle-normalized spider diagram, the MMEs and felsic rocks have nega-tive Nb, Ta, P and Ti anomalies, indicating some subduction component in their genesis. Based on geochemical data, the MMEs are suggested to have been formed by hybridization of basic magma mingled with partially crystallized felsic magma Erenlerdagı, volcanism, Mafic enclaves

ABSTRACT. Late Miocene to Pliocene volcanism produced lava domes with mafic microgranular enclaves (MMEs), nuée ardentes and pyroclastic fall and flow (ignimbrites) deposits in the WSW and NW of Konya city. All samples are predominantly high K-calc alkaline in composition but calc-alkaline and shoshonitic composition also exist. The felsic volcanics are mainly dacite, andesite, basaltic trachyandesite and rare trachyandesite in compositon. But, the MMEs have basaltic andesite and andesite compositon. SiO2 increases with decreasing TiO2, FeOt, MgO and CaO, suggesting fractional crystallization of mafic minerals. All samples have fractionated chondrite-normalised REE pattern (La/YbN: 6.7-18.1), and negative Eu anomaly (Eu/Eu*: 0.67-0.89), indicating plagioclase fractionation. In primitive mantle-normalized spider diagram, the samples show an enrichment in large ion litophile elements (LILE) such as Cs and Ba, and depletion in high field strength elements (HFSE), e.g. Dy and Y. They show negative Nb, Ta and Ti anomalies, indicating a subduction signature for their genesis. Based on geochemical data, the volcanics are suggested to have been formed by Assimilation-Fractional Crystallization (AFC) and/or magma mixing process. Various geotectonic diagrams imply volcanic arc to post collisional setting for the samples.

ABSTRACT. The most common test of breaking rocks in the laboratory under com-pression has provided the basis for most of the widely used modeling of faulting and the earthquake instability in the earth’s crust. But it has not been able to explain the actual complexity of fault systems insitu. Howev-er a greatly generalized lab experiment - widely overlooked for decades - provides the missing links needed to begin to understand the actual com-plexity of fault systems insitu.

ABSTRACT. Broad band seismic waveforms are used to determine the source model of the 16 April 2015 (UTC 18:07:44) earthquake, Mw6.1, which occurred 14 km SW of Kasos Island, in the eastern Hellenic subduction zone. The focal mechanism of the mainshock indicates the activation of a N-S (N11°E) striking reverse fault, while most of the aftershocks are connected with strike-slip faulting, with the T-axes showing along arc extension. We performed a finite fault slip inversion, allowing for the rake angle to vary across the fault, to capture the variation in the slip vectors. The rupture initiated in the lower crust, at a depth of ~23 km, and propagated mainly towards SW. The slip is concentrated in two asperities, confined in the depth range from 13 to 25 km. The peak slip is of the order of 60 cm and was reached at a distance of ~ 10 km to the SW of the rupture initiation. The slip model provided synthetic seismograms which matched satisfactory the observed. Forward modelling was used to calculate the ShakeMap for the mainshock. The 2015 Kasos earthquake provides evidence that the mode of deformation in the eastern part of the Hellenic subduction is taken up by the simultaneous operation of reverse faulting and of minor strike-slip faulting, with slip vectors approximately aligned with the bathymetry.

ABSTRACT. In this study, we applied Local Earthquake Tomographic Inversion in order to investigate the detailed 3-D structure within and around the broader region of Western Corinth Gulf, one of the most seismically active regions in the world. Data from the 2012-2014 time-period were used, selecting more than 2,000 seismic events, recorded by the local seismic stations of Hellenic Unified Seismological Network (HUSN) and the Corinth Rift Laboratory Network (CRLN). By the application of Tomographic Inversion, the production and interpretion of 3-D models of Vp, Vs and Vp/Vs ratio in the study area was feasible in order to show several distinct structures, namely areas of high and low Vp/Vs ratio, correlating the hypocenter distribution with changes in lithology or fluid concentration. In the area of Patraikos Gulf, an ascending velocity volume was traced that could possibly be connected to salt tectonics in the alpine basement, effecting the fluid circulation as well as the behavior of local faults.

ABSTRACT. On the basis of all available information eight circular seismogenic sources, where shallow (h 100km) earthquakes occur, are defined in the broader Aegean area. The location of each source is further improved by optimization of the quasi-periodic properties of the strong (M≥6.0) instrumentally recorded mainshocks, identified in a complete catalogue of earthquakes (1911-2014) after declustering. Moreover, in the same seismogenic sources, all M≥6.3 mainshocks that comprise another complete catalogue (1850-2014) have also occurred. Interevent times of mainshocks gener-ated in each source have predictive properties expressed by the TIMAPR (Time and Magnitude Predictable Regional) model whereas preshocks of recent mainshocks have also such properties expressed by the D-AS (Decelerating-Accelerating Seis-micity) model. Retrospective prediction of the last mainshock in each source by the joint application of the two models resulted in reasonable uncertainties. Then, as a forward test, data up to the end of 2014 were used to predict the next expected mainshock in each of the eight sources and to identify the fault where its epicentre will probably be located.

ABSTRACT. During a 12-month period (August 1998 - June 1999), a dense microseismic network of 44 portable seismographs, was installed in Epirus – Northwestern Greece, by the Seismological Laboratory, of the University of Patras and recorded 1368 earthquakes. We selected a subset of 200 well recorded events, with duration magnitude ranging from 1.61 to 2.92 and focal depths ranging from a few hundred meters to 35km; the majority was in the 0-10km range. This study uses this high quality dataset to (i) calculate the earthquake spectra and source parameters; (ii) perform linear regression between Seismic Moment (M0) and the source parameters Source Radius (r), Stress Drop (Δσ) and Displacement (s); (iii) correlate source parameter’s distribution with the tectonics of the area. Finally, we compare the derived empirical laws with similar studies.

ABSTRACT. The Electrical Resistivity Tomography (ERT) method was used in order to study the karstic system in Pedini area (close to the city of Ioannina, West Greece) that is re-lated with sinkholes whereby the drainage of the surficial water was possible. The last five years floods are causing major problems in the area, since, the urbani-zation of the basin, in which the construction of a large highway is included, along with the increase of rainfalls produced a huge amount of water which the sinkhole was not able to drain any more. The geophysical survey showed that the depth of the sinkholes is about 30 meters, proving their limited capacity to drain the basin to the desired level. At the same time, a fractured zone of high porosity has been revealed in the vicinity of the sink-holes.This zone can be used as to increase the capability of the sinkholes to drain the flood water.

ABSTRACT. This study presents sedimentological and palaeontological data retrieved from a coastal lagoon near Ayvalik in NW Turkey. The objective of this study is to inter-pret the depositional environments and reconstruct the evolution of the study area during the late Holocene. 42 sediment samples have been retrieved from a 13m core. Sedimentological analyses such as grain size analysis, moment measures of mean, sorting, skewness and kurtosis, definition of total organic carbon (T.O.C.), total nitrogen (T.N.), colour and CaCO3 (%) were employed. Moreover, macro and microfossils were collected to reconstruct the depositional environments. The palaeoecological analysis indicated a closed shallow shelf environment that gradually turned into a lagoon with a good communication with the sea. Radiocarbon datings from three samples indicate that these changes started taking place around 600 years BP to 4050±30 years BP.

ABSTRACT. A total of 27 samples of the Moschopotamos area lignite-bearing strata were studied in regard of their geochemical and sedimentary characteristics. Organic content and calcium carbonate evaluation, sieve analysis and micropaleontological observations were used and combined to investigate the paleoenvironment and the depositional conditions of the study area. TOC analysis showed that organic matter values range from 0.07% up to 13.42% with an average of ~3.26 %. The high average of organic carbon content indicates a promising basis for the sediments’ source rock potential, inquiring further and thorough examination. CaCO3 measurements present a range between 4% and 23%. A comparison between TOC-CaCO3 content throughout the stratigraphic column presented certain synchronous and inverse trends, due to alterations of the depositional conditions. This study provides new insights for the understanding of the broader Axios-Thermaikos basin, and depositional conditions in the North Aegean area.

