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Objective: Caffeine is frequently used for the treatment of apnea in preterm babies. Its mechanism of action includes not only antagonism of adenosine receptors on central nervous system but also an increase in electrical activity of the diaphragm. Caffeine’s direct effect on diaphragm was investigated via electromyography, but ultrasound has not been used to show visible changes in muscles after the treatment before. Therefore, we aimed to assess the effect of caffeine on diaphragmatic function through ultrasonographic examination. Materials and Methods: It was a prospective observational study. Fifty-six participants receiving nasal continuous positive airway pressure with less than or equal to 32 weeks’ gestational age born were enrolled. Diaphragmatic thickness, amplitude of excursion, and velocity of movement were measured before and within 5 minutes after caffeine loading dose and compared to each other. The protocol was registered with ClinicalTrials.gov Identifier NCT04483492. Results: Diaphragmatic thicknesses and diaphragmatic velocity of movement did not differ after the treatment. However, amplitude of excursion of the diaphragm was found significantly higher after caffeine loading dose (8.7 mm, 10mm, respectively, P < .05). Conclusion: Diaphragm excursion increased after caffeine treatment in preterm babies, and this finding was potentially supported the direct effect of the caffeine on diaphragm. Another important finding of this study is that it reinforces the utility of ultrasonography in assessing diaphragmatic function in preterm infants. [ABSTRACT FROM AUTHOR]

On 6 February 2023, two large earthquakes (moment magnitude 7.8 and 7.6) shocked a vast area of southeastern Türkiye and northern Syria, leading to heavy casualties and economic loss. To investigate the rupture process over multiple fault segments, we performed a comprehensive analysis of local seismic and geodetic data and determined supershear ruptures on the initial branch and the Pazarcık and Erkenek segments and subshear ruptures on the Amanos segment of event 1. The bilateral rupture of event 2 also presents distinct sub- and supershear velocities. The dynamic stress of the branch fault rupture triggered the Pazarcık segment initial rupture at a point 9 kilometers west of the junction of these two faults, boosting the supershear rupture of the Pazarcık segment of the main fault. The geometry and prestress level of multiple segments controlled the rupture behaviors and influenced the ground shaking intensity. [ABSTRACT FROM AUTHOR]

On February 6th 2023 two major earthquakes struck southeast Turkey, M7.7 Kahramanmaras and M7.6 Elbistan, respectively. Unfortunately, due to the impact of these catastrophic events more than 50 000 casualties and 35 000 collapsed buildings have been reported since then. The aim of the study is to demonstrate preliminary site response analysis and assessment of re-liquefaction potential of sites which have been affected by the earthquakes - especially the cities of Iskenderun and Golbasi. Both site-specific areas have clear evidences of liquefaction and lateral spreading events which imply the focus of the presented paper. A series of geophysical MASW and microtremor tests have been performed in order to determine shear wave velocities up to depth of 30 m as well as the fundamental natural frequency of the soil deposits. Moreover, samples have been collected from sand and silt ejecta in order to evaluate some basic physical properties - grain-size curves, specific gravity and plasticity parameters. On the basis of the obtained data seismic classification of the investigated sites according to current design codes has been made and in-depth distance to relatively stiff layer has been assumed. For the sake of evaluating risk of re-liquefaction the widely-used simplified stress-based approach to triggering assessment has been adopted considering some rules of the thumb (e.g., sieve analysis and plasticity properties evaluation). Lastly, post-liquefaction reconsolidation settlement and lateral displacement have been determined in terms of future earthquakes. [ABSTRACT FROM AUTHOR]

Imaging the structure of major fault zones is essential for our understanding of crustal deformations and their implications on seismic hazards. Investigating such complex regions presents several issues, including the variation of seismic velocity due to the diversity of geological units and the cumulative damage caused by earthquakes. Conventional migration techniques are in general strongly sensitive to the available velocity model. Here we apply a passive matrix imaging approach which is robust to the mismatch between this model and the real seismic velocity distribution. This method relies on the cross‐correlation of ambient noise recorded by a geophone array. The resulting set of impulse responses form a reflection matrix that contains all the information about the subsurface. In particular, the reflected body waves can be leveraged to: (a) determine the transmission matrix between the Earth's surface and any point in the subsurface; (b) build a confocal image of the subsurface reflectivity with a transverse resolution only limited by diffraction. As a study case, we consider seismic noise (0.1–0.5 Hz) recorded by the Dense Array for Northern Anatolia that consists of 73 stations deployed for 18 months in the region of the 1999 Izmit earthquake. Passive matrix imaging reveals the scattering structure of the crust and upper mantle around the North Anatolian Fault zone over a depth range of 60 km. The results show that most of the scattering is associated with the Northern branch that passes throughout the crust and penetrates into the upper mantle. Plain Language Summary: Investigating the structure of major fault zones is important to understand the deformations of the Earth's crust and their potential impact on future earthquakes. However, the large variations of seismic velocity between different geological units drastically hampers the ability to image those areas. The North Anatolian Fault is no exception since it splits into two branches separating three major geological blocks in the region of the 1999 Izmit earthquake. To image the deep structure of this fault, seismic noise is here exploited to retrieve information on the body waves reflected by the underground heterogeneities. A three‐dimensional map of the subsurface reflectivity is then built by applying methods originally developed in optical microscopy and ultrasound for deep imaging inside complex media. The inner structure of the Earth around the North Anatolian Fault is revealed. In particular, the Northern branch is shown to exhibit a strong damage pattern and a deep penetration inside the upper mantle. Key Points: A matrix approach of passive seismology provides 3D imaging of the North Anatolian Fault, Turkey, over a depth range of 60 kmTransmission matrix between the Earth surface and the underground is extracted by means of spatio‐temporal correlations of seismic noiseTime reversal of this transmission matrix enables a sharp compensation of the seismic velocity variations in the fault area [ABSTRACT FROM AUTHOR]

