Microzonation Study of Duzce, Turkey

Duzce in Turkey was severely damaged during the November 12th, 1999 earthquake (Mw 7.2). The paper presents different surveys and studies performed after the earthquake, which resulted in the microzonation study of the city. At first we collected and analyzed all available geophysical and geological data. Then we performed a well focused geophysical and geotechnical campaign comprising a sufficient number of shallow and deep boreholes, seismic down-hole tests, array measurements of microtremors and ambient noise measurements. The synthesis of all these data resulted in the construction of the seismic geotechnical map and the geometry of the “seismic bedrock” of the city, adequate for site effect analysis. At a second stage we performed a thorough analysis of all available strong ground motion records and we carried out a detailed seismic hazard analysis, which provided the necessary input motion characteristics for the spatial analysis of the seismic ground response. Finally, we conducted a specific site effect analysis for the seismic scenario of the 1999 earthquake with a series of conventional 1D EQL analysis. The processing of the theoretical analysis results led to the estimation and the spatial distribution of the mean acceleration, velocity and displacement response spectra. As a result, Duzce was divided in seismic zones and for each one we proposed the corresponding mean design acceleration response spectra and all other characteristics of the expected ground response

Geophysical prospecting in the Krousovitis dam (N. Greece) by seismic and resistivity methods

Abstract: The use of two geophysical methods in the investigation of the geological setting in the area of a dam foundation is presented in this study. The seismic method was used in order to map the structure of the upper layers near the riverbed. VES and resistivity tomographs were also carried out. The depth to the basement was estimated by interpreting the VES curves. Interpretation of the topographic images, along with the inferred models from the seismic data, revealed the thickness of the colluvial deposits

Understanding the physics of kappa (κ): Insights from a downhole array

At high frequencies, the acceleration spectral amplitude decreases rapidly; this has been modelled with the spectral decay factor κ. Its site component, κ0, is used widely today in ground motion prediction and simulation, and numerous approaches have been proposed to compute it. In this study, we estimate κ for the EUROSEISTEST valley, a geologically complex and seismically active region with a permanent strong motion array consisting of 14 surface and 6 downhole stations. Site conditions range from soft sediments to hard rock. First, we use the classical approach to separate local and regional attenuation and measure κ0. Second, we take advantage of the existing knowledge of the geological profile and material properties to examine the correlation of κ0 with different site characterization parameters. κ0 correlates well with Vs30, as expected, indicating a strong effect from the geological structure in the upper 30 m. But it correlates equally well with the resonant frequency and depth-to-bedrock of the stations, which indicates strong effects from the entire sedimentary column, down to 400 m. Third, we use our results to improve our physical understanding of κ0. We propose a conceptual model of κ0 with Vs, comprising two new notions. On the one hand, and contrary to existing correlations, we observe that κ0 stabilizes for high Vs values. This may indicate the existence of regional values for hard rock κ0. If so, we propose that borehole measurements (almost never used up to now for κ0) may be useful in determining these values. On the other hand, we find that material damping, as expressed through travel times, may not suffice to account for the total κ0 measured at the surface. We propose that, apart from material damping, additional site attenuation may be caused by scattering from small-scale variability in the profile. If this is so, then geotechnical damping measurements may not suffice to infer the overall crustal attenuation under a site; but starting with a regional value (possibly from a borehole) and adding damping, we might define a lower bound for site-specific κ0. More precise estimates would necessitate seismological site instrumentation

Understanding single-station ground motion variability and uncertainty (sigma) – Lessons learnt from EUROSEISTEST