ABSTRACT. A total of 80 samples of the Miocene deposits in Agios Georgios Pagon (NW Corfu) were selected and studied in regard of their geochemical and sedimentological characteristics. Organic content and calcium carbonate measurements were used and combined to investigate the depositional conditions and preliminary source rock potential. TOC analysis presented significant values ranging up to ~3% of organic carbon, with an average of 0,7%, and thus providing a promising basis for further assessment of their source rock potential. Calcium Carbonate measurements presented an average of ~27%. Fluctuations, correlative trends and the combined use of sieve analysis provide insights and alterations in the depositional conditions. The studied strata are part of an ongoing investigation throughout the Miocene to Pliocene sediment accumulations in Corfu, from Lefkimmi in the SW part to Agios Stefanos to the NW. The depositional conditions and source rock potential should provide new insights in understanding the geotectonic processes and basin development in the western margin of the Hellenic Fold and Thrust Belt.

ABSTRACT. The Corinth rift is counted among the most active tectonic grabens in the world, with extension rates up to 15 mm/yr (Western part). These high extension rates are associated with very strong seismic events that are, occasionally, responsible for submarine mass movements. These movements, their consequential bottom currents, and the differential river-discharging sediment accumulation in the whole gulf, strongly affect the modern marine sedimentary processes. The definition and understanding of these processes is the main aim of this project. This is attempted through via sedimentological, mineral and geochemical analyses on sediment samples from two ~1.1 m long, sediment cores from a WE submarine canyon (10 km long, 3 km wide) that lies in the Western tip of the gulf. The general sedimentation motif reveals the presence of hemipelagic deposits which are occasionally interrupted by sandy turbidites. Occasionally, these turbidites seem to have seismic origin. The sedimentation rates range between 2.57 mm/yr in the western part and 0.67 mm/yr in the eastern part.

ABSTRACT. An extensive oceanographic survey was conducted in the marine area between Kimolos and Sifnos Islands, a rather poorly-studied sector of the Aegean Sea, to gain better understanding of submarine geomorphological features and associated sediment provenance. Multi-beam bathymetry and surface sediment sampling with a box corer were carried out on board R/V Aegaeo, followed by grain-size, XRD and XRF measurements. A large circular depression was identified north of Kimolos reaching a water depth of 743 m, filled with fine-grained sediments. Surface sediments distribution is characterized by gradual decrease in grain-size from silty sand to silt in a S-N direction. The mineralogical composition comprises calcite, Mg-calcite, aragonite, dolomite, quartz, K-feldspars, plagioclase, amphiboles and clay minerals. Major sediment provinces identified were: (i) the shallow sector proximal to Kimolos, characterized by higher contents in Si, Al, K, Rb and Ba; (ii) the deep area west of Sifnos, including the large depression, characterized by higher contents in Fe, Ti, Na, Mg, S, Cr, Cu, Ni, V, Zn; and (iii) the south passage between Kimolos and Sifnos, which exhibits higher Ca, S, and Sr contents. Manganese enrichment was observed in and around the bathymetric depression, where Mn oxides act efficiently as scavengers of a suite of metals.

ABSTRACT. In this paper we discuss the landscape evolution of the Aggitis River basin by corre-lating the morphological characteristics of the Maaras Cave (Aggitis River spring) with the main geomorphological features of the Aggitis fluvial valley. We combine the various morphological features that are hidden inside the Maaras Cave with the surface geomorphology of the river valley in order to trace the imprint of the differ-ent evolutionary stages on the landscape. Also, we provide a relative chronological framework for the evolution of the area. The 3D survey of the Maaras Cave shows that the roof of the cave is looping-like shaped in contrast to the floor of the cave that shows low slopes and holds thick clastic sediment deposits. Furthermore, the geomorphological mapping of the Aggitis River valley shows two prominent wind-gaps at the southern part of the basin that formed as the result of river capture. Our results suggest that the Aggitis River basin suffered four major evolutionary stages from the Neogene until the Quaternary.

ABSTRACT. There are many systematic studies of stable isotopes in speleothems used to get proxy records of past climate changes in the Mediterranean region, as well as in Europe. This research emphasizes the importance of understanding cave atmosphere and hydrology in order to select suitable stalagmites for paleoclimate analysis. Since the isotope composition of the speleothem depends on the cave drip water content, which itself reflects soil and atmospheric settings we performed interannual monthly cave monitoring. Microclimate elements (air temperature and relative humidity) were measured and drip water and rain is collected in three Croatian caves during the 1-year period. The aim was to evaluate the influence of parameters such as temperature and rainfall amount on variability of oxygen isotope ratios and to determine potential sites for further paleoclimate studies. Moreover, we focused on caves on various altitudes (Strašna peć Cave on Dugi otok Island (70 m a.s.l.), Manita peć Cave in Velika Paklenica canyon (Velebit Mt, 570 m a.s.l.) and Spilja u Zubu Buljme Cave (Velebit Mt, 1305 m a.s.l.) to estimate contemporary regional and local influences of Atlantic and Mediterranean air masses and differences between coastal and continental, and between low- and high-altitude sites. Altitude effect was noted both in precipitation and in dripwater isotopic composition. Dripwater isotopic values cluster along the local meteoric water line (LMWL), whereas, in spite of the altitude difference, Manita Peć cave resembles the Strašna peć Cave record both by the slope and intercept. Both caves recorded low temperature variations and stable cave environments. Recorded dripwater intensities showed different hydrological regimes, while drip sites showed stable discharge mode with weak response to the rain events. The highest Spilja u Zubu Buljme Cave significantly differs from abovementioned caves by quite large temperature amplitude (5.3 °C), the lack of recent carbonate precipitation and expressed altitude effect on isotopic composition of rainwater. Such results indicate that Strašna peć and Manita peć caves are suitable paleoclimate study sites regarding cave climate and drip hydrological settings. We presume that speleothem calcite in these cave has been precipitated in isotopic equilibrium with dripwater which is crucial for accurately interpreting climate proxies contained within individual stalagmites.

ABSTRACT. Nesquehonite, a hydrous carbonate with promising uses such as building raw material and treatment of wastewaters, was synthesized under low pressure conditions by reaction of gaseous CO2 with Mg chloride solution and it was studied by means of X-Ray Diffraction, optical and scanning/transmission electron microscopy, and FT-IR and Raman spectroscopic methods. Synthesized nesquehonite forms elongated fibers, exhibiting transparent to translucent diaphaneity and vitreous luster. It is characterized by high crystallinity. IR and Raman spectroscopy indicated the presence of OH- and HCO3- in the crystal structure of nesquehonite. The nesquehonite synthesis described herein constitutes a potential permanent storage of CO2 emissions.

ABSTRACT. Nutritional habits have as a result the uptake of the elemental content of various foods in the human body. Salt (NaCl) constitutes an integral part of human diet needs. As a consequence, knowledge concerning the composition of edible salt is critical. The aim of the present study is to evaluate the components of 8 edible salt samples that are available in the Greek retail market. Samples were classified according to their colour as follows: white (WS1, WS2), black (BS1, BS2), pink (PS1), red (RS1), blue (BLS1) and pale brown (BRS1). The research revealed that all samples mainly consist of Cl and Na. Himalayan Black Salt (BS2) also contains S, whereas the Hawaiian Red Salt (RS1) contains Fe. Additionally, most of the samples contain low levels of Al, Ca, K, Mg, P, S, Si and O as impurities. Concerning the morphological characteristics, salt particles appear irregular, rounded and in two cases as cubic crystals referring to the crystal structure of NaCl. Backscattered images confirm the presence of other mineral phases besides NaCl.

ABSTRACT. Emplacement of the Xanthi Plutonic Complex within the Rhodope Massif of N. Greece created an extensive metamorphic aureole around the plutonite. The aureole contains two areas of intense scapolitization in the contacts between granodiorite and biotite-gneiss and between monzonite and sandstone, the latter cross-cut by andesite dykes. This paper reports the results of a mineralogical and geochemical study into the formation of the scapolites and particularly the nature of the plutonite-derived hydrothermal fluids from which scapolites were formed.

ABSTRACT. The use of standard estimation and modelling software tools in estimating marble quarry reserves poses a number of challenges. Marble quarry reserves are based on marble quality categories, almost unique for each quarry/deposit considered. These categories represent visual and physical aspects of marble such as colour, texture and fractures. Classification of marble to one of the categories is performed by experienced personnel and is based on samples much smaller in area than the blocks of marble which are potentially exploited. The available information is, also, mostly qualitative leading to further complications in the application of geomathematical estimation methods. The estimation of marble reserves described in this paper is based on interpolating quality indicator values from drillhole and quarry face samples to blocks in three dimensions. The procedure is applied in all working quarries of Iktinos Hellas SA and is based on Maptek Vulcan Quarry Modeller, a mine planning package adapted for quarrying. Its application and results is demonstrated using a case study from one of the quarries in NE Greece.