The Yedisu Seismic Gap is one of the most important seismic gaps throughout the North Anatolian Fault Zone since it has not produced destructive earthquakes for a long time. To analyze the characteristics of future seismic hazards, the interrelationships between seismotectonic b-values, Coulomb stress changes, and S-wave velocity models of crust are presented in and around the Yedisu Seismic Gap located northwest of the Karlıova Triple Junction. For this purpose, the most up-to-date earthquake catalog and the focal mechanism solutions of recent earthquakes are used to image the different depth intervals. Results show that the relatively positive stresses are accumulating along the Varto Fault Zone and Kargapazarı and Yedisu Segments between 5 and 15 km depth intervals. At the same time, the lower b-values between 0.6 and 1.0 are found in the same segments. However, in the volcanic regions around the Karlıova Triple Junction, the low S-wave velocity zones may be related to high b-values, negative stress changes, and volcanic structures. The region between the Turnadağ volcano and the Varto caldera shows scattered stress and b-value changes in the upper crust. Moreover, the probability of earthquakes for Mw = 6.0, 7.0, and 7.7 in the intermediate term (10 years) is estimated as ~ 65%, ~ 17%, and ~ 5%, respectively. Recurrence of earthquakes with Mw = 6.0, 7.0, and 7.7 are calculated as ~ 10, ~ 55, and ~ 187 years, respectively. Consequently, the regions characterized by low strong b-values and positive stress loading reveal high earthquake hazard potential on the whole in the next decade. [ABSTRACT FROM AUTHOR]

The M w 7.8 earthquake in Turkey on 6 February 2023 was extraordinary for various reasons. It originated in depth of only 10 km, ruptured along a fault plane around 300 km long and the surface was covered by an extensive network of high-quality seismic instruments. The strong motions resulted in a vast number of tragic casualties and huge material losses in Turkey and Syria. However, abundant and proximate seismic observations of this event and numerous aftershocks give an opportunity to deepen the understanding of earthquake processes. In this study, we carried out an assessment of coseismic changes of seismic velocity using passive image interferometry. We used data from one strong-motion and twenty-four broad-band sensors. We observed coseismic drops of seismic velocity, which reached up to −1.79 per cent at a location directly at the ruptured East Anatolian Fault Zone. Along the M w 7.8 earthquake fault, we observe frequency dependence of the velocity changes. At frequencies above 0.5 Hz, the velocity drops seem to be higher at locations close to the ruptured faults than in the more distant areas. [ABSTRACT FROM AUTHOR]

Although there are different approaches and models to understand and interpret the structures in crustal deformations, one of them is the block modeling method. Using block modeling, one can determine plate movements, parameters such as slip rates, locking depths or Euler poles on faults. However, the accuracy of the block modeling results is related to how well the block boundaries are determined. One of the most important steps of block modeling is the detection of block boundaries and clustering can be used as a tool for this. Cluster analysis assigns data to similar groups based on similarities and differences in the data subject to clustering. In this study, Türkiye was determined as the study area. In this context, we utilized the ensemble clustering algorithm to cluster recent Global Navigation Satellite Systems (GNSS) velocity field in Türkiye and determine block boundaries. Current GNSS velocity field, which consists of 78% survey and 22% continuous type GNSS data processed together, used for clustering analysis for the first time in this study. Before clustering, we employed three different methods - Davies-Bouldin, Gap statistics, and Silhouette - to determine the optimal number (cluster number that best fit to GNSS velocity field) of clusters. Then, k-means, HAC, and spectral clustering techniques were then applied to cluster current GNSS velocities. Finally, we utilized the Meta-Clustering Algorithm (MCLA) as an ensemble clustering technique to cluster the horizontal components of the current velocity domain and present our findings. [ABSTRACT FROM AUTHOR]

This study aims to determine the datum definition for the geodetic vertical velocity field derived from temporary and continuous GNSS observations. The observations have been analysed to investigate how the effect of vertical velocity for GNSS stations depends on the reference station selection. For this purpose, a network consisting of 26 GNSS stations has been designed. The GNSS observations have been processed using Bernese GNSS software v5.2 according to the different strategies. The strategies have been generated from ten different datum definitions of one to ten continuous GNSS stations within the IGS network in the Eurasia region, which is thought to be the least affected by tectonic movements. The vertical velocities of our solution derived from four reference stations concur within 0.4 mm/yr with those of the IGS/EUREF/NGL solution. It has been determined that the vertical velocities obtained based on the four reference stations proposed within the scope of the study are equal to the vertical velocities obtained from the ten stations distributed over the European region. The usability of these outcomes has been investigated in the studies to be carried out on Turkey's west and south coasts. [ABSTRACT FROM AUTHOR]

