A tectonic escape structure: Erciyes pull-apart basin,Kayseri, central Anatolia,Turkey

Abstract

A large sinistral intracontinental transcurrent structure, the Central Anatolian Fault Zone (CAFZ), is located between Erzincan in the northeast and offshore of Anamur county in the southwest of Turkey. Northeastern and southwestern segments of the fault zone are linked to each other by an intervening and approximately N-S-trending transtensional structure, the Erciyes pull-apart hasin (EPB). The Krzihrmak-Erkilet and Dökmeta? segments of the CAFZ bend southwards at about 45°-50° near Kayseri and result in a releasing double bend, which has nucleated both the EPB and its main feature, the Erciyes stratovolcano complex (ESVC) since Middle Pliocene time. The EPB is a ~35-km-wide, 120-km-long, 1.2-km-deep, lazy S-shaped and actively-growing depression with the ESVC forming a high-standing central barrier between the northern and southern parts of the basin. Hence, the EPB appears as two separate basins, namely the ‘Sultansazh?i and Kayseri-Sarimsakli depressions’. However, this is not correct, because development of the EPB and ESVC has been coeval with the volcanic activity producing the ESVC continuing into prehistoric times. Development of the EPB is continuing as indicated by faulted, uplifted and terraced Pleistocene-Early Holocene palaeolake beach deposits, and historical to recent earthquakes. Accumulative throws on the eastern and western margin-bounding faults of the EPB are 1225 m and 720 m respectively and show that basin development has been asymmetrical. © 2001 Éditions scientifiques et médicales Elsevier SAS     

Attenuation modeling of recent earthquakes in Turkey

This paper deals with the derivation of a consistent set of empiricalattenuation relationships for predicting free-field horizontal components ofpeak ground acceleration (PGA) and 5 percent damped pseudoacceleration response spectra (PSA) from 47 strong ground motion recordsrecorded in Turkey. The relationships for Turkey were derived in similarform to those previously developed by Boore et al. (1997) for shallowearthquakes in western North America. The used database was compiledfor earthquakes in Turkey with moment magnitudes (M_w) = 5 thatoccurred between 1976–1999, and consisted of horizontal peak groundacceleration and 5 percent damped response spectra of accelerogramsrecorded on three different site conditions classified as rock, soil and softsoil. The empirical equations for predicting strong ground motion weretypically fit to the strong motion data set by applying nonlinear regressionanalysis according to both random horizontal components and maximumhorizontal components. Comparisons of the results show that groundmotion relations for earthquakes in one region cannot be simply modifiedfor use in engineering analyses in another region. Our results, patternedafter the Boore et al. expressions and dominated by the Kocaeli andDüzce events in 1999, appear to underestimate predictions based ontheir curves for up to about 15 km. For larger distances the reverse holds.     

Effects of compaction moisture content on the shear strength of an unsaturated clay

This paper deals with the results of an experimental study carried out on compacted clay (PL=23%) to investigate the influence of compaction water content on the shear strength of the clay. For the measurement of shear strength parameters, direct shear tests were done on samples compacted at optimum moisture content (i.e. w=24%), at the dry side of optimum (i.e. w=18%, 20% and 22%) and at the wet side of optimum (i.e. w=26% and 28%). Thermocouple psychrometers were used for suction measurements and the suction-moisture content relationship of the soil sample was obtained. The trends for suction, angle of friction and cohesion, which change below and above optimum moisture content, were analyzed. The compacted clay behaves like a granular soil on the dry side of optimum water content; and a reduction in angle of friction and an increase in cohesion are observed as the compaction water contents approach the optimum value. The angle of friction is not affected by soaking, but after soaking cohesion of the sample reduces. This revised version was published online in July 2006 with corrections to the Cover Date.     

A New Semi-supervised Classification Method Based on Mixture Model Clustering for Classification of Multispectral Data

A new method for semi-supervised classification of remotely-sensed multispectral image data is developed in this study. It consists of unsupervised-clustering for data labelling and supervised-classification of clusters in multispectral image data (MID) using spectral signatures. Mixture model clustering, based on model selection, is proposed for finding the number and determining the structures of clusters in MID. The best mixture model, for the best clustering of data, finds the number and determines the structure of clusters in MID. The number of elements in the best mixture model fits to the number of clusters in MID. The elements of the best mixture model fits to the structure of clusters in MID. Clusters in MID is supervised-classified using spectral signatures. Euclidean distance is used as the discrimination function for the supervised-classification method. The values of Euclidean distances are used as decision rule for the supervised-classification method.     