ABSTRACT. Greece has a very complex geodynamic setting deriving from a long and complicat-ed geological history being characterized by intense seismic activity and enhanced geothermal gradient. This activity, with the contribution of an active volcanic arc, favours the existence of many gas manifestations. Depending on the prevailing gas species, the latter can be subdivided in three main groups: CO2-, N2- and CH4-dominated. In the present work, we focus on methane and light hydrocarbons (C2-C6) to define their origin. CH4 concentrations (<2 to 915,200 μmol/mol) and isotop-ic ratios (δ13C -79.8 to +16.9 ‰, δD -298 to +264‰) cover a wide range of values indicating different origins and/or secondary post-genetic processes. Samples from gas discharged along the Ionian coast and in northern Aegean Sea have a prevail-ing microbial origin. Cold and thermal gas manifestations of central and northern Greece display a prevalent thermogenic origin. Methane in gases released along the active volcanic arc is prevailingly abiogenic, although thermogenic contributions cannot be excluded. Gases collected in the geothermal areas of Sperchios basin and northern Euboea are likely affected by strong secondary oxidation processes, as suggested by their highly positive C and H isotopic values (up to +16.9‰ and +264‰ respectively) and low C1/(C2+C3) ratios.

ABSTRACT. The paper presents data about the macroscopy lithotype and petrographic composition of Neo-gene lignites from Kosovo deposit. Lignite – particularly its fragmental pattern – can be de-scribed in terms of the properties of sedimentary rocks (Griffiths 1967, Skaberne, 1980). Accord-ing to this concept, lignite may be axiomatically defined as an aggregate of its macerals. Petro-graphic heterogeneity of coals is studied macro and microscopically in terms of lithotypes, microlithotypes and macerals. Composition of the SW Sibovci lignite was investigated on the basis of five vertical sections in open- pit mines. According to the ICCP recommendations (1993) and with some specific supplements, the SW Sibovci lignite can be also described by the following features: • Ratios between fine-detrital matrix and xylitic fragments • Size, shape, orientation and arrangement of coal components • Degree of gelification • Structural characteristics (lamination, bedding, banding) • Colour, fissuring, fracturing, jointing, hardness, brittleness, toughness. The rank coalification of the lignite is carried out by the field observations in the exploitation sectors and the study of samples. The interpretation of rank is carried out considering their chemical (contents of C, H, S, N, O), petrographic (reflectance of Huminite) and technologic analysis (moisture content, calorific power, volatile substances, ash content). Considering the rank of coalification, the lignite from Sibovci (Kosova) are classified as from transitory zone PET-LIGNITE.

ABSTRACT. A paleoseismological analysis has been performed at the East Giouchtas Fault. This fault dips to the east and represents a pure normal fault. The East Giouchtas Fault forms an intrabasinal high in the Heraklion basin with its conjugate fault the West Giouchtas Fault. A natural surface has been prepared and logged in detail in order to detect the most significant parameters related to the ground shaking impact on the area. Investigating past earthquakes characteristics attributed to the East Giouchtas Fault and through sample dating we conclude that the studied fault is related to at least four strong events of 6.4 magnitude. The fault is also characterized by 20-40 cm tectonosedimentatry displacements and slip rates of 0.25 mm/yr. Thus, the proximity of the fault to the highly populated Heraklion city and Minoan Knossos monument urges the need for an adequate hazard assessment of the area.

ABSTRACT. Two paleoseismological trenches were excavated across the Gyrtoni Fault in NE Thessaly and studied in order to understand the recent seismotectonic behavior of this structure. Twenty five fluvial-colluvial sediment and pottery samples from both the upthrown and the downthrown fault blocks were investigated. Optically Stimu-lated Luminescence (OSL) dating has been applied to date both sedimentary depos-its-palaeosoils and pottery fragments. Paleoseismological analysis of the two trenches indicates evidence of three surface faulting events in the time span be-tween 1.42 ± 0.06 ka and 5.59 ± 0.13 ka. The observed vertical displacement per event of ~0.50 m corresponds to an Mw 6.5 ± 0.1 earthquake. An average fault slip rate of 0.41 ± 0.01 mm/yr and an average recurrence of 1.39 ± 0.14 ka for earth-quakes were estimated. The results documented the activity of the fault and since the return period from the most recent event (minimum age 1.42 ± 0.06 ka) has ex-pired, the possibility for reactivation of this active structure in the near future should be included in Seismic Hazard Assessment.

ABSTRACT. The study examines a semi-quantitative indicator based method to assess the spatial susceptibility of archaeological sites to the secondary Earthquake Environmental Effects (EEEs) of ground liquefaction, landslides and tsunami. The method was applied at 16 archaeological sites allowing the identification of the EEEs each site is susceptible to and their prioritization at a national and regional level through the Spatial Susceptibility index (SSi). Results indicate that the majority of the sites are susceptible to at least one Earthquake Environmental Effect. This highlights their contribution to the vulnerability of archaeological sites to earthquake hazard and the necessity for the integration of spatial susceptibility parameters in vulnerability assessment studies for cultural heritage protection.

ABSTRACT. In this paper we defined the local complex fault system of the Cephalonia three strongest earthquakes (Mw6.1, Mw5.3 and Mw6.0) of the January-February 2014 se-quence and the Lefkada mainshock (Mw6.4) on November 17, 2015, in order to in-vestigate the fault interaction i) within the 2014 sequence, ii) between the 2014 se-quence and the fault that produced the 2015 Lefkada event, and iii) the cumulative effects of all Cephalonia and Lefkada strong events on other neighbouring faults, by calculating the static stress changes. The Coulomb stress change calculations suggest a complex distribution pattern on most of the cases, with only exceptions the F4 fault (Lefkada earthquake), which seems to be barely loaded with stress af-ter the Cephalonia 2014 events, and the “Assos-Skala” fault, which seems to be stress relieved after all Caphalonia 2014 and Lefkada 2015 events.

ABSTRACT. On Tuesday, November 17, 2015 at 07:10:07 (UTC) a strong earthquake struck Lefkas Island (Ionian Sea, Western Greece) with magnitude Mw 6.4, depth of about 7 km and epicenter located 20 km southwest of Lefkas town. The seismic activity in the region was essentially expected after the 2003 Lefkas earthquake and the 2014 Cephalonia earthquakes. Between these earthquake affected areas, the tectonic stresses were not released after the 1948 Lefkas earthquakes. Instead, they were in-tensifying and accumulating until the generation of the 2015 event. It was felt in Lefkas and the surrounding region and caused the death of 2 people, the injury of 8 others, earthquake environmental effects (EEE) and damage to buildings and infrastructure. Secondary EEE were observed in western Lefkas and included ground cracks, slope movements and liquefaction. Primary effects were not detected in the field. Buildings damage were mainly observed in villages of Dragano-Athani graben in southwestern Lefkas. Among structures constructed with no seismic provisions, the stone masonry buildings and monumental structures suffered most damage, while the traditional buildings with dual structural system performed relatively well. Reinforced-concrete buildings were affected not so much by the earthquake itself but by the generation of secondary effects.

ABSTRACT. The 17th November Mw=6.4 shallow event occurred along a N20±5°E strike-slip fault with right-lateral sense of slip. The earthquake caused a lot of structural damage to the villages of Agios Petros, Athani, Dragano and Komilio, all located in south Lefkada island. Environmental effects include liquefaction, extensive rock falls and landslides. No surface ruptures were found in the field. Road cracks are interpreted as secondary phenomena of gravitational nature induced by ground shaking. The value of the macroseismic intensity ESI-07 was assessed as VIII-IX. The documentation of the earthquake-induced environmental effects was realized using the Earthquake Geo Survey App. (for Android OS).