This study includes the properties and installation stages of the microseismic network planned to be installed in a geothermal field in Turkey, which is currently producing electricity, in order to monitor the induced seismicity that will occur due to production and re-injection wells. The results of how the optimum microseismic monitoring network should be installed, the installation studies and the noise analysis of the station locations are given for this and similar geothermal fields. 7 borehole type seismometers were placed in wells drilled 65 meters deep and microseismic records of the field were obtained. The leading field equipment is SARA-SS10BHV three-component (3C) borehole type short-period velocity seismometers, and the analog data were digitized with 24-bit SL06 brand recorders. In data analysis, high frequency, low energy and small amplitude microseismic events were dealt within passive seismic records. Therefore, noise analysis is the most important step of the network installation. In the noise analysis studies, the background noise at the locations where the microseismic network stations will be deployed was determined by measurements from both on the surface and through the well, and then the results were compared with each other. According to the results, it has been determined that the noise level in the well is very low compared to the surface and this is at a suitable level for microseismic monitoring networks. [ABSTRACT FROM AUTHOR]

The Anatolian Plateau, currently experiencing rapid uplift and westward escape, records both the termination of oceanic subduction and the conversion to continental collision. The crustal response to the transition of the subduction environment from eastern to western Anatolia can be inferred by the seismic velocity and attenuation structures. With this study, we construct a broadband Lg‐wave attenuation model for the Anatolian Plateau and use it to constrain lateral crust heterogeneities linked to this transition. Crustal Lg attenuation links late Cenozoic magmatism with asthenospheric upwelling by characterizing the lithospheric thermal structure. The widely distributed strong attenuation observed in eastern Anatolia may be related to the crustal partial melting due to mantle upwelling after the delamination and subsequent break‐off of the Bitlis slab. Lithospheric dripping in central Anatolia likely facilitates the mantle flows through the window between the Cyprus and Aegean slabs, which results in the piecemeal low QLg ${Q}_{\mathit{Lg}}$ anomaly in central Anatolia. Plain Language Summary: Different parts of the Anatolian Plateau are in different evolution stages between oceanic subduction and continental collision and currently undergoing plateau uplift and tectonic escape. The regional seismic velocity and attenuation can be used to characterize crustal partial melting and lateral heterogeneity, which can further identify the underlying subduction process. In this study, we construct a high‐resolution broadband Lg‐wave attenuation model for the Anatolian Plateau. Strong Lg attenuation in Anatolia correlates well with late Cenozoic magmatism distributions and can be an indicator of high temperature or partial melting in the crust. Combined with previous studies, we suggest that the mantle upwelling induced by the delamination of the Bitlis slab is likely reworking the crust in eastern Anatolia and is the cause of widespread thermal anomalies there. The lithospheric dripping process in central Anatolia may facilitate the mantle flows through the window between the Cyprus and Aegean slabs, and results in a piecemeal low QLg ${Q}_{\mathit{Lg}}$ anomaly pattern in central Anatolia. Key Points: A high‐resolution broadband Lg‐wave attenuation model is constructed for the Anatolian PlateauWidespread strong attenuation in the eastern Anatolian crust is likely related to slab delaminationThe circular‐shaped attenuation anomaly may result from slab tearing and lithospheric dripping beneath central Anatolia [ABSTRACT FROM AUTHOR]

The Anatolia-Aegean domain represents a broad plate boundary zone, with the deformation accommodated by major faults bounding quasi-low deforming units. First-order features of this deformation were obtained in the form of a GNSS-derived velocity field. During the last decade, the accuracy of velocity solutions was improved, and the expansion of continuous networks increased spatial resolution. Nonetheless, an accurate representation of the deformation field requires interstation distances much lower than the locking depth of nearby faults, which has not yet been satisfied. The basis for creating a precise and accurate velocity field is uniform processing of the time series recorded both in the campaign and permanent GNSS stations, at once and for a single reference system. Although for Anatolia the data density has increased 6-fold since the landmark work of Reilinger et al. (2006), this crucial integration has not been made. We aim to fill this gap by analyzing the data and providing a uniform velocity solution. In this study, we processed the time series of 836 stations, of which 178 are published for the first time. With a period of up to 28 years, we present the most accurate velocity field with increased spatial and temporal resolution and homogeneity. We used the improved coverage of the velocity field to calculate strain accumulation on the North and East Anatolian Faults. Modelled slip rates vary between 20 and 26 mm/yr and 9.7 and 11 mm/yr for the North and East Anatolian faults, respectively. The data can better constrain the kinematics of continental deformation, provide accurate boundary conditions for dynamic models, and help test outstanding hypotheses about the kinematics of the Anatolia-Aegean domain. [ABSTRACT FROM AUTHOR]

The Global Positioning System (GPS), although it has existed for only 30 years, is an important source for active tectonics, resulting in estimates of plate motions very close to geologic estimates over millions of years. GPS is also used for elastic block models to calculate slip rates for a better understanding of Earth's active crustal deformation. GPS-derived velocity fields may be used as the basis for clustering analysis to create a preliminary definition of block geometry. In this study, we used published horizontal velocity fields to evaluate the effects of data dependences on determining the optimum number of clusters with algorithms. For this purpose, we used different variations of velocity fields in Turkey and tested four different algorithms that are Davies–Bouldin index, the elbow method, GAP statistics algorithm and the silhouette method. We also clustered velocity components with the k -means technique and compared the results with previous studies. [ABSTRACT FROM AUTHOR]

