No description available.

No description available.

Groundwater is one of the main sources of drinking water in Sweden. Groundwater fluctuations and the detection of flow direction is of significant environmental importance especially when there is a risk for transport of contaminations. The Swedish Nuclear Fuel and Waste Management Company (SKB) has done detailed geotechnical investigations at two potential sites for a final nuclear waste deposition. This report presents the results from groundwater modeling in quaternary deposits in one of these sites. A steady state three dimensional groundwater model was developed for a 71 km2 large area in the Laxemar-Simpevarp, 320 km south of Stockholm close to the nuclear power plant Simpevarp. For this purpose, the Groundwater Modelling System (GMS) was used. The model uses finite difference method to solve the partial differential equation for the water movement with constant density through porous medium. The main objectives were to predict the groundwater heads and the flow directions, and to study the water balance. A conceptual model approach was used by creating five heterogynous soil and rock layers. GIS (Geographic Information System) was used to create top and bottom elevation of the layers by interpolating the GIS data. The model was calibrated using observation data in groundwater monitoring wells and the optimum values for recharge and hydraulic values were found. The numerical simulation was done for two different grid sizes (511×316 m2 and 255×158 m2) referred to coarse and fine grid model respectively. Results from the multilayer model showed flow towards the sea and in the quaternary deposits but not in high elevated rocks. The water balance in the multilayer model was satisfied in both grid sizes. The 3D groundwater model GMS was successfully applied to the large Laxemar-Simpevarp region. The choice of grid size was studied and better agreements between observed and simulated groundwater heads were found in the finer grid model. Large simulation errors in some of the observation wells can indicate GMS model’s weakness in modelling thin soil layers and large variance in topography.

Rapid warming in northern latitudes will lead to permafrost thaw and subsequent carbon remobilisa­tion and release to the atmosphere. To incorporate the permafrost carbon climate feedback in globalEarth System Models, it is of importance to know the carbon stored in the circum­Arctic permafrostregion as accurate and precise as possible. Whereas soil, Yedoma and delta carbon stocks are alreadyquantified, deep carbon stocks for vast areas of the current permafrost region are still unaccountedfor. The aim of this Master thesis project is to estimate the deep carbon stock (>3m) for Quaternarydeposits outside the known reservoirs. Therefore, 363 boreholes and exposures were compiled fromthe scientific literature. 244 sites provide profile descriptions (depositional environment, depth andthickness) and another 119 sites contain data to calculate carbon densities (ground ice content, coarsefraction (>1cm and/or >2mm), bulk density and total organic carbon). Data gaps were filled usinglocal, regional and global average facies values from the compiled dataset. For spatial upscaling,key regions are defined using the permafrost zone, overburden thickness and ice content. The fielddata compiled here shows disagreements with the Circum­Arctic Map of Permafrost and Ground­Iceconditions (Brown et al. 2002), which should be updated especially in thin and ice­poor regions. Atotal C stock of 1698 ±255 PgC is estimated for 3­25m in Quaternary deposits of the circum­Arcitcpermafrost region, next to the Yedoma domain (327 ­ 466 PgC, Strauss et al. 2017) and deltas (41 ­151 PgC, Hugelius et al. 2014). About 70% of the carbon is stored within 3­10m (1200 ±238 PgC).Due to a publication bias towards thick and organic­rich sediments in the literature, C stocks calcualtedhere might be overestimated. Additional to the Yedoma domain, 309 ±99 PgC are stored in ice­richdeposits of the continuous permafrost zone, a regions especially prone to thermokarst and deep carbonremobilisation. Thermokarst, thermo­fluvial erosion along rivers and coasts as well as carbon releasethrough inland water systems presents possible release mechanisms for stored carbon. The permafrostcarbon estimate determined here doubles the known carbon reservoir in the permafrost region and em­phasises the importance for possible deep carbon release with future permafrost thawing.