Accelerometric data from the well-studied valley EUROSEISTEST are used to investigate ground motion uncertainty and variability. We define a simple local ground motion prediction equation (GMPE) and investigate changes in standard deviation (σ) and its components, the between-event variability (τ) and within-event variability (φ). Improving seismological metadata significantly reduces τ (30-50%), which in turn reduces the total σ. Improving site information reduces the systematic site-to-site variability, φS2S (20-30%), in turn reducing φ, and ultimately, σ. Our values of standard deviations are lower than global values from literature, and closer to path-specific than site-specific values. However, our data have insufficient azimuthal coverage for single-path analysis. Certain stations have higher ground-motion variability, possibly due to topography, basin edge or downgoing wave effects. Sensitivity checks show that 3 recordings per event is a sufficient data selection criterion, however, one of the dataset’s advantages is the large number of recordings per station (9-90) that yields good site term estimates. We examine uncertainty components binning our data with magnitude from 0.01 to 2 s; at smaller magnitudes, τ decreases and φSS increases, possibly due to κ and source-site trade-offs Finally, we investigate the alternative approach of computing φSS using existing GMPEs instead of creating an ad hoc local GMPE. This is important where data are insufficient to create one, or when site-specific PSHA is performed. We show that global GMPEs may still capture φSS, provided that: 1. the magnitude scaling errors are accommodated by the event terms; 2. there are no distance scaling errors (use of a regionally applicable model). Site terms (φS2S) computed by different global GMPEs (using different site-proxies) vary significantly, especially for hard-rock sites. This indicates that GMPEs may be poorly constrained where they are sometimes most needed, i.e. for hard rock

Seismogenesis and earthquake triggering during the 2010–2011 Rigan (Iran) earthquake sequence

This study assesses the aftershock activity of two earthquakes that occurred on December 20, 2010 with magnitude of MN 6.5 (Global CMT Mw 6.5) and January 27, 2011 with magnitude of MN 6.0 (Global CMT Mw 6.2) in the Rigan region of southeastern Iran. This study has been done by assessing the statistical properties of the aftershock sequences associated with each of these earthquakes, namely b-value of Gutenberg–Richter relation, partitioning of radiated seismic energy, p -value of modified Omori law and the DC-value associated with the fractal dimension. The b-values of b = 0.89 ± 0.08 and b = 0.88 ± 0.08 were calculated for first main shock and second main shock sequence respectively. This suggests that this region is characterized by large differential stress; the genesis of large aftershock activity in a short time interval gives power this. Further, 2.2% of the whole energy is related with the aftershocks activity for first main shock sequence while 97.8% is associated with main shock; for second sequence, 20% of the total energy is associated with the aftershocks activity while 80% is associated with main shock. The p -values of 1.1 ± 0.12 and 1.1 ± 0.1 were calculated for first and second main shocks sequence respectively, which imply fast decay rate of aftershocks and high surface heat flux. A value of the spatial fractal dimension (Dc) equal to 2.34 ± 0.03 and 2.54 ± 0.02 for first and second main shocks sequence respectively, which reveals random spatial distribution and source in a two-dimensional plane that is being filled-up by fractures. Moreover, we then use the models to calculate the Coulomb stress change to appraise coming seismic hazard by inspecting the static Coulomb stress field due to these two main shocks for the recognition of the conceivable regions of aftershocks activity. The first main shock increased stress by more than 0.866 bars at the hypocenter of the second main shock, thus promoting the failure. In addition, the cumulative coseismic Coulomb stress changes due to the reveals that most of the aftershocks happened in the region of increased Coulomb stress

The phenomenon of rural depopulation in the Swedish landscape : Turning the trends

The objective of the study at hand is to explore the phenomenon of rural depopulation and more specifically to find out what are the methods that a region can apply in order to reverse it. Rural depopulation is a phenomenon that started taking place at the beginning of the century in Sweden. Lately the interest about urbanization and how to deal with it has increased tremendously, thus rural population decline was neglected. Some researchers though identified the problematic situation and the threats behind the phenomenon. The present paper focuses on Sweden, a country which is one of the most sparsely populated in Europe and where the phenomenon is also observed. Even though the overall population of the country keeps increasing, the number of inhabitants residing in certain peripheral municipalities decreases. The fact that Sweden experienced a significant influx of immigrants and asylum seekers during the last years doesn’t seem to have worked in an alleviating way for rural areas. As argued by previous researchers, this particular group could be a rejuvenating source for depopulated regions. Nevertheless the aforementioned group also seems to prefer relocating to the bigger centers due to better job opportunities. Starting from a research-based view the present paper will attempt to list the patterns advocating why people choose to move, and most importantly study the different initiatives that municipalities can follow in order to turn this trend that rural areas have to encounter

