E steiakakis | Technical University of Crete (original) (raw)

Papers by E steiakakis

Geosciences, Nov 22, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Geosciences, May 24, 2024

Case Studies in Chemical and Environmental Engineering

International Conference on Raw Materials and Circular Economy, 2022

Bulletin of the Geological Society of Greece, 2017

The purpose of this paper is to recognize inferred faults in Tympaki basin (Crete island) which c... more The purpose of this paper is to recognize inferred faults in Tympaki basin (Crete island) which cannot be observed on the surface, as the area is covered by recent deposits. The identification of the faults is crucial for the study of the sea-water intrusion in Tympaki basin that has been observed during the last years. 3D geological modelling techniques were used for reaching the aforementioned goal. The data used include the digital elevation model (DEM) of the area, the boundary surface between geologic formations and the litho - stratigraphic logs of thirty nine (39) wells. Initially a 3D stratigraphic model was set-up depicting the spatial extension of Plio-Quaternary and Neogene deposits. Next, with emphasis on the litho - stratigraphic logs of the wells, the boundary between the geological formations was defined in a 3D space. The regional unconformity between the Plio-Quaternary and Neogene formations is possibly the result of tectonic activity of inferred faults. The traces...

Bulletin of the Geological Society of Greece, 2016

One of the most important environmental problems in coastal areas is the salinization of ground w... more One of the most important environmental problems in coastal areas is the salinization of ground water. The groundwater contamination due to seawater intrusion is usually caused by a violation of a delicate hydrogeological balance that exists between freshwater and seawater in coastal aquifers. The development of a methodology for the prediction of the systematic sea water intrusion can contribute to the planning of effective prevention measures in the coastal areas. The geophysical techniques offer a suitable non-invasive method for determining the geometric characteristics of an aquifer and monitoring the saline water intrusion. Among all geophysical techniques, the most successful methods, concerning the detection of salinization in the coastal areas, are the electric resistivity and electromagnetic methods. Seismic methods can also help in providing further geological information for the stratigraphy. In this work, we present the preliminary results from the geoelectrical...

Proceedings, 2014

ABSTRACT A geophysical survey was conducted at Tybaki, Crete, Greece in order to support the geol... more ABSTRACT A geophysical survey was conducted at Tybaki, Crete, Greece in order to support the geological and hydrogeological studies of the existing phenomenon of seawater intrusion. This survey employed seismic refraction, transient electromagnetic (TEM) and geoelectrical methods. The later, consisted of Vertical Electrical Sounding (VES) and Electrical Resistivity Tomography (ERT). The objective of this survey was to image the saltwater intrusion at this area and map possible favorable sea water pathways. We present the combined interpretation of vintage geophysical data obtained under the research project MEDIS and the ClearWater project data. At Tybaki, the geophysical survey provided images of the saltwater intrusion which is present at the north west of the basin.

Geomaterials, 2012

The saturated hydraulic conductivity of a soil is the main parameter for modeling the water flow ... more The saturated hydraulic conductivity of a soil is the main parameter for modeling the water flow through the soil and determination of seepage losses. In addition, hydraulic conductivity of compacted soil layers is critical component for designing liner and cover systems for waste landfills. Hydraulic conductivity can be predicted using empirical relationships, capillary models, statistical models and hydraulic radius theories [1]. In the current research work the reliability of Kozeny-Carman equation for the determination of the hydraulic conductivity of compacted clayey soils, is evaluated. The relationship between the liquid limit and the specific surface of the tested samples is also investigated. The resulting equation gives the ability for quick estimation of specific surface and hydraulic conductivity of the compacted clayey samples. The results presented here show that the Kozeny-Carman equation provides good predictions of the hydraulic conductivity of homogenized clayey soils compacted under given compactive effort, despite the consensus set out in the literature.

Geosciences, 2018

Karst systems constitute valuable freshwater resources in Crete island, a region of Greece that i... more Karst systems constitute valuable freshwater resources in Crete island, a region of Greece that is threatened by water scarcity. The present work refers to evaluation of the available groundwater potential in a karst terrain and contributes to providing adequate quantities of fresh water to the central southern Crete (Rethimno prefecture). The available groundwater potential was estimated by combining conventional hydrogeological approaches and an analysis of hydrographs of Kourtaliotis spring that drains the system. The research procedure contributed to the three-dimensional understanding of the karst system and provided reasonable estimates regarding the groundwater reserves in the area. The geological (permanent) storage in the karstified system was estimated to 415 × 10 6 m 3 while the dynamic reserves were calculated equal to 43 × 10 6 m 3. Based on the research results, it is considered possible to pump annually an amount of 21-29 × 10 6 m 3 over the quantities of water which naturally outflow from Kourtaliotis spring, in order to satisfy the water demands in the region. The study provides a valuable guidance on predicting the groundwater reserves in aquifers with similar hydrogeological regime.

12o ΔΙΕΘΝΕΣ ΥΔΡΟΓΕΩΛΟΓΙΚΟ ΣΥΝΕΔΡΙΟ ΕΛΛΑΔΑΣ ΚΑΙ ΚΥΠΡΟΥ, ΛΕΥΚΩΣΙΑ , 2022

Περίληψη Το φαράγγι της Σαμαριάς είναι μια ιδιαίτερη περιοχή της Ελλάδας, λόγω του φυσικού περιβά... more Περίληψη
Το φαράγγι της Σαμαριάς είναι μια ιδιαίτερη περιοχή της Ελλάδας, λόγω του φυσικού περιβάλλοντος, καθώς και των γεωλογικών και βιολογικών χαρακτηριστικών. Χιλιάδες τουρίστες το επισκέπτονται ετησίως, με αποτέλεσμα πολλαπλές ανάγκες νερού και πυρόσβεσης. Ως εκ τούτου, η μελέτη και η γνώση των υδρολογικών συνθηκών του φαραγγιού της Σαμαριάς είναι ζωτικής σημασίας. Αρχικά, είναι απαραίτητος ο καθορισμός του γεωλογικού καθεστώτος της ευρύτερης περιοχής του φαραγγιού της Σαμαριάς, συμπεριλαμβανομένης της τεκμηρίωσης των τεκτονικών, λιθολογικών και στρωματογραφικών χαρακτηριστικών των γεωλογικών σχηματισμών. Ειδικότερα, η περιοχή αυτή είναι γεωλογικά δομημένη από σχηματισμούς του Άνω και του Κάτω Τεταρτογενούς, καθώς και από την Ενότητα Τρυπάλι (υπερκείμενη) και την Ομάδα Plattenkalk (υποκείμενη), που αποτελούν μέρος του μεταμορφωμένου συστήματος των Εξωτερικών Ελληνίδων. Επιπλέον, τεκμηριώνεται ο γεωλογικός σχηματισμός Γκίγκιλου, χαρακτηριστικός για την περιοχή μελέτης, καθώς θεωρείται ο πυρήνας μιας μεγαδομής. Σε αυτή την εργασία, παρουσιάζονται τρισδιάστατα γεωλογικά μοντέλα, απαραίτητα για την κατανόηση και τον προσδιορισμό του υδρογεωλογικού περιβάλλοντος. Τρεις αναλυτικές μελέτες για το φαράγγι της Σαμαριάς, που δείχνουν και συζητούν την τεκτονική και τη στρωματογραφία αυτών των σχηματισμών, αποτελούν τη βάση για την κατασκευή των αντίστοιχων γεωλογικών μοντέλων. Επιπλέον, πραγματοποιήθηκε η καταγραφή των ιδιοκτησιών των πηγών (Ιούνιος 2022), η οποία αναμένεται να συμβάλει στην εκτίμηση των υδρολογικών συνθηκών, σε συνδυασμό με τις αντίστοιχες μελλοντικές.

Water

This work represents a contribution to the protection techniques of karst aquifers against ground... more This work represents a contribution to the protection techniques of karst aquifers against groundwater pollution. The paper sets out the methodology being introduced for the protection of the karstic system that gives rise to five (5) major groups of springs and supplies fourteen (14) pumping wells near Agyia Chania (Crete, Greece). Starting from a geological and hydrogeological survey of the area, the work presents a vulnerability assessment of the karstic aquifer based on the application of three index-based methods (EPIK, PRESK and DRISTPI). The protection zones for the discharge area of the aquifer were delineated through an integrated geomorphological approach and groundwater flow modeling. At first, the risk of polluting substances migration from ground surface to groundwater was considered based on the spatial distribution of vulnerability. Following this, the vulnerability was evaluated in the saturated zone, where the attenuation mechanisms of contaminants were reducing due...