Response of pendulums to complex input ground motion

Dynamic response of most seismological instruments and many engineering structures to ground shaking can be represented via response of a pendulum (single-degree-of-freedom oscillator). In most studies, pendulum response is simplified by considering the input from uni-axial translational motion alone. Complete ground motion however, includes not only translational components but also rotations (tilt and torsion). In this paper, complete equations of motion for three following types of pendulum are described: (i) conventional (mass-on-rod), (ii) mass-on-spring type, and (iii) inverted (astatic), then their response sensitivities to each component of complex ground motion are examined. The results of this study show that a horizontal pendulum similar to an accelerometer used in strong motion measurements is practically sensitive to translational motion and tilt only, while inverted pendulum commonly utilized to idealize multi-degree-of-freedom systems is sensitive not only to translational components, but also to angular accelerations and tilt. For better understanding of the inverted pendulum's dynamic behavior under complex ground excitation, relative contribution of each component of motion on response variants is carefully isolated. The systematically applied loading protocols indicate that vertical component of motion may create time-dependent variations on pendulum's oscillation period; yet most dramatic impact on response is produced by the tilting (rocking) component.     

Estimating daily pan evaporation using adaptive neural-based fuzzy inference system

Estimation of evaporation is important for water planning, management, and hydrological practices. There are many available methods to estimate evaporation from a water surface, comprising both direct and indirect methods. All the evaporation models are based on crisp conceptions with no uncertainty element coupled into the model structure although in daily evaporation variations there are uncontrollable effects to a certain extent. The probabilistic, statistical, and stochastic approaches require large amounts of data for the modeling purposes and therefore are not practical in local evaporation studies. It is therefore necessary to adopt a better approach for evaporation modeling, which is the fuzzy sets and adaptive neural-based fuzzy inference system (ANFIS) as used in this paper. ANFIS and fuzzy sets have been evaluated for its applicability to estimate evaporation from meteorological data which is including air and water temperatures, solar radiation, and air pressure obtained from Automated GroWheather meteorological station located near Lake E?irdir and daily pan evaporation values measured by XVIII. District Directorate of State Hydraulic Works. Results of ANFIS and fuzzy logic approaches were analyzed and compared with measured daily pan evaporation values. ANFIS approach could be employed more successfully in modeling the evaporation process than fuzzy sets.     

A short note on the geo-archeological significance of the ancient Theodosius harbour (İstanbul, Turkey)

The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 ¹⁴C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.     

Thermal stresses in borehole heat exchangers

The backfilling materials of borehole heat exchangers (BHE), particularly the grout material, must provide a suitable thermal contact and ensure durability to the induced thermal stresses because of the heat loading. In this paper, the thermal stresses that occurred in BHEs because of heat injection or extraction is investigated with an analytical solution of a hollow cylinder model that is adapted for time‐dependent heat loading, the geometry of a BHE, and the thermo‐mechanical properties of surrounding ground conditions. Firstly, the hollow cylinder model is solved with the considered boundary conditions in 2D plane stress. Secondly, the temperature differences at the inner and outer circles of the cylinder are evaluated with the heat line source models for continuous and discontinuous loading to observe the impact of the heat loading schedule. The developed analytical solution for thermal stress investigation is validated with numerical models. It is demonstrated that the analytical solutions agree well with numerical results for two types of BHE configurations (co‐axial and single U‐shaped pipes). Furthermore, the calculated maximum stresses are compared with the tensile strength of grout materials obtained from Brazilian tests. It is predicted that the thermal contraction of the grout, partially constrained by the surrounding rock, generates tensile stresses that may lead to cracking in the BHE. According to the results, the stiffness of rock has a primary role on the developed tensile stresses, and the relationship between the thermal conductivity of the ground and of the grout induces a proportional impact on the magnitude of thermal stresses. Copyright © 2015 John Wiley & Sons, Ltd.