Συγκριτική μελέτη της κλινικής συμπεριφοράς τριών εμφρακτικών υλικών σε αποκαταστάσεις ΙΙης ομάδας νεογιλών δοντιών - Μελέτη ανάκτησης

Eισαγωγή: Τα υλικά αποκαταστάσεως παρουσιάζουν χαμηλότερα ποσοστά επιτυχίας στα νεογιλά δόντια απ’ ότι στα μόνιμα γεγονός το οποίο μπορεί να αιτιολογηθεί απ’ τις διαφορές στη μορφολογία και στο μέγεθος των νεογιλών δοντιών, στη μεγάλη αποτριβή που αυτά εμφανίζουν καθώς και στην έλλειψη συνεργασίας που παρατηρείται μερικές φορές απ’ τα παιδιά και που επηρεάζει την κλινική συμπεριφορά των υλικών. Σκοπός: Σκοπός αυτής της μελέτης ήταν η συγκριτική εργαστηριακή αξιολόγηση της συμπεριφοράς τριών εμφρακτικών υλικών (όξινων τροποποιημένων συνθέτων ρητινών, αμαλγάματος και συνθέτων ρητινών) σε αποκαταστάσεις ΙΙης ομάδας νεογιλών δοντιών μετά τη φυσιολογική τους απόπτωση. Υλικό και μέθοδος: Για τη μελέτη αυτή χρησιμοποιήθηκαν νεογιλοί γομφίοι που είχαν αποπέσει φυσιολογικά και έφεραν αποκαταστάσεις ΙΙης ομάδας κατά Black με τα εμφρακτικά υλικά: αμάλγαμα (Dispersalloy, DeTrey/Dentsply, Konstanz, GER), σύνθετη ρητίνη (Spectrum, DeTrey/Dentsply) και όξινη τροποποιημένη σύνθετη ρητίνη (Dyract, DeTrey/Dentsply). Για κάθε ένα από τα υλικά εξετάστηκαν τουλάχιστον είκοσι αποκαταστάσεις. Όλες οι αποκαταστάσεις αφορούσαν πρωτογενείς τερηδόνες που εκτείνονταν στην οδοντίνη σε ζωντανούς νεογιλούς πρώτους και δεύτερους γομφίους, όπου απαιτείτο κοιλότητα ΙΙης ομάδας κατά Black. Οι αποκαταστάσεις πραγματοποιήθηκαν από τέσσερις παιδοδοντιάτρους. Το πρωτόκολλο αποκατάστασης για κάθε είδος εμφρακτικού υλικού που χρησιμοποιήθηκε ήταν προκαθορισμένο. Στα παιδιά και τους γονείς είχε συστηθεί να διατηρούν τα δόντια με τις αποκαταστάσεις μετά την απόπτωσή τους, σε νερό βρύσης και θερμοκρασία δωματίου, σημειώνοντας την ημερομηνία απόπτωσης και να τα παραδίδουν στους παιδοδοντίατρους, το ταχύτερο δυνατό. Μετά τη συλλογή τους τα δόντια διχοτομήθηκαν κατά την εγγύς-άπω διάμετρο σε μικροτόμο σκληρών ιστών (Isomet, Buehler, Lake Bluff, Ιll, USA) και ακολούθησε η εργαστηριακή μελέτη των δοκιμίων με τις ακόλουθες μεθόδους: 1) Oπτική μικροσκοπία ανακλώμενου φωτισμού, 2) Yπολογιστική μικροτομογραφία ακτίνων-Χ (micro-CT), 3) Μικροφασματοσκο- σκοπία FTIR και μοριακή χαρτογράφηση, 4) Hλεκτρονική μικροσκοπία σάρωσης υψηλού κενού, μικροανάλυση ακτίνων-Χ και στοιχειακή χαρτογράφηση (HV-SEM/EDS). Με τις μεθόδους αυτές αξιολογήθηκαν: (α) η μορφολογική και δομική σχέση των διεπιφανειών υλικών και τοιχωμάτων κοιλοτήτων, (β) η παρουσία δευτερογενών τερηδόνων, (γ) η κατάσταση των όμορων προς τις κοιλότητες οδοντικών ιστών και (δ) οι στοιχειακές και μοριακές κατανομές που παρατηρούνται κατά τις διεπιφάνειες, απουσία ή παρουσία απασβεστιώσεων ή δευτερογενών τερηδόνων. Αποτελέσματα: Από τα αποτελέσματα της μελέτης προέκυψε ότι οι εμφράξεις με Dyract παρουσίασαν στατιστικά μεγαλύτερο ποσοστό οριακών αποκολλήσεων και ατελειών από τις εμφράξεις με Spectrum TPH. Από την άλλη πλευρά, δεν παρατηρήθηκαν στατιστικά σημαντικές διαφορές στο βαθμό επέκτασης της