The present study investigates azimuthal anisotropy and its relation to the geodynamical processes beneath the back‐arc of the Hellenic subduction zone in the eastern Aegean and western Anatolia where surface tectonics is dominated by the right‐lateral strike‐slip North Anatolian Fault Zone (NAFZ) in the north and E‐W oriented normal fault systems. We obtained apparent SKS splitting parameters from 1,660 good quality and 137 null measurements extracted from 542 events recorded at 40 permanent broadband seismic stations. Overall, the station‐averaged splitting parameters indicate NNE‐SSW oriented fast directions (∼N20°E) and splitting delays around ∼1.5 s. The large splitting delays, particularly observed beneath the northern Aegean can be explained by either an enlarged mantle wedge thickness or increased strength of upper mantle anisotropy. We constrain complex anisotropy structures within two layer models from notable backazimuthal variations in individual splitting measurements observed beneath a few stations at the north located in a close proximity to the NAFZ and central‐western Anatolia. At the western end of the NAFZ, our estimated upper layer anisotropy direction (at ∼120 km) is rather parallel to the NAFZ reflecting the imprint of a lithospheric petrofabric formed by recent deformation while in central‐western Anatolia they correlate well with maximum shear directions and small splitting delays (∼0.6 s) appear to further support relatively thin lithosphere (∼90 km). An overall pattern of extension‐parallel fast directions (N10°E) within lower layer can be attributed to the slab rollback‐induced mantle flow that is highly oblique with respect to the WSW‐ward motion of the Anatolian lithosphere. Plain Language Summary: Seismological constrains on uppermost mantle structures provide essential information for better understanding of the geodynamic processes that have shaped the current deformation in complex tectonic regions. To investigate the seismic anisotropy, which is the directional dependence of seismic wave velocities, and its relation to the geodynamical processes in the upper mantle of eastern Aegean and western Anatolia, we performed splitting measurements on core‐mantle refracted shear waves recorded by 40 permanent broadband seismic stations. We overall estimate NE‐SW oriented fast polarization directions, and delay times between 0.65 and 2.2 s. The results imply that the origin of observed seismic anisotropy can be mostly explained by a combined effect of an internal deformation of the mantle lithosphere and asthenosphere. Our findings reveal the presence of two‐layer anisotropy outlining complicated structures, primarily in the upper mantle of NW Anatolia associated with the western end of North Anatolian Fault Zone. Future numerical modeling and anisotropy studies should be considered to test these results for further interpretation. Key Points: Observed seismic anisotropy can be explained by a combined effect of internal deformation of the mantle lithosphere and asthenosphereThe presence of two‐layer anisotropy is obtained beneath the upper mantle of NW AnatoliaA distinct counter‐clockwise rotation of average fast polarization directions from north to south of the Aegean region is estimated [ABSTRACT FROM AUTHOR]

In this study, maximum power point tracking (MPPT) control of a grid-connected doubly fed induction generated (DFIG)-based wind energy conversion system (WECS) at variable wind speed was designed and analyzed. The real wind speed data of the Edremit/Balıkesir region in Turkey was used as the wind speed profile. A N90/2.5 MW wind turbine model of Nordex Company was used in the study. Firstly, a conventional PI controller was applied to both rotor and grid side converters. The rotor-side converter (RSC) controls the power generated from the DFIG, whereas the grid-side converter (GSC) controls the DC bus voltage. An MPPT controller was applied to the RSC to generate reference torque at instant variable wind speeds. Thus, the system's response time, electromagnetic torque, generated power, and grid-side currents parameters were improved. In the MPPT controller, the reference torque value is produced by using the angular velocity and reference angular velocity values of the DFIG. The proposed system was modeled and simulated in Matlab/Simulink. Generated power, DC bus voltage, response time, electromagnetic torque, and grid side currents results were obtained. The results of the conventional PI controller and the results of the PI controller with MPPT were compared. The results of the proposed control were also compared with the related studies. The results showed that the proposed system is reliable, applicable, and valid for the grid-connected DFIG at variable wind speeds. [ABSTRACT FROM AUTHOR]

Abstract—Analysis of P- and S-receiver functions for 19 seismic stations on the Balkan Peninsula has been performed. Half of the stations are in Bulgaria. The crustal thickness varies from 28–30 to 50 km. The ratio of longitudinal and shear wave velocities in the upper crust reaches 2.0 in some places. In the southwest of the study area, the 410-km seismic boundary is uplifted by 10 km relative to nominal depth. The elevation may be caused by hydration and/or cooling of the mantle transition zone under the influence of the Hellenic subduction zone. A low S-wave velocity layer related to the 410-km boundary may be located atop this boundary. In the northwestern part of the study area this layer is present in spite of the absence of the 410-km boundary. A similar paradox has been previously noted in central Anatolia. Indications of a low-velocity layer are present at a depth exceeding 410 km. The simultaneous inversion of the receiver functions of the two types (P and S) and the Rayleigh wave phase velocities reveals a large (7–9%) decrease in the S-wave velocity in the upper mantle of southern Bulgaria and northern Greece. The thickness of the low-velocity layer (asthenosphere) is about 50 km. The lithosphere-asthenosphere boundary (LAB) is at depths of 40 to 60 km. In terms of tectonics, this zone is characterized as the South Balkan extension system. To the north of 43° N, the S-wave velocity in the upper mantle is usually at least 4.4 km/s and the LAB is not detected or is detected at a depth of over 80 km. The SKS analysis of azimuthal anisotropy reveals lateral zoning in the upper mantle that is correlated to velocity zoning. Probably, the mechanically weak low-velocity mantle of the South Balkan system is easily deformed, and the azimuth of the fast direction of anisotropy (20°) indicates the direction of extension. At the northern stations, the fast direction (about –30°) may be a reflection of an older process. [ABSTRACT FROM AUTHOR]