ABSTRACT. On November 17, 2015 a strong, shallow earthquake, Mw 6.5, occurred on the island of Lefkada along a strike-slip fault with right-lateral sense of slip. The event triggered widespread environ-mental effects that were mainly reported at the south and western part of the island while moving towards the eastern part, the intensity and severity of these earthquake-induced deformations were decreased. Relocation of seismicity and inversion of geodetic data suggests that the seismic fault runs parallel to the west coast of Lefkada, along the Aegean – Apulia plate boundary. The earthquake measured Mw=6.5 using the PGD relation of Melgar et al (2015, GRL). The fault plane strikes N20±5°E and dips to east with an angle of about 70±5 degrees. Coseismic defor-mation was measured in the order of tens of centimeters of horizontal motion by continuous GPS stations of NOANET (the NOA GPS network) and by InSAR (Sentinel 1A image pairs). Released interferograms from various groups show a large decorrelation area that extends almost along all the western coast of Lefkada, observation which provides strong support of landsliding. A coseismic slip model was produced from inversion of the ascending InSAR. We have not observed significant vertical motion of the shoreline and this is consistent with the predictions of the model.

ABSTRACT. The study "3,000 Years of East Mediterranean Sea Levels" investigates whether trends observed during this period in Israel from archaeological indications can be corroborated and strengthened by comparing them with relative sea levels observed in Greece. The process is comprised of three questions: 1) What types of archaeological sea-level indicators in Greece and Israel have the highest level of reliability for dating and sea-level evaluation? 2) What are the overall trends of sea-level change in Greece and Israel during the last 3,000 years, and what degree of error do these curves have? 3) What if any regional trends can be identified from the combined Greek and Israeli data? To answer the above questions, three objectives are pursued: 1) Identify archaeological RSL indicators of the last 3,000 years in Israel and Greece, including already published indicators with adequate measurements, those published but in need of new measurements, and unpublished potential indicators. 2) Assess the reliability of indicators using a consistent scoring system, correction for isostatic and tectonic effects, more precise measurements from indicators, and by exploring new methods to determine the chronology of rock carved indicators in Israel. 3) Using the assembled data, create a sea-level reconstruction for Greece, and combine the data with existing reconstructions from Israel for an analysis of matching trends. The study began with research of published sources and was supplemented by field activity. Surveys in Greece including Crete to assess both published and potential indicators occurred. Ruins from Chersonisos and Matala in Crete were examined and new measurements were taken from the latter. Fieldwork was also performed in Israel, including measurements from Caesarea for functional elevations on water channels at the promontory palace pool, at Achziv's fishpond, and around Tel Dor. The survey collected nearly 140 indicators from Israel and about 120 from Greece (excluding those outside the project's chronological scope). Of the Israeli indicators, some 120 were deemed reliable enough for reconstructions, whereas in Greece only 40 were, and not all of these from tectonically stable areas. The higher reliability of the Israeli dataset may stem from a smaller coastline and more focused sea-level research over the past few decades. In Greece, many measurements were taken by archaeologists in the 20th century before precise surveying methods were available, and published without sufficient metadata. Since then some of the sites have also become inaccessible to sea-level researchers. Analysis of indicators revealed gaps and disparities between the two regional datasets. Israel has a very strong set of many indicators from the Roman Period (~2000BP) to present, but fewer from 3000-2000BP. Greek indicators are strongly clustered in the Classical and Hellenistic Periods (2500-2000BP) with fewer before or after. These disparities make it difficult to effectively compare sea level between regions, but results suggest some correspondence of the curves. Analysis supports the work of previous Israeli researchers and suggests a relatively stable sea level there for the last 2000 years, with possible fluctuations not exceeding half a meter above or below current sea level at ~1500BP and ~750BP respectively. Both regions indicate a sea level rise between 2500-2000BP, but more data from Israel is needed to confirm this, while data from 3000-2500BP in Israel and Greece alike is scarce. In addition to the overall regional RSL comparisons, the current study also identifies the need for ongoing research and data collection: Continuing the search for sea-level indicators in Israel from 3000-2000BP, and in Greece from 3000-2500BP and from 2000BP to present, particularly in areas of reported tectonic stability like the Cyclades.

ABSTRACT. In this research, the geomorphological and environmental changes of Lake Ismarida during Holocene are studied. Ismarida is located 20Km south of Komotini city and 5Km NNE of the archeological site of ancient Stryme at Rhodope Province, (N. Greece). The analysis of geomorphological, paleontological, sedimentological and magnetic susceptibility data as well as the evaluation of 14C datings, showed that four environmental units are recognized in the lake sediments. The environment changed from shallow marine to open lagoonal of low energy (~5400-3400 years BP), to shallow marine to open lagoonal of high energy (~3400-3000 years BP), subsequently turned into brackish to lagoonal with fresh water inputs (~3000-2000 years BP), and finally formed to fluvial-terrestrial, until present time. The Lake Ismarida as it is known today was formed 2000 years BP on the isolated western part of the pre-Holocene valley between the deltaic deposits of the rivers Filiouris and Vosvozis.

ABSTRACT. The joint application of benthic foraminifera, pollen and non-pollen palynomorphs (NPPs), molluscs and magnetic susceptibility analyses in Piraeus coastal plain deposits resulted in the detailed study of palaeoenvironmental evolution of the area during almost the last 9000 years and the distinction of five lithostratigraphical-paleoenvironmental units and subunits. Combined results of our analyses features the occurrence of an inner lagoon (unit Aa) followed by an open lagoon (Unit Ab) depositional environment that was transformed to a shallow marine paleoenvironment with lagoonal features (Unit B) after 7800 BP. Since about 4800 BP a closed oligohaline lagoon (Unit C) used for grazing, occurred in the area, while after 2800 BP a marshy oligohaline depositional environment (Unit D) and signs of intensive agricultural activities are evidenced. The very good correlation of benthic foraminiferal, palynological, molluscan and magnetic susceptibility data and resulted indices is indicative of the potential of the applied methodologies as a paleoenvironmental tool box.

ABSTRACT. Beachrocks represents a coastal deposition in the intertidal area, and studying their properties may lead to create a model which identifies the conditions of their forma-tion (paleo-environment). This paper focuses most intently on the cement material which is able to recover the paleo-environment conditions during diagenesis of such coastal sediment. We used optical microscopy, secondary electron microscopy and Raman Spectroscopy to characterize the cement texture, mineralogy and chemistry in the beachrocks. The existence of pure calcite primarily controlled by the meteor-ite water, while Mg-calcite appears between the lower meteoric and the upper ma-rine phreatic zone. Finally, the presence of aragonite associated with the marine phreatic to lower marine vadose environment.

ABSTRACT. The oscillations of coast line in Albania, and simultaneously the Quaternary depo-sits in Albania were little studied until the decade of 90th of 20th century. Up to now, the studies consider those deposits as fluvial sediment; meanwhile, the coast line was categorized as of erosional and accumulative type. In those studies, the role of sea waves and euastatic change of sea level in the process of sediment supply in coastline is neglected. Transgression and regression was interpreted according to Theory of Geosynclinals, as tectonic subsidence or uplift of continental area. From observations in Borshi beach, during August 2013 and September 2015, result that the sediment in this area originate mainly from the erosion of coast line rocks, and less from sediments transported by continental flows. Some traces of marine sedi-ments inside the continental area, in a higher hypsometric quote regarding the ac-tual coastline traces of erosion in some infrastructure works dated of the decade 70’ and 80’ of 20th century, are argument of a temporal rise of sea level during the decade 90’ of past century.

ABSTRACT. Prominent geomorphological features of the shallow continental shelf west of the Kavala Bay (Loutra Eleftheron-Nea Peramos) were mapped-sampled using the data from a hydrographic survey (June 2014) of 320 nautical miles during which high-resolution multibeam bathymetry and seismic-reflection subbottom profiling were carried out simultaneously. A fault zone comprised by a set of two primary sigmoidal gravity faults, (recorded lengths and measured offsets: 12 km, 5 km and > 40 m, 25m, respectively), with distinct expression on the seabed, and three other secondary gravity faults situated southern of the major faults, revealing synsedimentary tectonics, was identified. The striking difference of the texture of the footwall block sediments of the northern major fault with the texture of the sediments occupying the deep hanging wall block of the southern major fault emphasizes the impact of local tectonics on the sedimentary evolution of the study area. Concerning the observed bedforms, the most interesting were the sand dunes occurring at depths from 25 m to 65 m at least and occupying the northeast part of the study area. Their large dimensions and orientation in relation to the coastline position imply as a mechanism for their formation intense bottom-current activity.