βλάβης στο εσωτερικό των κοιλοτήτων, στον βαθμό των σκληρών επιφανειακών εναποθέσεων και την παρουσία περισσειών κατά τα όρια μεταξύ των εμφράξεων. Κατά την ανάλυση με τον μικροτομογράφο ακτίνων–Χ αποκαλύφθηκαν αυξημένο πορώδες και ατέλειες, κυρίως στα όρια των αξονικών και αυχενικών τοιχωμάτων, στις δίεδρες και τρίεδρες γωνίες και σε στενές μασητικές αύλακες και στα δύο πολυμερή υλικά, κυρίως όμως στο Dyract. Ο μοριακός χαρακτηρισμός των διεπιφανειών αποκάλυψε μεγαλύτερου βαθμού απασβεστίωση στις βλάβες που παρατηρήθηκαν στις εμφράξεις με Dyract. Η μορφολογική μελέτη των διεπιφανειών οδοντίνης-ρητινωδών ουδετέρων στρωμάτων-ρητινωδών εμφρακτικών υλικών παρουσίασε αποκολλήσεις από την οδοντίνη και πλήρη συγκόλληση με τα εμφρακτικά υλικά. Η στοιχειακή χαρτογράφηση των διεπιφανειών των πολυμερών υλικών με τους οδοντικούς ιστούς δεν τεκμηρίωσε την ανάπτυξη μεσοφάσεων από φαινόμενα ιοντικών διαχύσεων. Όμως, στις εμφράξεις αμαλγάματος παρατηρήθηκε εκτεταμένη διάχυση Zn στη μάζα της οδοντίνης, σε μεγάλη απόσταση από τη διεπιφάνεια υλικού-οδοντίνης. Συμπεράσμα: Υπό τις συνθήκες της παρούσας μελέτης, το Dyract εμφάνισε χαμηλότερες επιδόσεις από τη σύνθετη ρητίνη SpectrumTPH και το αμάλγαμα Dispesalloy σε αποκαταστάσεις ΙΙης ομάδας σε νεογιλούς γομφίους.Introduction: Dental materials tend to reduce their success rates in primary than in permanent teeth due to the morphologic and size differences of the primary teeth, their higher extent of attrition and the lack of cooperation of young children in certain cases that can affect their clinical behavior. Αim: The purpose of this study was to evaluate comparatively the performance of three different materials (amalgam, composite resin and polyacid modified resin composites) in Class II restorations in retrieved primary molars. Materials and method: The material of this study consisted of primary molars that have been naturally exfoliated and had been treated with Class II restorations with the following materials: amalgam (Dispersalloy, DeTrey/Dentsply, Konstanz, GER), resin composite (Spectrum, DeTrey/Dentsply), and polyacid modified resin composite (Dyract, DeTrey/Dentsply). Twenty restorations of each material were examined. The restored teeth derived from two clinical studies of the Department of Pediatric Dentistry of the University of Athens. All restorations were performed by four pediatric dentists οn primary carious lesions extending to dentin, in vital first and second primary molars that required Class II cavity preparations. The restorative protocol for each type of restorative material was predetermined. Instructions were given to both parents and children to store the restored teeth after the exfoliation in tap water and in room temperature, marking the date of exfoliation, and to hand them over to the pediatric dentists as soon as possible. After the collection, teeth were sectioned at a proximal-distal direction with a hard tissue microtome and evaluated for the following: a) Morphologic and structural relationship of material-cavity wall interfaces; b) presence of secondary caries; c) dental tissue characteristics adjacent to the cavities, and d) elemental and molecular distributions along the interfaces in the presence or absence of demineralization. The study involved the following instrumentation: a) Reflected light optical microscopy; b) computerized X-ray microtomography; c) reflection FTIR microscopy and molecular mapping and d) scanning electron microscopy and X-ray microanalysis. Statistical analysis was performed with the nonparametric method Kruskal-Wallis One Way ANOVA on Ranks. The results of interfacial lesions, hard surface deposits and marginal overhangs were investigated with Dunn's Method multiple comparison test at α=0.05 significance level. The statistical analysis of the percentage reduction of calcification was conducted by One way ANOVA and Tukey’s multiple comparison test at α=0.05 significance level. Statistical analyses were performed using Sigma Stat software. Results: Optical microscopy demonstrated higher rate of marginal debonding and defects in Dyract restorations compared to Spectrum TPH. No significant differences were found in the extent of interfacial lesions, hard surface deposits and marginal overhangs. Computerized X-ray microtomography revealed bulk porosity and interfacial defects, mainly on the axial and cervical cavity walls mainly on Dyract. Spectrum TPH showed significantly lower porosity and some defects probably because of fractures in cervical enamel. FTIR microscopy showed a reduction in the mineral to matrix ratio in the dentin lesions adjacent to Dyract restorations implying greater decalcification. In the presence of resin liners, interfacial gaps were observed due to the debonding of the liners from dentin. Dispersalloy and Spectrum TPH showed lower degree of subsurface decalcification than Dyract. Elemental X-ray mapping failed to disclose development of elemental migration or diffusion gradients at the dentin-restoration interfaces. However, Dispersalloy restorations showed an extended diffusion pattern of Zn in dentin, even at a large distance from the material-dentin interface without detecting other elements of amalgam, including Ag. The mechanism of the selective permeation of Zn in such great depth is unknown, apparently through the dentine tubules, nor of the biological role. However, it is known that Zn is the strongest antimicrobial agent in terms of the elemental composition of dental materials. Clinical Significance: Marginal debonding and defects differences may imply variations in microleakage to the oral environment. Despite the similar levels of interfacial lesions, hard surface deposits and marginal overhangs, those parameters indicate different sensitivity and tooth discoloration. Bulk porosity, interfacial defects and the percentage of decalcification have revealed limited mechanical and physical properties of material and durability