This paper reports the results of a case study of the application of the microtremor exploration method in western Turkey. We have conducted microtremor surveys at strong motion stations in Aydin and Denizli provinces to derive shallow S-wave velocity profiles. Array records of vertical microtremor motion were acquired at 12 and 15 stations in Aydin and Denizli provinces, respectively. A spatial autocorrelation analysis was applied to the records to estimate Rayleigh wave phase velocities in the frequency range of 3–30 Hz. Then, the phase velocity dispersion at each station was inverted to a one-dimensional S-wave profile down to a maximum depth of about 50 m. The soil models at 5 and 11 stations in Aydin and Denizli provinces, respectively, have a bedrock with an S-wave velocity of 400–600 m/s at depths less than 10 m. The spatial distribution of average S-wave velocities in the top 30 m of the revealed profiles shows low values in the Büyük Menderes Graben and the Denizli Basin, and high values in the surrounding hill or mountain areas. We compared our S-wave profiles with those from previous surface-wave studies. S-wave velocities in shallow parts to a depth of 5–10 m are similar in the two studies. However, S-wave velocities in deep parts are different at some of the stations. [ABSTRACT FROM AUTHOR]

The noncondensable gases in most geothermal resources include CO2 and smaller amounts of other gases. Currently, the worldwide geothermal power is a small sector within the energy industry, and CO2 emissions related to the utilisation of geothermal resources are consequently small. In some countries, however, such as Turkey and Iceland, geothermal energy production contributes significantly to their energy budget, and their CO2 emissions are relatively significant. SUCCEED is a targeted innovation and research project, which aims to investigate the reinjection of CO2 produced at geothermal power production sites and develop, test, and demonstrate at field scale innovative measurement, monitoring and verification (MMV) technologies that can be used in most CO2 geological storage projects. The project is carried out at two operating geothermal energy production sites, the Kızıldere geothermal field in Turkey and the CarbFix project site at the Hellisheiði geothermal field in Iceland. Together with a brief description of the project, this paper presents the details of the two field sites and the progress made in seismic velocity characterisation and modelling relevant to the Kızıldere geothermal field in Turkey. [ABSTRACT FROM AUTHOR]

Insulin resistance is one of the most important risk factors that accelerate atherosclerosis. The goal of this study is to investigate the relationship between the triglyceride glucose (TyG) index and functional vessel disease measured using pulse wave velocity (PWV), in a nondiabetic asymptomatic Turkish population. Nondiabetic, healthy patients (n = 1095) with no previous history of coronary heart disease were enrolled. Functional vessel disease was detected by measuring PWV. The TyG index was calculated using the following equation: log [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. The study population was divided into 2 groups based on their TyG index. The high TyG index group had higher PWV, corrected PWV, left ventricular mass index, body mass index, rates of hypertension, and was predominately male. Age, gender, blood urea nitrogen level, and TyG index were detected as independent risk factors of PWV in linear regression analysis. Triglyceride glucose index and age were also independent risk factors of the corrected PWV in logistic regression analysis. These findings show a relationship between TyG index and subclinical vessel disease, even in patients without a history of atherosclerotic cardiovascular disease or diabetes. [ABSTRACT FROM AUTHOR]

In this paper a cable-stayed bridge and a suspension bridge with closer main span lengths are considered to determine the effects of near-fault and far-fault ground motions on the structural responses of these bridges under asynchronous excitations. While the Tatara Cable-Stayed Bridge constructed in Japan is preferred as a cable-stayed bridge model, the Fatih Sultan Mehmet Bridge constructed in Turkey is considered as a suspension bridge model. While the geometric nonlinearity including P-delta effects resulting from the self weight of the suspension bridge is considered in the dynamic analysis of the suspension bridge, the nonlinearity of the cable-stayed bridge cables are taken into account with the equivalent modulus of elasticity. The results show that the traveling wave has a complicated effect on the structural responses like displacements and internal forces, and underestimates or overestimates the structural responses depending on the wave propagation velocity and the considered structural responses. It is also observed that the increment of the responses for the infinitely propagating near fault ground motions with respect to the farfault ground motions are obviously larger than the incerement obtained for the 250 m/s wave propagation velocity. [ABSTRACT FROM AUTHOR]

The significant damage observed during recent earthquakes resulting from liquefaction of shallow saturated soil deposits beneath structures has illustrated the need for further research in the area of liquefaction-induced ground movement effects. This study used the shake table facility at the University of California, San Diego to evaluate the liquefaction-induced settlement of a shallow foundation founded on top of liquefiable ground conditions. To study the seismic performance of a shallow rigid foundation, two large-scale shake table tests were conducted using different input motions with varying peak accelerations. The experimental model comprised three soil layers and included a shallow foundation seated over an unsaturated crust layer underlain by saturated loose and dense layers. The model ground was based on similar subsurface ground conditions observed in recent earthquakes in New Zealand, Japan, and Turkey. The seismic response of the model foundation and the soil was captured through intensive instrumentation. The main purpose of this study was to better understand the contributing mechanisms in liquefaction-induced settlement of buildings during strong shaking. Results from this series of tests were used to explore different liquefaction mitigation countermeasures; this study served as a baseline for two follow-on shake table tests which are not discussed in this paper. Detailed discussions of the excess pore-water pressure generation and dissipation, and its effect on the contributing mechanisms of liquefaction-induced settlement are presented, along with the application of standardized cumulative absolute velocity as an intensity measure to estimate the amount of liquefaction-induced settlement. The flow velocity calculation due to hydraulic transient gradient indicated an upward flow in the loose layer, which explains the observed sand ejecta. Measured and estimated foundation settlements were compared using simplified procedures. The observed foundation settlement generally was higher than the estimated settlement. This series of large-scale shake table tests provides a unique benchmark for calibration of numerical models, and simplified procedures to reliably estimate liquefaction-induced building settlements. Future mitigation tests can be evaluated using the results of this baseline experimental study. [ABSTRACT FROM AUTHOR]

