The Morphotectonic units of Ikaria island – Contribution in the natural hazards research

ενός μεν της διαχρονικής εξέλιξης της νήσου, όπως αυτή εντάσσεται στα πλαίσια της γεωδυνα-μικής εξέλιξης του ελληνικού τόξου και ιδιαίτερα κατά τα τελευταία στάδια από το Αν. Μειόκαινο και μετά, αφ' ετέρου δε της δράσης των εξωγενών παραγόντων, αλλά και της ανθρώπινης παρέμβασης.Με βάση τα πρωτογενή στοιχεία υπαίθρου και την ανάλυση, επεξεργασία και αξιολόγησή τους μέσα από τη χρήση νέων τεχνολογιών (χρήση GIS, ανάλυση γεωγραφικών και περιγραφικών δεδο-μένων) προσδιορίστηκαν για την νήσο συγκεκριμένες μορφοτεκτονικές ενότητες. Η διάκριση των μορφοτεκτονικών ενοτήτων διαφαίνεται μέσα από τα ιδιαίτερα χαρακτηριστικά τους και έγκειται τόσο στη λιθολογική διαφοροποίηση (γρανίτης, μεταμορφωμένα, μεταλπικοί σχηματισμοί) και στο διαφορετικό τεκτονισμό (ρήγματα αποκόλλησης, ρήγματα οριζόντιας ολίσθησης, κανονικά ρήγματα), όσο και στην ιδιαίτερη μορφολογία (κατανομή κλίσεων, ασυμμετρίες υδρογραφικού δικτύου, επιφά-νειες επιπέδωσης, μορφολογικές ασυνέχειες κλπ.).Η σύνθεση των ιδιαίτερων χαρακτηριστικών της κάθε μορφοτεκτονικής ενότητας σε συνδυασμό με την ανθρώπινη παρέμβαση (πυρκαγιές, ανεξέλεγκτη βόσκηση κλπ.), καθορίζει και το είδος, την ένταση και το γεωγραφικό εντοπισμό των φυσικών κινδύνων που εκδηλώνονται στις διάφορες περι-οχές του νησιού, όπως κατολισθήσεις, διάβρωση, πλημμύρες, σεισμική δραστηριότητα, μεταβολές αναγλύφου, μεταβολές ακτογραμμών κλπ.Present morphological and tectonic image of Ikaria island is the complex result of both the tem-poral evolution of the island, as part of the geodynamical evolution of the Hellenic Arc, especially that of the last stages (from the upper Miocene and after), and the exogenous factors. Also human impact functions as an additional parameter for the formation of Ikaria geoenvironment.According to field data and their analysis, computing and estimation which took part with the use of modern technologies (use of GIS, analysis of geographical and descriptive databases) the mor-photectonic units of Ikaria Island were defined. The definition of the morphotectonic units was based on their special features and more precisely on the lithological differentiation (granite, metamorphic rocks and post alpine formations) as well as the complex ductile and brittle structures (large scale ductile shear-zones and brittle detachment faults, normal faults, strike-slip transfer faults and join sets) and the morphological features (slope distribution, asymmetry of the drainage system, planation surfaces, morphological discontinuities etc).The synthesis of the special features of each morphotectonic unit in combination with the human impact (fires, overgrazing etc), defines the kind, the intensity and the geographical localization of the natural hazards which occur in various sites of the island, such as landslides, erosion, floods, seismic activity, relief changes, coastline changes etc

Late Holocene shorelines deduced from tidal notches on both sides of the Ionian Thrust (Greece): Fiscardo Peninsula (Cephalonia) and Ithaca Island.