The phenomenon of rural depopulation in the Swedish landscape : Turning the trends

The objective of the study at hand is to explore the phenomenon of rural depopulation and more specifically to find out what are the methods that a region can apply in order to reverse it. Rural depopulation is a phenomenon that started taking place at the beginning of the century in Sweden. Lately the interest about urbanization and how to deal with it has increased tremendously, thus rural population decline was neglected. Some researchers though identified the problematic situation and the threats behind the phenomenon. The present paper focuses on Sweden, a country which is one of the most sparsely populated in Europe and where the phenomenon is also observed. Even though the overall population of the country keeps increasing, the number of inhabitants residing in certain peripheral municipalities decreases. The fact that Sweden experienced a significant influx of immigrants and asylum seekers during the last years doesn’t seem to have worked in an alleviating way for rural areas. As argued by previous researchers, this particular group could be a rejuvenating source for depopulated regions. Nevertheless the aforementioned group also seems to prefer relocating to the bigger centers due to better job opportunities. Starting from a research-based view the present paper will attempt to list the patterns advocating why people choose to move, and most importantly study the different initiatives that municipalities can follow in order to turn this trend that rural areas have to encounter

Sustainable management of water resources of the protected lake Koronia

Nowadays, lake Koronia is the subject of many debates because this valuable water reservoir is at risk of extinction. In recent decades the lake has faced a decrease of water volume and simultaneously an increase in pollutant loads due to strong anthropogenic pressures. The aim of this thesis was the investigation of sustainable management of water resources of Lake Koronia in a holistic way, taking into consideration environmental, financial and social parameters. For this purpose, the environmental quality of the lake was evaluated through the ecotoxicological potential of water and sediment leachates samples from the lake. Farmer awareness on environmental issues and on issues related to lake Koronia as well as their intention to change practices in agriculture in order to protect the ecosystem of the lake was assessed, Finally a model of Mixed Integer Linear Programming was created, which proposes an optimal solution for the creation of a positive water balance with the lowest possible cost, taking into account the satisfaction of the water needs of the area. During the creation of the model, attempt was made to include not only financial but social and environmental factors that affect the state of the ecosystem as well. The results of this thesis shows that to ensure both quantity and quality of water resources of the protected ecosystem of Lake Koronia is necessary to design and implement sustainable management policies taking into account both financial and social prosperity as well as environmental protection measures for the region.Στις μέρες μας η λίμνη Κορώνεια αποτελεί επίκεντρο πολλών συζητήσεων, καθώς τις τελευταίες δεκαετίες παρατηρείται μία μείωση του νερού της λίμνης και ταυτόχρονα μία αύξηση των ρυπαντικών της φορτίων λόγω των έντονων ανθρωπογενών πιέσεων που δέχεται, και έτσι αυτός ο πολύτιμος υδατικός πόρος κινδυνεύει να εξαφανιστεί. Αντικείμενο της παρούσας διατριβής αποτέλεσε η αειφορική διαχείριση των υδατικών πόρων της λίμνης Κορώνειας με έναν ολιστικό τρόπο και λαμβάνοντας υπόψη περιβαλλοντικές, οικονομικές και κοινωνικές παραμέτρους. Για το σκοπό αυτό αξιολογήθηκε η περιβαλλοντική κατάσταση της λίμνης μέσω της μελέτης της οικολογικής ποιότητας υγρών έκπλυσης των νερών της λίμνης και των ιζημάτων της περιοχής, αξιολογήθηκε η ευαισθητοποίηση των αγροτών σε θέματα προστασίας περιβάλλοντος και σε θέματα που αφορούν την λίμνη Κορώνεια καθώς και η πρόθεσή τους για αλλαγή πρακτικών στη γεωργία για την προστασία του οικοσυστήματος της λίμνης και τέλος δημιουργήθηκε ένα μοντέλο Μεικτού Ακέραιου Γραμμικού Προγραμματισμού, το οποίο επιδιώκει την εύρεση της βέλτιστης λύσης για την δημιουργία ενός θετικού υδατικού ισοζυγίου με το μικρότερο δυνατό κόστος και λαμβάνοντας υπόψη την ικανοποίηση των αναγκών της περιοχής σε νερό. Κατά τη δημιουργία του μοντέλου έγινε προσπάθεια ενσωμάτωσης τόσο οικονομικών, όσο και των παραπάνω κοινωνικών και περιβαλλοντικών παραμέτρων που επηρεάζουν την κατάσταση του οικοσυστήματος. Από τα αποτελέσματα της διατριβής προκύπτει ότι για την εξασφάλιση τόσο της ποσότητας όσο και της ποιότητας των υδατικών πόρων του προστατευόμενου οικοσυστήματος της λίμνης Κορώνειας είναι αναγκαία η σχεδίαση και η εφαρμογή βιώσιμων πολιτικών διαχείρισης λαμβάνοντας υπόψη τόσο την οικονομική και κοινωνική ευημερία όσο και την περιβαλλοντική προστασία της περιοχής