ABSTRACT. The study aims to evaluate soil erosion and investigate its spatial distribution by applying the empirical EPM (i.e. Erosion Potential Model) at mountainous Mediterranean type catchments. Study area includes the catchments of Venetikos; Kalamas; Upper Acheloos and Arachthos Rivers (eight subcatchments in total), very important aquatic systems of NW Greece. The model was implemented both annually and inter-annually. A GIS-based approach was adopted, considering the spatial variation of its factors, as well as the erosion processes occurring in a catchment. The results were initially validated by being compared to the observed sediment yield values (based on the sediment discharge measurements conducted by the PPC). The model’s performance was poor, significantly underestimating the results at both time scales. The ambiguous reliability of the PPC measurements led to their replacement by simulated ones, estimated using the sediment discharge rating curves methodology. Regarding the latter, the model performed better, attributing more accurate results, yet anew underestimated. However, it managed to identify the most susceptible to erosion areas. The poor performance is mainly attributed to its inherent shortcomings along with the specific characteristics and sedimentary regime of the study area.

ABSTRACT. Santorini metamorphic basement is part of the metamorphic complex Cycladic Massif, which was formed during the subduction of the Mediterranean lithosphere underneath the Aegean microplate. The two main components of the exposed basement are a complex of low-grade schists and phyllites, which are well exposed in Athinios harbour and underneath the crystalline limestones exposed in Mount Profitis Ilias and Mount Mesa Vouno. The Eocene and Miocene metamorphic units presented evidence of dynamic metamorphism, and possibly influenced by a granitic intrusion in Miocene. In this study, a new methodology was developed to study the two units exposed at Athinios. Structural data and rock samples were analysed using a Portable X-Ray fluorescence (PXRF) analysis at Athinios and integrated in a GIS (Geographical Information System) software to understand the spatial geochemical variations in the area. PXRF results for the two metamorphic units showed similar geochemistry patterns. However, a contour map of TiO2 (%) for the metamorphic rocks of the Athinios area presented intermittent zones of high and low TiO2 concentrations which could indicate hydrothermal remobilization of light elements and an enrichment in Ti. Petrography and geochemistry results suggest the local existence of a ductile-brittle shear zone between the two metamorphic units.

ABSTRACT. Intensity scales are used in order to measure the effects of an earthquake using the impact of the ground shaking on humans, man made environment and environment. The ESI-2007 is a new scale based solely on the earthquake-induced ground defor-mations, proposed by the INQUA Subcommission on Paleoseismicity. This scale has been translated in seven languages for a more systematic application. In this review article the new Intensity Scale is presented, as well as a brief of the earthquake case studies, occurred in Greece recently, in which the ESI-2007 was applied, is taken place. In addition, the definitions of intensity degrees are provided in Greek at the end of this article as appendix

ABSTRACT. The determination of recurrence time of strong earthquakes of certain magni-tude on a specific fault or fault segment is an important component of seismic hazard assessment. The occurrence of these earthquakes is neither periodic nor completely random but often clustered in time. This fact in connection with their limited number inhibits a deterministic approach for recurrence times cal-culation and thus application of stochastic processes is required. For recurrence times determination in the area of North Aegean Trough, all the available in-formation on strong earthquakes (historical and instrumental) with M6.0 is collected. Given that source parameters of historical events contain larger un-certainties, reassessment of their focal parameters before the application of sto-chastic processes is necessary, which was performed by applying the method of Bakun and Wentworth (1997). The reassessed catalogue was divided into three data sets, according to the strong events spatial distribution and their associa-tion with distinctive fault segments. Three statistical distributions (Weibull, in-verse Gaussian, lognormal) were applied and evaluated with the Anderson–Darling test and the Akaike and Bayesian Information Criteria. The Weibull dis-tribution exhibited better performance in two out of three data sets and the In-verse Gaussian distribution in the third. With given distributions the occurrence probabilities were calculated for strong events above a certain magnitude and for certain time interval.

ABSTRACT. Mylonitized manganiferous schists and calc-silicate layers intercalated within am-phibolite- to greenschist facies mica schists at Trikorfo area (Thassos Island, Greece), host an unusual Mn-rich paragenesis of metamorphic silicate minerals, most of them in very large, gemmy crystals. The silicates are present both in layers subparallel to the foliation, as well as in discordant veins crosscutting the metamor-phic fabric. Piemontite (up to 12.7 wt. % Mn2O3), Mn-rich epidote (up to 7.8 wt. % Mn2O3), Mn andalusite (up to 15.6 wt. % Mn2O3), Mn-poor pink clinozoisite-epidote (up to 0.87 wt. % Mn2O3), Mn-poor zoisite (up to 0.21 wt. % Mn2O3), spessartite (up to 47.7 wt. % MnO) and manganian grossular (up to 3.6 wt. % MnO) are minerals that formed after re-equilibration to post-peak metamorphic conditions and are as-sociated with diopside, hornblende, phlogopite, muscovite, tourmaline, hematite and iron-bearing kyanite. The studied assemblage is indicative of high fO2 conditions during fluid circulation along the Trikorfo shear zone, either due to mixing between magmatic, metamorphic and meteoric waters, and/or due to the presence of highly-oxidized pre-metamorphic Mn-rich mineral associations that was remobilized dur-ing the metamorphic event.

ABSTRACT. A previously undescribed tourmalinite rock consisting of tourmaline-rich veins and breccias occurs within the Lower Miocene Symvolon-Kavala granodiorite pluton, which intrudes the Lower Tectonic Unit of the Rhodope Metamorphic Province. Tourmaline, usually with crypto- to micro-crystalline grain size ,is abundant within the matrix of breccias, also forming along with quartz and host rock clasts massive veins and injections in the fractures of the pluton. Field relations indicate that the tourmaline veins and breccias most likely formed in a brittle deformation regime, overprinting the previously developed foliation of the pluton. In addition, miner-alogical and textural observations indicate that the precipitation of tourmaline was a result of cooling of B-rich hydrothermal fluids, implying for a possible mag-matic-hydrothermal origin for the studied tourmalinite.

ABSTRACT. The present paper presents new mineralogical and geochemical data of the siliceous sedi-ments from the region of Vasilika in northern Greece. The studied material consists of reddish and brownish cherts and jaspers containing mostly microcrystalline quartz and Fe-oxides. Chemical analysis has been carried out, including the identification of major oxides, trace elements and REE, in order to determine their geotectonic affinity based on the correlation of immobile trace element distribution. The geochemical features combined with the mineralogical composition of these siliceous sediments indicate that they were formed as the result of a hydrothermal circulating convection system near a mid-ocean ridge. Rare earth elements (REE) are regarded as the most reliable immobile elemental components in the complex geological process of the sedimentary cycle because they are relatively stable during post-depositional processes such as diagenesis, alteration and weathering. In addition Ce anomaly can help to establish the marine environment in which cherts were formed.

ABSTRACT. The Serpentinite between the chromite bodies 4 and 5 of Xerolivado mine (Vourinos, Greece), contains sparsely very small grains (<20μm) of awaruite (Fe0.91Cu0.06Co0.03Ni3), heazlewoodite (Ni2.91Fe0.06S2), magnetite and Co-pentlandite (Ni3.79Fe2.98Co2.38S8). The olivine contains 0.40 wt% NiO and 6.91 wt% FeO, while the serpentine 0.18 wt% NiO and 3.02 wt% FeO. The Co-content of awaruite is 1.31 wt% and that of heazlewoodite 0.12 wt%. Heazlewoodite is a product of the primary Co-pentlandite reduction, resulting from the serpentinization of the ultramafic rock. The Ni content of awaruite is derived both from olivine and from Co-pentlandite. The reducing environment resulting from serpentinization and the low sulphur fuga-city, favour the formation of awaruite, heazlewoodite and magnetite.

ABSTRACT. Sea level indicators, such as tidal notches and beachrocks, may provide valuable information for the relative sea level changes of an area. Beachrocks in particular have received various arguments concerning their use as reliable sea level indica-tors and their formation environment. This work focuses on the coasts of East At-tica in order to trace the palaeoshorelines of the Upper Holocene through the study of beachrocks. The coastal zone was surveyed in detail by snorkelling and diving, in order to locate, map and sample beachrocks. The samples were studied under a SEM, which showed that the beachrocks are mainly composed of quartz grains, a few calcites and feldspars, while the carbonate cement is characterized with the presence of MgO at percentages between 5 and 7.8%. Based on correlations with published drillings in the study area, the studied beachrocks should not be older than 2000 years BP.