Este trabalho avalia a potencialidade do emprego da sísmica de reflexão para mapear os depósitos sedimentares quaternários e o embasamento na planície costeira de Bertioga (SP). Foi feita uma aquisição CMP em uma linha perpendicular à costa e aplicado o fluxograma de processamento convencional utilizado em sísmica de reflexão. Na região estudada estão presentes o embasamento ígneo-metamórfico pré-cambriano e sedimentos de origem marinha, estuarino-lagunar/lacustre-paludial, fluvial e de encosta, de idades pleistocênicas e holocênicas. São descritos os procedimentos adotados para a escolha da área dos ensaios, para os testes de análise de ruídos, e para a aquisição CMP. Nas condições da área, a fonte de impacto tipo marreta forneceu melhores resultados em comparação com a fonte do tipo compactador de solos utilizando-se a técnica Mini-Sosie. O método mapeou dois contatos importantes com boa continuidade: o topo rochoso e uma interface que separa camadas sedimentares dentro das unidades do Quaternário. Além disso, permitiu inferir a existência de uma falha normal afetando o embasamento e sedimentos. Para a obtenção de uma seção geológica final, os resultados da sísmica de reflexão foram integrados aos resultados obtidos por outros autores do mesmo registro sísmico utilizando os métodos de tomografia por ondas P refratadas e o da análise multicanal de ondas superficiais. A sísmica de reflexão se mostrou uma potencial ferramenta para ser aplicada em ambientes costeiros, podendo trazer importantes subsídios para estudos da evolução geológica. / This work evaluates the potentiality of the seismic reflection method to mapping quaternary sedimentary deposits in the Bertioga (SP) coastal plain. A CMP acquisition was done in a perpendicular line to the coast and it was applied a conventional processing flow used in shallow reflection seismic. The geology of the study area comprises the Pre-Cambrian basement formed by igneous-metamorphic rocks, which is covered by Holocene and Pleistocene sediments of marine, estuarine-lagoonal/lacustrine-marshy, fluvial and of hillside origins. Its described the procedures adopted to choose the study area, to execute the walkaway noise tests and to acquire and analyse the CMP data. For the local geological conditions the sledge hammer gave better results compared to vibrator source used with the Mini-Sosie method. The seismic reflection method has mapped two important interfaces, the basement and the contact between two different sedimentary units, besides a geologic fault. Aiming the elaboration of a final geological section, the seismic reflection results were complemented with the results of other authors with the same data recorded, using Tomography Applied to P Refracted Waves and Multi Channel Surface Waves Analysis. The seismic reflection method shows to be a potential tool to be used in coastal environments and can contribute to the geological evolution study of the coastal plain.

Este trabalho avalia a potencialidade do emprego da sísmica de reflexão para mapear os depósitos sedimentares quaternários e o embasamento na planície costeira de Bertioga (SP). Foi feita uma aquisição CMP em uma linha perpendicular à costa e aplicado o fluxograma de processamento convencional utilizado em sísmica de reflexão. Na região estudada estão presentes o embasamento ígneo-metamórfico pré-cambriano e sedimentos de origem marinha, estuarino-lagunar/lacustre-paludial, fluvial e de encosta, de idades pleistocênicas e holocênicas. São descritos os procedimentos adotados para a escolha da área dos ensaios, para os testes de análise de ruídos, e para a aquisição CMP. Nas condições da área, a fonte de impacto tipo marreta forneceu melhores resultados em comparação com a fonte do tipo compactador de solos utilizando-se a técnica Mini-Sosie. O método mapeou dois contatos importantes com boa continuidade: o topo rochoso e uma interface que separa camadas sedimentares dentro das unidades do Quaternário. Além disso, permitiu inferir a existência de uma falha normal afetando o embasamento e sedimentos. Para a obtenção de uma seção geológica final, os resultados da sísmica de reflexão foram integrados aos resultados obtidos por outros autores do mesmo registro sísmico utilizando os métodos de tomografia por ondas P refratadas e o da análise multicanal de ondas superficiais. A sísmica de reflexão se mostrou uma potencial ferramenta para ser aplicada em ambientes costeiros, podendo trazer importantes subsídios para estudos da evolução geológica. / This work evaluates the potentiality of the seismic reflection method to mapping quaternary sedimentary deposits in the Bertioga (SP) coastal plain. A CMP acquisition was done in a perpendicular line to the coast and it was applied a conventional processing flow used in shallow reflection seismic. The geology of the study area comprises the Pre-Cambrian basement formed by igneous-metamorphic rocks, which is covered by Holocene and Pleistocene sediments of marine, estuarine-lagoonal/lacustrine-marshy, fluvial and of hillside origins. Its described the procedures adopted to choose the study area, to execute the walkaway noise tests and to acquire and analyse the CMP data. For the local geological conditions the sledge hammer gave better results compared to vibrator source used with the Mini-Sosie method. The seismic reflection method has mapped two important interfaces, the basement and the contact between two different sedimentary units, besides a geologic fault. Aiming the elaboration of a final geological section, the seismic reflection results were complemented with the results of other authors with the same data recorded, using Tomography Applied to P Refracted Waves and Multi Channel Surface Waves Analysis. The seismic reflection method shows to be a potential tool to be used in coastal environments and can contribute to the geological evolution study of the coastal plain.