Regression methods can be used for the prediction of parameters under the influence of environmental factors. An effective wave height prediction is important for calculating the wave potential. In the literature, the wave height prediction is generally performed by using the input parameters obtained with different physical effects, with different sensors such as water temperature, daily temperature, daily humidity, wind speed, etc. In this study, the prediction of offshore wave height has been proposed to achieve with a single parameter which is the flow velocity and contains the same physical effects of the wave unlike literature. The effect of different values on different depth of flow velocity has also been investigated by using Relief algorithm. Linear, Decision Tree, Support Vector Machine, Ensemble, and Gaussian Regression models have been studied by using different values of the specified parameters of them for two stations of Mediterranean Sea in Turkey. Various evaluation criteria (MSE, RMSE, MAE, and R_square) have also been utilized to validate the performance of the wave height prediction. The best prediction performances for B1 and B2 buoys are obtained with R_square values as 0.866 and 0.954, respectively. These results prove the achievement of the proposed. [ABSTRACT FROM AUTHOR]

In this study, shallow seismic surveys, including seismic refraction, Multichannel Analysis of Surface Waves (MASW), Refraction Microtremor (ReMi), and Microtremor measurements were conducted to estimate site characterization at 26 strong-motion stations of AFAD (Disaster and Emergency Management Presidency) in the province of Hatay, situated in one of the most seismically active regions in southern Turkey. The Horizontal to vertical spectral ratio (HVSR) technique was applied, using smoothed Fourier spectra derived from a long duration series to determine dominant frequency values at different amplification levels. Shear wave velocity up to 30 m of the ground was detected with MASW analysis. In the ReMi analysis, up to 80 m was reached with a corresponding average of 650 m/s shear wave velocity. The shear wave velocities estimated by the MASW method up to 30 m were compared with those found by the ReMi method, and they were observed to be very compatible. The province of Hatay was classified according to Vs30 based NEHRP Provisions, Eurocode-8, the Turkish Building Earthquake Regulation (TBDY-2018), and Rodriguez-Marek et al. (2001). The shear-wave velocity (Vs30), Horizontal to Vertical ratio's (H/V) peak amplitude, dominant period, and site class of each site were determined. The H/V peak amplitudes range between 1.9 and 7.6 while the predominant periods vary from 0.23 sec to 2.94sec in the study area. These results are investigated in order to explain the consistency of site classification schemes. [ABSTRACT FROM AUTHOR]

In this study, the site characteristics of 312 strong ground motion recording stations belonging to the National Strong Motion Network of Turkey (TR-KYH) operated by the Disaster and Emergency Management Authority (AFAD) were determined. Active Sourced Surface Wave Method (MASW), passive sourced linear array method (ReMi) and Microtremor methods were used in this study. The S-wave velocity-depth profile and the ground structure at different depths (down to 250 m), which can be avoided from MASW+ReMi combined inversion, are also determined at the station sites, along with the determination of the shear wave velocity to the first 30 m depth (VS30). MASW study results were classified according to Turkey Earthquake Building Regulations TDBY 2018 [1], the NHERP [2] and EUROCODE-8 [3]. According to TDBY 2018, ZA:3, ZB: 33, ZC:178, ZD:98; according to NHERP, A:3, B:37, C:173, D:99; according to EUROCODE-8, A:36, B:174, C:102 points were determined. The natural frequency and seismic amplification coefficients of the microtremor were determined and compared with those of Rodrigez-Marek et al., [4] and DiAlessandro, Carola, et al., [5]. According to Rodrigez-Marek et al.,[4] classification, A:1, B:46, C1:68, C2:34, C3:70, D1:65, D2:19, D3: 4, E2:1 point and according to DiAlessandro, Carola, et al., [5] classification, CL-I:31, CL-II:54, CL-III:55, CL-IV:82, CL-V:27, CL-VI:27, CLVII: 37 point have been identified. It is thought that the site classes and parameters of these stations obtained as a result of the study will contribute to future researches. [ABSTRACT FROM AUTHOR]

Estimating the shear wave velocity and thickness of geologic units in a sedimentary structure is important for quantifying the local site effect caused by an earthquake. Inversion of the Rayleigh wave dispersion alone is sensitive to the absolute average shear wave velocity, while the H/V spectral ratio is sensitive to velocity contrasts. The solution of these models in a joint system using conventional inversion techniques suffers from difficulties while evaluating partial derivatives, dependencies to the initial model that is sometimes difficult to estimate, and trapping at a local minimum. Herein, a joint model using the Pareto optimality technique with multiobjective particle swarm optimization was constructed as an effective global optimization method to decrease weakness and increase performance while estimating the depths and velocities. The presented approach is a multiobjective optimization method that does not require weighting, and allows evaluations of the individual objective function separately in a joint system. This study presents 2 synthetic joint system examples to account for a gradient-type and sharp velocity contrast cases, and an application from field data obtained from the Bursa Basin in Turkey. With these examples, an automated parameter search space was demonstrated to account for the abrupt velocity changes and a number of additional key points that are essential for a reasonable optimal solution. [ABSTRACT FROM AUTHOR]