ABSTRACT. Commercial marble are almost ready-to-use materials with a high economic value for the building-construction industry. The most important ornamental stones in Greece include limestone and marble with notable qualitative features and are considered as products of high commercial value. In this research, seventy-three carbonate samples (limestones, dolomites and marbles) from all over Greece have been studied so as to determine their macroscopic and petrographic features and to investigate their mineral chemistry and geochemistry. Their colours vary from whitish to gray due to their content of calcite and dolomite, black due to bitumens, yellow due to the presence of iron oxides and clay, red due to iron oxides and mixed phases of calcite- siderite, green-brownish due to the presence of iron oxides or muscovite and chlorite, giving a schist texture to the rock. Scattered calcite and dolomite veins, as well as the occurrence of other minerals such as barite, epidote and magnetite, contribute to specific features, thus making their appearance unique. The particular characteristics of each stone depend highly upon the type of minerals present, their modal composition and grain size, extent of aggregation, their geochemistry and their structural properties.

ABSTRACT. The aim of this study was to establish a chronological frame of paleoseismic events of Gyrtoni Fault, (Thessaly, Central Greece), with the use of OSL dating method. The Gyrtoni Fault, defines the north-eastern boundary of the Middle-Late Quaternary Tyrnavos Basin, and was previously investigated with geological methods. Twenty five fluvial-colluvial sediment and pottery samples were collected from two paleoseismological trenches, excavated along the Gyrtoni Fault, from both the up-thrown and the downthrown fault blocks. Optically Stimulated Luminescence (OSL) dating was applied to coarse grain quartz using the single-aliquot regenerative-dose (SAR) protocol. Investigations of luminescence characteristics using various tests confirmed the suitability of the material for OSL dating using the SAR protocol. Radioactivity measurements were preformed in order to estimate the annual dose rate of the surrounding soils to which the quartz grains were submitted during the burial period of the collected samples. The estimated OSL ages agreed well with the available stratigraphical data, and archaeological evidence. The occurrence of three surface faulting events in a time span between 1.42 ± 0.06 ka and 5.59 ± 0.13 ka was revealed while an earlier faulting event (fourth) was also recognized to be older than 5.59 ± 0.13 ka.

ABSTRACT. The Parnassus-Giona karst bauxite deposits contain significant concentrations of rare earth elements (400-500 ppm). Preliminary results from a pilot leaching study show that between 19 and 47% of rare earth elements in the bauxite are easily leachable using ion exchange agents such as ammonium sulphate.

ABSTRACT. The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and tremolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe-oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t).

ABSTRACT. The grain size distribution (GSD) of surface bed material in alluvial rivers is of in-terest in many geological, ecological and engineering applications. In this work, which is a part of our broader Ph.D research in Vouraikos river on sediment transport, we are testing the possibility of obtaining such a distribution from photographs taken at the field (grid sampling), compared with the standard method which is the “pebble count”. We have also examined and quantified the errors resulting from radial distortion of the photographs. The motive of the work was to explore the opportunity of substituting field work for laboratory work. Results show that for this method to give reliable results, a better knowledge of the site-specific conditions is needed, which, in turn, requires more field work.

ABSTRACT. The aim of the present study is to investigate the sedimentological characteristics of Lake Koronia down to a depth of 3.5m below lake bottom. Sampling operations took advandage of a season that the lake bottom was exposed to subaerial conditions. The sedimentological analysis proved that sediments consist of mud to sandy mud, with 2 phases of very fine sand fractions. The proportion of dry organic matter contained into sediment, appears to be generally small while the rates of moisture and volatiles are relatively high. Furthermore, this study examines the distribution of ostracod populations in the sediments of the lake in relation to depth, grain size and other environmental conditions of this water body. Four ostracod species were identified: Candona neglecta, Darwinula stevensoni, Heterocypris spp. and Limnocythere inopinata. The study of freshwater ostracods provides information for the palaeoecological/palaeoenvironmental conditions during the sedimentation.

ABSTRACT. Geological and geomorphological studies have been carried out in the western part of the southern coast of Patraikos Gulf and the findings were studied in relation to archaeological artifacts found in the same area. The characteristics of archaeological indicators and the deposits in which they occur, may indicate important aspects of their source, transportation way and age. The artifacts were found under present land surface in fluvial and alluvial deposits. Their age was estimated by archaeologists to be between 7th century BC and 4th century AC. Geomorphology and archaeology have strong historical and methodological links and can provide information about the processes and extent of environmental changes. They also provide the tools for analyzing sedimentation rates, relative chronology and geomorphological evaluation of the particular archaeological site as well as clues for land-surface development, paleoenvironmental and climatic conditions. Sediments indicating considerable climatic changes in current humid areas are alluvial deposits of considerable thickness, covering areas with human impact. There is a close correlation, as shown by the archaeological findings between climatic and environmental fluctuations. Since when there is a transition in climatic conditions causing changes in hydrologic conditions with ensuing geomorphological instability and burying the structures.

ABSTRACT. This paper is focused on the study of the South Cretan Margin, from a Digital Seabed Elevation Model, by employing Object Based Image Analysis. The goal is the automatic extraction of geomorphological and morphotectonic features based on morphological criteria and topological relations. A Digital Seabed Elevation Model of 150x150 meters resolution was employed. At first, slope, curvature, planform curvature, profile curvature and Topographic Position Index were derived from this DSEM. Five different layers of segmentation were created in order to extract the final geomorphological classes, Ptolemy trough, intraslope basins, main basins, small basins, continental shelf, plains, continental slope, escarpments, canyons, spurs, discontinuities, fault like and fault surface. The results were evaluated quantitatively, through the established indices Completeness, Correctness and Overall Quality. For computing these indices, it was necessary to digitize the boundaries of the objects derived by photo-interpretation. Then, the computation of the above indices, took place by comparing the results of digitized photo-interpretation boundaries, to the extracted feature boundaries through OBIA analysis (in shapefile). It is worth noting that, the results of the evaluation are quite satisfactory. Thus, the developed OBIA method is considered successful.

ABSTRACT. This paper is focused on the study of the North Aegean seabed, from a Digital Seabed Elevation Model (DSEM), by employing Object Based Image Analysis (OBIA). The goal is the automatic extraction of geomorphological features based on morphological criteria, in the North Aegean Basin. A Digital Seabed Elevation Model (DSEM) of 150x150 meters resolution was employed. At first, slope gradient, profile curvature, and percentile were derived from this DSEM. Four different layers of segmentation were created in order to extract the final geomorphological classes, discontinuities, faults like and fault surface in the final segmentation of level 4. On previous levels, more geomorphological features were also classified such as continental platform and continental slope. The results were evaluated qualitatively and quantitatively, through a tectonic map which has been created manually based on the analysis of seismic profiles. The results of the comparison of the two methods were satisfactory. Thus, the developed OBIA method is considered successful.

ABSTRACT. The area of interest is located close to Almyros city–at the prefecture of Magnesia (Central Greece), where the twin lakes Zerelia are situated. The origin of these twin lakes is not clear, however, many hypotheses have been proposed over the years. A lack of large-scale mapping in the surrounding area, and a high resolution spatial depiction of the topography, hinders the extraction of conclusions on the twin lakes' origin. Also, previous studies have focused on surficial evidence to support hypotheses, rather than investigating the geometric characteristics and the spatial lay-out of the twin lakes. Filling this gap, measurements of depth via sonar were performed in Zerelia lakes. The bathymetric data along with the digitized, high-resolution topographic data of the surrounding terrain were imported in a Geographic Information Systems (GIS) environment. The area was depicted with high accuracy through DTMs and conclusions for the landscape were extracted. The above analysis contributed towards an appreciation of the intense interplay between erosional and tectonic processes in the area, and deemed drainage antecedence as an important element that needs to be accounted for in any interpretation on the origin of the twin lakes Zerelia.

ABSTRACT. Tidal notches are a generally accepted sea level indicator that, when different from mean sea level, witness tectonic activity at or near coastlines. However, how to infer related information is controversial since tectonic uplift from a single seismic event is not likely to exceed several decimetres. High resolution laser scanning offers the availability of close-up views on exposures and to detect evidence for multiple sea level indicators in between major emergence. Statistically representative profiles along exposure were analysed in order to prove for already described tidal notches and to highlight similar shapes in consistent geometries along coastal cliffs of Perachora Peninsula.