Η παρούσα διατριβή έχει ως στόχο τη διερεύνηση των τεχνικογεωλογικών συνθηκών που επικρατούν στη λεκάνη Δυτικής Θεσσαλίας, με χρήση και εφαρμογή των Γεωγραφικών Συστημάτων Πληροφοριών, καθώς επίσης τον προσδιορισμό και τη στατιστική επεξεργασία των τιμών των γεωμηχανικών χαρακτηριστικών των τεταρτογενών αποθέσεων που δομούν το πεδινό της τμήμα. Στο πλαίσιο αυτό σχεδιάστηκαν ογδόντα (80) θεματικοί χάρτες με χρήση Γεωγραφικών Συστημάτων Πληροφοριών, από τους οποίους επιλέχτηκαν τελικά για παρουσίαση, εντός και εκτός κειμένου, οι πενήντα εννέα (59). Επίσης, συντάχτηκε πλήθος πινάκων, σχημάτων, χαρτογραφικών ή στατιστικών διαγραμμάτων, ενώ παράλληλα παρουσιάστηκε σειρά φωτογραφιών. Αναλυτικότερα, δίνεται κατ΄αρχήν το τεχνικογεωλογικό πλαίσιο της λεκάνης στην οποία εντάσσεται η παραπάνω έρευνα, με βάση την ανάλυση και σύνθεση στοιχείων που αναφέρονται στις γεωμορφολογικές και κλιματολογικές συνθήκες, το υδρομετεωρολογικό καθεστώς, τη σεισμικότητα και σεισμική επικινδυνότητα, τη λιθολογική σύσταση και δομή των σχηματισμών, τις υδρογεωλογικές και υδρολιθολογικές συνθήκες, καθώς και τις αποσαθρωτικές και διαβρωτικές διεργασίες των γεωλογικών σχηματισμών που δομούν την περιοχή έρευνας. Ακολούθως, παρουσιάζονται αναλυτικά οι τεχνικογεωλογικές συνθήκες που επικρατούν στη λεκάνη Δυτικής Θεσσαλίας και συντάχτηκε τεχνικογεωλογικός χάρτης σε κλίμακα 1:100.000. Στον εν λόγω χάρτη διακρίνονται είκοσι τρείς (23) τεχνικογεωλογικές ενότητες, έξι (6) για τις τεταρτογενείς αποθέσεις, δύο (2) για τους μεταλπικούς σχηματισμούς (νεογενή και μολάσσες) και δέκα πέντε (15) για τους σχηματισμούς του αλπικού υποβάθρου. Ο χάρτης αυτός συνοδεύεται από αναλυτικό Υπόμνημα. Στη συνέχεια, αναλύονται τα γεωμηχανικά χαρακτηριστικά (φυσικές ιδιότητες και μηχανικές παράμετροι) των τεταρτογενών αποθέσεων της περιοχής έρευνας, περιγράφεται η Βάση Γεωτεχνικών Δεδομένων που δημιουργήθηκε και παρατίθεται στατιστική ανάλυση των τιμών από τις παραπάνω παραμέτρους, καθώς και των αποτελεσμάτων από τις επί τόπου δοκιμές πρότυπης διείσδυσης και υδροπερατότητας. Ειδικότερα, έγινε συγκέντρωση, αξιολόγηση, τυποποίηση και καταγραφή-αρχειοθέτηση στην παραπάνω Βάση Δεδομένων των Γεωτεχνικών Πληροφοριών οι οποίες προέρχονται από 1.039 γεωτρήσεις που είχαν εκτελέσει διάφοροι φορείς του Δημόσιου και ιδιωτικού τομέα στο πεδινό τμήμα της λεκάνης Δυτικής Θεσσαλίας. Συνολικά καταχωρήθηκαν 22.463 εγγραφές σε έξι (6) Πίνακες, που στον καθένα αποθηκεύονται διαφορετικά τμήματα της γεωπληροφορίας. Επίσης, πραγματοποιήθηκε λεπτομερής ανάλυση του τεχνικoγεωλογικού πλαισίου και των σημαντικότερων παραμέτρων που υπεισέρχονται στο πρόβλημα των κατολισθήσεων. Ακολούθως, έγινε στατιστική επεξεργασία των στοιχείων της Βάσης Δεδομένων Κατολισθήσεων που δημιουργήθηκε και διερευνήθηκαν αναλυτικά οι σημαντικότεροι από τους παράγοντες που θεωρούνται υπεύθυνοι για την εκδήλωση κατολισθητικών φαινομένων και λαμβάνονται υπόψη στην εκτίμηση των επιδεκτικών προς κατολίσθηση περιοχών. Συνολικά αποτυπώθηκαν 979 θέσεις εκδήλωσης κατολισθήσεων, ενώ συντάχτηκε Χάρτης απογραφής κατολισθητικών φαινομένων και Χάρτης επιδεκτικότητας κατολισθήσεων στα όρια της λεκάνης Δυτικής Θεσσαλίας. Τέλος, καταγράφηκαν και αποτυπώθηκαν εδαφικές υποχωρήσεις που εκδηλώθηκαν σε οικισμούς (εντός ή εκτός οικιστικού ιστού) στην ευρύτερη περιοχή Φαρσάλων-Σοφάδων, ενώ διερευνήθηκαν τα πιθανά αίτια και ο μηχανισμός εκδήλωσης των φαινομένων αυτών. / The investigation of engineering-geological conditions of the Western Thessaly basin and the analysis of geomechanical characteristics of the Quaternary deposits, which occur in the flat part of the region, are examined in this thesis. In this framework, eighty (80) thematic maps have been produced using Geographic Information Systems. In addition, many tables, drawings, cartographic or statistical diagrams have been created. Moreover, a large number of photographs are also presented. The engineering-geological framework of the basin is given in detail, based on the analysis and composition of collected data, regarding, specifically, the geomorphological and hydrometeorological conditions, the seismicity and seismic hazard, the lithological characteristics and structure of the geological formations, the hydrogeological conditions, as well as the weathering and erosion processes exhibited in the geological formations that occur in the basin. Furthermore, an engineering-geological map of the Western Thessaly basin at a scale of 1:100,000 has been compiled, aiming to facilitate both urban planning and industrial development of the basin’s wider area. It is considered that this map may well contribute to the optimization of land use planning and improve the allocation and planning of civil engineering projects. The formations encountered in the basin are grouped into twenty three (23) engineering-geological unities, with regard to their geotechnical behaviour. The entire study, engaged to this thesis, was basically based on data from both in situ investigations and geotechnical information derived and evaluated from the utilisation of 1,039 existing boreholes and trial pits, in the plain part of the Western Thessaly basin. Totally 22,463 records were created and allocated in six (6) Tables. In each one of these tables different kind of geo-information were stored. The values of the above parameters were critically examined. Besides, statistical analysis was carried out on Standard Penetration and Permeability Tests result. All the geotechnical characteristics of the Quaternary deposits (physical properties and mechanical parameters) have been analyzed and a Geotechnical Database was created and presented in this thesis. Furthermore, a landslide inventory map of the Western Thessaly basin has been compiled. Many technical reports and studies, which refer to landslide occurrences, mainly obtained from the Institute of Geology and Mineral Exploration (IGME) were used to analyse and record all the landslides of the study area. A Database, using Microsoft Access, has been compiled. The connection between the Database system and Geographic Information Systems was established with the defined coordinates of the locations of existing landslide occurrences. After the necessary modifications, 979 landslide events were recorded and digitally stored. Also, a simple statistical evaluation of the available recordings was applied for the assessment of the engineering-geological data regarding the lithology and geomechanical characteristics of the encountered various geo-materials. Finally, the surface subsidence ruptures manifested in the basin’s area have been investigated.