Two approaches are used to develop the vertical design spectra in probabilistic seismic hazard assessment (PSHA): (i) performing PSHA for the vertical component using vertical ground motion models (GMMs), and (ii) utilizing the V/H ratio GMMs to scale the horizontal spectrum during or after the hazard calculations for the horizontal component. This study intends to develop a new framework for building a vertical ground motion logic tree that combines both vertical and V/H ratio GMMs in the PSHA analysis. For this purpose, the Turkish strong motion database (TSMD) (Akkar et al. in Journal of Seismology 14(3): 457–479, 2010) is updated with recordings from earthquakes that occurred between 2008 and 2015, including the Mw = 6.1 Elazığ and Mw = 7.2 Van earthquakes. The updated TSMD contains 2698 recordings, with the earthquake metadata, source-to-site distance metrics for the recordings, measured shear wave velocity profiles for the recording stations, and spectral accelerations for horizontal and vertical components. Four candidate V/H ratio GMMs (proposed by Gülerce and Abrahamson in Earthquake Spectra 27(4): 1023–1047, 2011; Gülerce and Akyuz in Seismological Research Letters 84(4): 678–687, 2013; Akkar et al. in Bulletin of Earthquake Engineering 12(1): 517–547, 2014a; Bozorgnia and Campbell in Earthquake Spectra, 32(2): 951–978, 2016) are selected, and the model predictions are compared with the actual data in the updated TSMD using the analysis of the residuals and data-driven techniques. Analysis results showed that the median predictions of the V/H ratio GMMs proposed by Gülerce and Akyuz (2013), Akkar et al. (2014a), and Bozorgnia and Campbell (2016) are compatible with the V/H ratios in the Turkish strong motion dataset. The findings of this study and the compatibility analysis of the vertical GMMs with the updated TSMD are combined in the accompanying manuscript (Gülerce et al. in Pure and Applied Geopyhsics, 2019, submitted) to provide the complete framework of ground motion characterization for vertical ground motion component. [ABSTRACT FROM AUTHOR]

This article investigates the stress drop variability of shallow normal-faulting earthquakes in western Anatolia through strong-motion simulations. For this purpose, source characteristics of three moderate to large magnitude events are constrained by the empirical Green's function simulation in a broadband frequency range. Recordings of ten strong-motion stations in 78-km epicentral distance range are utilized for the simulation. Estimated strong-motion generation areas (SMGAs) are 22 km2, 66 km2, and 110 km2 where rise times are 0.6 s, 0.7 s, and 0.6 s, respectively, for the 2011 Simav (Mw 5.8), 2017 Lesvos (Mw 6.3), and 2017 Bodrum-Kos (Mw 6.6) earthquakes. Those values are found to be consistent with global source-scaling relationships. One particular observation is that stress drop ratios between the mainshock and aftershock for all events are relatively large compared with those previously calculated for strike-slip events in Turkey. Stress drops of SMGAs for the Simav and Bodrum earthquakes are in the range of 25 MPa, and this value drops to 19 MPa for the Lesvos earthquake. To further investigate the stress drop variation of earthquakes in Western Anatolia, an earthquake source database (fc-Mo) offered by Yamanaka et al. (IAG-IASPEI 2017, S07-1-03, 2017) is utilized. Brune (Journal of Geophysical Research, 76:5002, 1971) stress drop values of > 360 small to moderate earthquakes (Mw 3.0–6.0) are calculated with the given corner frequency and seismic moment information assuming a constant shear wave velocity. Results indicate that the majority of the earthquakes have a stress drop value < 5 MPa. This value changes to between 5 and 57 MPa for the remaining earthquakes. These high stress drop values support the former findings stating that normal-faulting earthquakes may release higher stress than strike-slip earthquakes. This indicates that the regional stress regime in western Turkey may cause relatively larger stress release during the normal-faulting mainshocks. [ABSTRACT FROM AUTHOR]

Uzungöl settlement and Lake Uzungöl are located in the south of Çaykara, Trabzon, Eastern Black Sea region, and are an important tourist destination in Turkey, with natural beauty and rich flora. However, the settlement and the lake were formed by a historical landslide that covered the front of the Haldizen stream. Residential buildings, tourist facilities, transportation routes, and agricultural activities are located on ground that consists of the material that accumulated from the landslide. In this study, a geophysical investigation using integrated shallow seismic methods was carried out in Uzungöl settlement to provide detailed scientific imaging data on the structure of the subsurface, the physical properties of the soil and rock, the bedrock topography, and the vertical and lateral variation in the landslide deposits. For this purpose, seismic refraction and active and passive multichannel surface wave data were collected from 16 profiles in four separate zones designated according to the agricultural activity and geomorphology of the area. In addition, an electrical resistivity tomography survey of a profile was carried out to determine the reason for low-velocity anomalies such as cavities or man-made voids appearing in P-wave velocity–depth sections and underground water content. After applying basic processes including trace killing/editing, random noise filtering of the data, and amplitude balancing to all seismic data, 2D P-wave velocity–depth sections obtained by tomographic inversion, 1D S-wave velocity–depth profiles, and 2D S-wave velocity–depth sections were generated via analysis of MASW and ReMi data. P- and S-wave velocity–depth sections generally demonstrate three main lithological units in the area: the soil (Vp = 300–600 m/s, Vs = 195–350 m/s and H = 0–2.5 m), the landslide material (Vp = 600–2400 m/s, Vs = 350–680 m/s and H = 2.5–15 m), and the bedrock (Vp > 2400 m/s, Vs > 680 m/s and H ≥ 15 m). In particular, the landslide material exhibits variable thickness from profile to profile and represents the complexity of the subsurface. However, we observed that the deposit thickness increases close to the lake. It was determined that the high seismic velocities of the landslide deposits are attributable to the densely packed deposits and the primarily dry or very poor underground water, according to electrical resistivity tomography results. Moreover, the top of the bedrock is characterized by soft rock, and the deeper part of the bedrock is harder and more compact. We believe that this information will be a useful contribution to geotechnical project development and risk mitigation in the Uzungöl area. [ABSTRACT FROM AUTHOR]