ABSTRACT. The present paper summarizes the preliminary results of the micropaleontological and mineralogical analysis conducted on sediment samples from core TYR05 re-trieved from the anoxic and hypersaline Tyro basin in the eastern Mediterranean Sea. The core comprises a complex lithostratigraphic sequence attributed to the strong geodynamic regime of the area. The planktonic foraminifera associations present fluctuations which coincide with changes in the lithology of the core. The mineralogical composition of the sediment samples show influence of the brine de-veloped in the basin. The mineral components in association to the microfauna as-semblages suggests that the core sediments include sapropelic deposition. Further analysis is needed in order to determine safely the identification of the sapropelic deposits.

ABSTRACT. Metamorphic and igneous rocks of Terpnis' Serres of N. Greece have been studied. Nowdays these metamorphic rocks are used as raw materials in stone wool production, by Fibran industry, whilst the studied plutonic samples with lower content of iron oxide proposed as alternative raw material for the production new lightly colored stone wool, according to the market demands. Selected epidote amphibolites and quartz diorite samples were analyzed by ICP-ΟES, AAS, XRD, Petrographic microscopy, and SEM. The epidote-amphibolites show some evidences of weathering leading to sericitic-saussuritizated plagioclase crystals and secondary smectite and chlorite nanocrystals. Phyllosilicates affect positively the grinding procedure and melting of the raw materials under industrial conditions of stone wool production, due to its lower hardness and melting point than that of the primary hornblende. The chemical and major mineralogical composition, the heterogeneous characteristics of textures as well as the often phyllosilicates presence, due to the weathering of the plutonic studied samples, are expected to contribute to the easier grinding and melting of rocks under industrial conditions as well as to the production a new lightly color and competitive stone wool product.

ABSTRACT. Mantle xenolith samples in contact with basalt flows were collected from the Ta-fraoute maar in Morocco. Discrete melt veins are present in one xenolith sample, crosscutting primary layering and foliation. We used both optical microscopy and electron microprobe analysis to characterize the glasses and minerals in the melt veins. The melt veins consist of glass and crystals of olivine, clinopyroxene, plagio-clase, spinel and apatite. The olivine in the melt veins is quite distinct from the same mineral within the matrix due to its characteristic P-enriched rims (up to 0.3 wt.%). Correlations between Al and P, as well as experimentally determined partition coefficient for P, point towards non-equilibrium partitioning during rapid crystal growth at the end of crystallization.

ABSTRACT. This paper aims to present mineralogical and geochemical characteristics of zeolites hosted by plagiogranitic rocks from Tuci - Kimza region, Northern Albanian ophiolites. The plagiogranites, that represent the uppermost part of the plutonic section of the Albanian ophiolites, are intensively altered. They crop out in the north – eastern sectors of the Albanian ophiolitic complex having intrusive contacts with volcanic and gabbroic rocks. The zeolite, that is a typically secondary mineral, has filled thin veins and/or small vesicles of the rock. From XRD, EMPA and optical observation was found that zeolites belong to Laumontit – Leonhardite series.

ABSTRACT. On Nisyros as a result of the volcanic activity and active tectonic, a hydro-thermal system develops and it is expressed by 3 types of surface manifesta-tions: i) thermal springs, ii) fumaroles and iii) mudpots. In general, a mudpot could be described as an acidic hot spring or fumarole with limited water which forms in high-temperature geothermal areas. Water sample and depositions of mudpots collected, analyzed and studied from Stefanos hydrothermal crater, which is the only site on Nisyros Island, where mudpots occur. Mudpots water is very acidic (pH=2.4), with high sulfate concentration (1375mg/L), due to the H2S(gas) and temperature near the boiling point. As a result, elemental sulfur is found inside the depositions alongside with products of the hydrothermal alteration of the surrounding rocks. In the water and in the depositions were found high concentrations in several elements (e.g. in water: 55mg/L Fe; 19.5mg/L Zn, in depositions: 430mg/Kg Pb; 72mg/Kg Cu; 60mg/Kg Cr) reflecting the alterations processes which are taking place.

ABSTRACT. Tourism development in Greece has led to increasing pressure on coastal areas, which makes the study of sensitive coastal areas essential, in order to find appropriate solutions for their shielding. The aim of this study is an estimation of the effects of an anticipated sea level rise for the touristically developed part of Pieria Prefecture, which includes the settlements Paralia, Skala of Katerini, Olym-pic Beach, Korinos Beach and extends north to the area of the Kitrous brine and south to the mouth of the river Mavroneri. Therefore the Coastal Vulnerability Index (CVI) is applied, in an attempt to determine the susceptible parts to the potential sea level rise. CVI depends on the following parameters: (a) coastal geomorphology, (b) coastal slope, (c) shoreline erosion/accretion rate, (d) relative sea-level rise fluctuations, (e) mean tidal range and (f) the significant wave height. The classification of the coast, which is of particular socio-economic significance since it hosts urbanized areas, into five CVI classes (1|very low vulnerability to 5|very high vulnerability), showed that 43.6% of the entire coastline is of very high vulnerability.

ABSTRACT. On June 8, 2008, a Mw 6.4 earthquake occurred on a strike-slip fault in north-west Peloponnese, Greece, 35 km southwest of the city of Patras. We analysed part of the aftershock sequence of the 2008 earthquake, recorded by a portable network of six stations and a permanent station of the Hellenic Unified Seismological Network, in order to perform a shear wave splitting analysis. We determined fast polarization directions φ, and time-delays dt between the fast and slow components. The average value of dt was calculated at 1.7 ±0.5 ms/km, while φ values varied between 155 ±8 and 191 ±9 degrees, with an average of 170 ±9 degrees. The observed φ at all stations were inconsistent with the regional stress field, which is characterized-by a general E-W orientation of the maximum horizontal compressive stress. On the contrary, the observed fast directions appear to intersect the strike of the causative fault (210 degrees) in smaller angles than the regional principal compressive stress axis. The findings of this work are consistent with those of previous studies in the area, reflecting possibly the presence of a locally rotated principal stress axis to more favorable angles to the strike of the fault of the 2008 strong earthquake.

ABSTRACT. The Mid-Atlantic Ridge (M-AR), which runs along the centre of the Atlantic Ocean, is one of the best known divergent boundaries. Seismic studies have been a crucial factor in deciphering the structure of the oceanic crust. For their performance a necessary prerequisite is the compilation of a reliable earthquake catalog of the broader area. In this study, an attempt was made to create an earthquake catalog of M-AR that could become a useful “tool” for large-scale seismological studies of this region. For this reason a very large sample of data from several seismological centers, as well as from already published catalogs of strong earthquakes, was collected and examined. ISC was considered as the main reference agency, while as reference magnitude scale the moment magnitude scale, MW was adopted. The main goal was to identify and organize the best and most recent information available for earthquakes falling within the time window 1900-2014 and the space window bounded by the extended coordinates ~ 81 (N) to -51 (S) and 10 (E) to ~ -50 (W). After magnitude homogenization, check of focal depths and definition of completeness magnitude, a reliable and homogeneous earthquake catalog of M-AR consisting of 14,211 events was created, available for any seismological use and further study.

ABSTRACT. The conditional probabilities method is considered to be an alternative approach in order to estimate the earthquake hazard. For this purpose, this technique was applied to the western side of South America, one of the most seismogenic regions of the world. The method is applied in six pre-determined zones which covered the whole examine area. The occurrence of the earthquakes as a function of time was assessed, using the conditional probabilities technique. The Kolmogorov-Smirnov test was applied in order to determine the distribution followed by the inter-arrival times between the successive past events. The test shows that the lognormal is the best fit distribution, for the scope of the present work. The obtained results are in good accordance to the method applied. High probabilities are estimated for events with Mw>=7.0. For the whole western part of South America, there is a probability about 64% for an earthquake occurrence with magnitude M>=8.0, during a time period of 20 years. Higher probability (≈73%) was estimated for a time period of 50 years and for an earthquake of magnitude M>=8.5. This is clearly showed for the event of 1960, where the next (a posteriori procedure) earthquake of M=8.8 occurred on 2010.

ABSTRACT. Stress triggering must be incorporated into quantitative earthquake probability estimate, given that faults are interacted though their stress field. Using time dependent probability estimates this work aims at the evaluation of the occurrence probability of anticipated earthquakes near the city of Thessaloniki, an urban center of 1 million people located in northern Greece, conditional to the time elapsed since the last stronger event on each fault segment of the study area. The Bakun and Wentworth method is used to improve the existing earthquake catalog (from AD 1600 – 2013 with M≥6.0) in order to compute new interevent and elapsed time values which form the basis for time-dependent probability estimates. To investigate the effects of stress transfer to seismic hazard, the probabilistic calculations presented here employ detailed models of coseismic stress associated with the 20 June 1978 M=6.5 Thessaloniki which is the latest destructive earthquake in the area in the instrumental era.The combined 2015-2045 regional Poisson probability of M≥6.0 earthquakes is ~35% the regional time-dependent probability varies from 0% to 15%and incorporation of stress transferfrom 0% to 20% for each fault segment.