Water, 2013

In ancient Hellas, water management began in the early Minoan Era (ca. 3200-1100 BC) and was rela... more In ancient Hellas, water management began in the early Minoan Era (ca. 3200-1100 BC) and was related to the geomorphology, the geology, the topography, and the local climatic, hydrological, and socio-political conditions. Historical and archaeological evidences show that ancient Greeks had developed even qanat-related technologies since the Classical times. During democratic periods, the focus of water management was on sustainable small scale, safe, and cost effective management practices, and institutional arrangements, whereas in oligarchic periods, emphasis was on the construction of large-scale hydraulic projects, including aqueducts and/or qanats, mostly related to the public sectors. Aqueducts-like qanats are gently sloping, artificially constructed underground galleries, which bring groundwater from the mountainous area to the lowlands, where water is used, sometimes several kilometers away. It is worth noticing

Applied Sciences

The Samaria Gorge is a dominant geomorphological and geological structure on Crete Island and it ... more The Samaria Gorge is a dominant geomorphological and geological structure on Crete Island and it is one of the national parks established in Greece. Due to the complex tectonics and the stratigraphic ambiguities imprinted in the geological formations of the area, a comprehensive review of the geological models referring to the geological evolution of the area is essential in order to clarify its geomorphological evolution. In particular, the study area is geologically structured by the Gigilos formation, the Plattenkalk series and the Trypali unit. Regarding lithology, the Gigilos formation predominantly includes phyllites and slates, while the Plattenkalk series and the Trypali unit are mainly structured by metacarbonate rocks; the Plattenkalk series metacarbonate rocks include cherts, while the corresponding ones of the Trypali unit do not. Furthermore, the wider region was subjected to compressional tectonics, resulting in folding occurrences and intense faulting, accompanied by ...

Sand and kaolin compacted mixtures were tested in the laboratory to investigate the effect of app... more Sand and kaolin compacted mixtures were tested in the laboratory to investigate the effect of applied hydraulic gradient on the hydraulic conductivity measurement. Kaolin clay was added to the samples at a percentage 15, 30, 50, 70, 85 and 100% by dry weight, and hydraulic conductivity tests were performed on specimens prepared at 2% above optimum moisture content. The tests were conducted under different hydraulic gradients, using a rigid wall pressure permeameter. A definite pattern of non-Darcy behavior was recognizable in the poorly graded samples with low plasticity and fines content less than 30%. For samples with greater amount of fines and medium plasticity, Darcy behavior was observed, without a noticeable change in the flow behavior.

Advances in the Research of Aquatic Environment, 2011

Hydrogeological research in western Crete, has led to the revision of the geological map of the a... more Hydrogeological research in western Crete, has led to the revision of the geological map of the area and the creation of a new lithological map in scale of 1:25.000. According to the investigation results, Trypali Unit forms a separate hydrogeological entity in the region that is extended widely. Folding and faulting of this unit combined with the widespread fault systems determine the ground water flow in the region.

Simulation Modelling Practice and Theory, 2010

... change of the deviator stress, a technique with particular emphasis in the small strains, whe... more ... change of the deviator stress, a technique with particular emphasis in the small strains, where the stiffness modulus can be relatively high and the stressstrain response is not ... The rate of loading was constant, equal to 25 kPa/h. This rate, which was selected during the ...

Engineering Geology, 2009

This paper presents the failure process of the external waste dump of the South Field Mine, the m... more This paper presents the failure process of the external waste dump of the South Field Mine, the major open pit mine in Greece. The waste materials of the mine were deposited in three phases, forming an average inclination slope 10% and a total height of 110 m from the ground surface. The failure occurred when the third phase of the deposit was initiated. The high moisture content of the waste materials and their deposition over a spring, choking its flow, had as a result the development of high pore water pressure in clayey and marly materials in the base of the deposit. As a consequence, a large scale slope failure incident occurred. The landslide involved the mobilization of waste material in the order of 40 Mm3, while the material that moved outside the boundaries of the waste dump was in the order of 2.5 Mm3. The stability of the waste dump was investigated using the limit equilibrium analysis and different types of models.Limit equilibrium analyses were performed using different methods and considering the clay layer of small shear resistance that exists in the base of the deposit. They do not indicate activation of failure mechanism, only that there is a combination of high pore water pressure that developed in the deposit because the covering of the spring with the clayey materials of the dump.

Geotechnical and Geological Engineering