Fossil shorelines produced by recent co-seismic movements were identified throughasubmarine survey along the coasts of Ithaca and Fiscardo (Greece).In both areas a tidal notch-slightly submerged below present Mean Sea Level (MSL) was observed at various sites. This “modern” notch is known to have been submerged by the global sea-level rise during the 19th and 20th centuries. The depth after tide and air-pressure correction of the vertex of the “modern” notch (that owes its submergence to the current rapid sea level rise) was measured between -20 and -30±5cm at Fiscardo and between -36 and -45±6cm at Ithaca. This “modern” notch at the same depth on east and west sides of the Ionian Thrust suggests that both areas were not affected by the co-seismic vertical movements that occurred in 1953 (in the wider area). On the other hand, a greater depth in Ithaca could be an effect of co-seismic subsidence. Over the long term, the tectonic behavior of Ithaca differs from Fiscardo. At Ithaca no evidence of emergence was found and Holocene vertical movements have been only of subsidence: submerged fossil tidal notches were distinguished below MSL at about -40 (modern), -60, -75, -95, -106, -126, -150 and -220±6cm. On the East coast of Fiscardo peninsula impacts of ancient earthquakes have left some marks of emergence at about +18 and +44±5cm, and of submergence at about -25 (modern), -45, -60, -75, -82, -100 and -230cm, with even some evidence of past uplift and subsidence at the same sites

Late Holocene tectonic implications deduced from tidal notches in Leukas and Meganisi islands (Ionian Sea)

In this paper the tectonic behavior of Leukas and Meganisi islands (Ionian Sea) is examined through underwater research carried out in both islands. A possible Late Holocene correlation between coseismic subsidences is attempted and evidenced by submerged tidal notches in both islands. These subsidence events probably occurred after the uplift that affected the northernmost part of Leukas around 4 to 5ka BP. In conclusion, although the whole area was affected by a similar tectonic strain, certain coseismic events were only recorded in one of the two islands and in some cases they affected only part of the study are

Центральная Азия в интересах Ирана, Китая, России и Турции: взгляд из США

Работа посвящена изучению реакции американских специалистов на внешнюю политику Ирана, Китая, России и Турции в Центральной Азии. В исследовании комплексно рассмотрена политика единственной сверхдержавы относительно отдельного региона в рамках общей стратегии США.Робота присвячена вивченню реакції американських фахівців на зовнішню політику Ірану, Китаю, Росії та Туреччини у Центральній Азії. У дослідженні комплексно розглянута політика єдиної наддержави щодо окремого регіону в рамках її загального стратегічного курсу.The thesis is focused on a study of the american specialists reactions toward foreign policy of China, Iran, Russia and Turkey in Central Asia. The research presents a complex investigation of the policy of the only superpower in the relation to a separate region in the frame of its general strategic course

Late Quaternary sea-level change and early human societies in the central and eastern Mediterranean Basin : an interdisciplinary review

This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates

Modelling of erosional processes in the Ionian Islands (Greece)

This paper focuses on the study of the geomorphological processes and the impact of neotectonic deformation on the geomorphological structure. A vast database was developed, containing different kinds of information, concerning geology, topography, drainage characteristics, vegetation and land use of the Ionian Islands. A geographic information system platform was developed in order to analyse the data, and to model and finally map the prevailing geomorphological processes: the erosion and deposition zones.Erosion risk factors have been processed in order to develop erosion risk maps demonstrating vulnerable to erosion areas. This study also concludes that the Ionian Islands are strongly influenced by the neotectonic processes that have defined their current morphology. © 2012 Copyright Taylor and Francis Group, LLC

GIS database for the geomorphological study of Paros Island

In this paper a geomorphological GIS-based database was developed under the MapInfo Professional environment in order to systematically store information such as the exact coordinates and the corresponding fields of each geomorphological element. Apart from MapInfo's internal database, Microsoft Access was used as an external database, connected to MapInfo, through ODBC drivers. Paros island (Cyclades/Greece) was used as a case study. This island has a variety of morphological characteristics, many of them formed as a result of its complex lithological and tectonic structure that enforce differential erosion processes. All primary data of this geomorphological study were acquired via photointerpretation and fieldwork supported by the combined use of GIS and GPS in order to increase the accuracy and to speed up fieldwork. GIS also provided the opportunity for further spatial and quantitative analysis of the geographical database and the creation of a GIS - based geomorphological map