ABSTRACT. The main objective of the present study was to develop a landslide susceptibility model by combining Fuzzy logic and Information Theory in order to estimate the spatial probability of landslide manifestation, in the mountains of central Tzoumerka, Greece. Specifically, Fuzzy logic was enabled for weighting the landslide related variables based on expert knowledge and in respect to landslide susceptibility, while the Shannon’s entropy index, an index from Information Theory, was calculated to weight the significance of each landslide related variable based on the available data. The final landslide susceptibility map was produced by applying the weighted sum method. Engineering lithological units, slope angle, slope aspect, distance from tectonic features, distance from river network and distance from road network were among the six landslide related variables that were included in the landslide database used in the training phase. The landslide inventory map was constructed by interpreting aerial photographs, satellite images and field surveys and was separated into two datasets, one for training and one for validating the model. The outcomes of the validation process illustrated that the developed methodology efficiently provided the most susceptible areas and was in good agreement with the actual landslide locations. The area under the curve was estimated to be for the training and validating datasets 0.7575 and 0.7828 respectively. The produced landslide susceptibility map could be regarded from local and national authorities as a valuable mean to evaluate strategies or to prevent and mitigate the impact of landslides.

ABSTRACT. The main objective of the present study was to investigate ground subsidence in the wider area of Farsala, western Thessaly basin, by means of remote sensing tech-niques and to identify potential geo environmental mechanisms that contribute to the development of the observed surface fractures affecting the site. In this context, a set of Synthetic Aperture Radar (SAR) images, acquired in 1995–2003 by the European Space Agency (ESA) satellites ERS1 and ERS2 and processed with the Persistent Scatterer Interferometry (PSI) technique by the German Space Agency (DLR) during the Terrafirma project, were evaluated in order to investigate spatial and temporal patterns of deformation. Groundwater table levels of three water boreholes within the research area were processed providing the mean piezometric level drawdown and the mean annual drawdown rate. In addition, a quantitative comparison between the deformation subsidence rate and the thickness of the compressible sediments was also performed. The outcomes of the present study indicated a clear relationship in the subsidence deformation rate and the groundwater fluctuation and also a correlation between the depth of the bedrock and the deformation subsidence rate. Overall, the SAR interferometry (DInSAR) data are proved as a valuable and suitable technique for increasing knowledge about the extent and the rate of the deformations in the current study area, proved to be affected with an increasing intensity.

ABSTRACT. This paper concerns the study of the seafloor through digital seabed elevation models, using object based image analysis methods. The goal of this research was the automated extraction of geomorphological features from the seabed in regions presenting intense volcanic activity. The study area is located around the submarine volcano of the Kolοumbo (in the submarine area northeast of the Santorini island, Greece). For this purpose, a Digital Elevation Model (DEM) of the seabed with a spatial resolution of 50m was used. Derivatives of the DEM, such us Slope, Topographic Position Index (TPI) and Terrain Ruggedness Index (TRI) were created in the open source software "QGIS 2.4". The implementation of the object based image analysis approach was performed in eCognition 8.7 software. Nine segmentation and classification levels were created in order to produce the final level segmentation "level 5", where the final geomorphological features were classified. The results of the method were evaluated using classification stability measures and qualitative and quantitative comparison of the results with existing map.

ABSTRACT. Horizontal to Vertical Spectral Ratio (HVSR) method has been applied on ambient noise records at the Rio- Antirrio area (SW Greece). The dataset used was recorded by 12 seismic stations of a temporary seismic network deployed in the area. The stations were laid out along a profile and their interval was approximately 500 m and the main part of the processing utilized Geopsy software. The aim of this study was to estimate the fundamental frequency at the station sites and its variation with time and azimuth. Finally, estimations of top sediment layer’s geometry and thickness were made by approximating the values of Vs velocities from crosshole measurements.

ABSTRACT. A study on the aftershock sequences distributed along the subductions in Japan and Kuril islands, as well as in Kamchatka is undertaken. Aftershock sequences, having a main shock magnitude Mw >7.0, during the time period 1973 - 2013 are taken into account. The data used (mainshocks, aftershocks and foreshocks if there are any) are restricted in shallow focal depths. A large earthquake in Japan Trench (11 March 2011 / Mw=9.0) occurred and for this reason the investigated area is of particular interest. Our study is concentrated on the spatial distribution of some parameters [Mc, a, b (Gutenberg-Richter distribution) and p, c. k (Omori’s law)] closely associated with the seismic sequences statistics.

ABSTRACT. Rock magnetic and palaeomagnetic analyses on lithic clasts collected from the pumice fall deposited inside the archaeological site of Akrotiri have been applied in order to estimate the deposition temperature of the first volcanic products of the Minoan eruption. A total of 50 lithic clasts have been collected from four different locations inside the excavation of Akrotiri. All samples have been stepwise thermally demagnetized and the obtained results have been interpreted through principal component analysis. The equilibrium temperature obtained after the deposition of the pumice fall varies from sample to sample but generally shows temperatures around 240-280 oC. These temperatures are in good agreement with those estimated from lithic clasts from the Megalochori Quarry while they are higher compared with those from ceramic fragments from Akrotiri. The new temperature data presented here show that the pumice fall was still relatively hot when deposited inside the archaeological site and even if it interacted with the buildings, often causing the collapse of roofs, it still remained hot with mean temperature around 260 oC.

ABSTRACT. An anisotropic upper crust has been revealed in the W. Gulf of Corinth with potentially changing properties. During 2013, a unique opportunity to conduct a shear-wave analysis was presented, as a combination of the significantly increased seismicity in the area, including a seismic swarm between May and August, and the existence of local seismological networks. The Hellenic Unified Seismological Network (HUSN) and the Corinth Rift Laboratory Network (CRLN) provided invaluable data during the unrest period. While shear-waves travel through an anisotropic medium, the splitting phenomenon takes place and, as a result, their propagation is characterized by two discernible components: the fast (Sfast) and the slow (Sslow) one, which arrives to the station in a subsequent temporal point. Modern advances in seismology and geophysics have rendered shear-wave splitting a valuable tool in determining properties of the anisotropic propagation media. One of the predominant causes of this phenomenon is the existence of microcracks throughout the upper crust. The current study presents results for 8 stations from 535 analyzed events that are in agreement with the anisotropy models of EDA and APE.

ABSTRACT. On April 2007, an earthquake swarm occurred in the vicinity of the Trichonis Lake, western Greece. The seismic activity started on April 10th, 2007 after the occurrence of three moderate size earthquakes Mw 5.0-5.2. We performed shear wave splitting measurements on seismic events recorded during the first week of the seismic activity by a portable network of 8 stations that was installed in the area by the University of Patras Seismological Laboratory. We were able to take measurements from 5 stations as the seismicity was concentrated mostly at the eastern part of the lake. Two splitting parameters were measured through the data processing, the time-delays between the fast and slow shear wave components and the polarization directions of the fast components. In general, the data analysis revealed the presence of shear wave anisotropy in the study area. The average value of time-delays was calculated at 6.9 ±1.1 ms/km while the fast polarization directions had an average of 130o ±14o. The mean fast polarization directions were consistent with what is expected concerning the local stress field, as it was sub-parallel to the direction of the maximum horizontal compressive stress axis and almost perpendicular to the direction of extension. Therefore, the findings can be interpreted by an anisotropic volume of stress-aligned micro-cracks within the upper crust according to the extensive dilatancy anisotropy model.

ABSTRACT. The non-destructive methods are necessary in the investigation of the physical and mechanical properties of the materials in monuments. In this framework the ultrasonic velocities were used in situ for the elaboration and evaluation of the weathering on the surfaces of monuments. Additionally, the P-wave velocities were used for the estimation of the depth of weathered zone, as well as the depth of cracks at the surface of the monument. This estimation was performed on a Jewish tomb placed in the AUTH university campus between the building of Law and Economic Sciences and the Administration building, of the Aristotle University of Thessaloniki.