This study aims to reveal upper-crustal velocity structure of Inner part of Izmir Gulf by using ambient noise tomography. One-year noise data have been used from 17 stations belong to IzmirNET. Rayleigh wave group velocities which present good signal/noise ratio have been obtained from dispersion curves by using multiple filter technique. Results have been mapped for 2, 4 and 6 s period intervals. Then, shear wave velocities have been obtained from the inversion of group velocity by using local dispersion curves belongs to same periods. Low velocity areas representing alluvial deposits beneath Inner part of Izmir Gulf, have been precisely observed down to 3 km on group and shear wave maps. Added to this, it is also detected not only the existence of low velocities but also high values in the depth slices of inner part of the Gulf. This method may provide precise and high resolution images of crustal structure and upper mantle by using ambient noise tomography without seismic events. It can be applied in the future to the Aegean Region, Turkey or neighbouring countries by using broad-band data set. [ABSTRACT FROM AUTHOR]

Turkey's poultry industry has experienced significant growth in recent years, resulting in the construction of many new production facilities. It is important to maintain optimum environmental conditions for a profitable production. In this study, temperature, relative humidity and air velocity distribution inside a broiler house were analysed. Computational Fluid Dynamics (CFD) simulations (numerical method) and direct measurements (experimental method) were used to determine the appropriate indoor environmental conditions. Simulated values were validated by comparison with the measured values using the normalised mean square error (NMSE). The measured and predicted parameters of temperature, relative humidity and air velocity at birds' height, human height, and roof height upon comparison gave average NMSE values of 0.139, 0.181 and 0.090, respectively. The results showed a good agreement between simulated and measured values as obtained NMSE values were less than 0.25. In conclusion, CFD simulation can be used as an alternative method for the analysis of poultry house indoor environment. A better understanding of indoor environment conditions in poultry house provides useful information for manufacturers and end users for better management decisions. [ABSTRACT FROM AUTHOR]

In this study, density, porosity, void ratio, and ultrasonic P- and S-wave first arrival times were measured on limestone, sandstone, and siltstone samples obtained by using mechanical soundings in the city of Zonguldak. Turkey. Fracture and fissure indexes of rocks were calculated from ultrasonic P- (Vp) and S-wave (Vs) velocities. Multi-parameter relationships occurred between ultrasonic velocities with seismic fracture and fissure indexes and physical and mechanical properties of the rocks. Root mean squared error (RMSE = 0.5–0.8%) values correlated between measured densities and densities calculated from Vp and Vs. The correlation coefficients of experimental relations between densities, void ratio, and porosity with seismic velocities that were obtained ranged from 78, 86, 67, and 84%, respectively. Consequently, natural, water-saturated and grain densities, porosity, and void ratio values were determined from new multi-parameter relationships obtained from the combined use of Vp and Vs. In addition, the results of this study suggest that the rock quality may wrongly be determined using the only Vp, whereas it can be obtained more accurately by using Vp and Vs together. The reason for this is that the P wave spreads in solid, liquid, and gas media, while the S-wave spreads only in solid media. Therefore, S-waves will not be altered by fracture filling (gas or liquid), while P-waves are affected by fracture filling. In the present study, the use of Vp and Vs together in relationships was more useful in determining the strength and hydraulic properties of rock mass that the use of either Vp or Vs alone. Also, Rock Quality Designation (RQD) and Rock Mass Rating (RMR) values can be correctly calculated from the combined use of Vp and Vs. As a result, interpretation of crack fill and classification of the rocks can be quickly performed using seismic velocities. [ABSTRACT FROM AUTHOR]

Global positioning system (GPS) velocities have long and widely been used on various scales in revealing the deformations of the continental lithosphere. We present a homogeneous geodetic velocity field with high precision derived from ~ 10-year-long permanent GPS observations throughout Turkey. Without any apriori information or assumption, the cluster analysis might be applied upon the velocity fields for inspection, before going further in the analyses used prevalently in tectonic studies. We first "hard clustered" the velocities using k-means, hierarchical agglomerative clustering and Gaussian mixture models and examined how the cluster assignments change by tuning the algorithm-specific parameters. The Eurasian and the Arabian blocks which are separated from the Anatolian block with the strike-slip North and East Anatolian faults have been detected immediately. The Anatolian block itself has been divided into three blocks where the cluster assignments of the velocities at the transition zones might differ according to the chosen hard clustering algorithm. We then applied soft clustering using an appropriate Gaussian mixture model fit and created a probability map exhibiting the credibility of the cluster assignments. The detection capability of the cluster analysis has been demonstrated by comparison to various previously published block models of western Turkey. Cluster analysis detected the most pronounced blocks in western Turkey successfully, especially when the initially chosen number of clusters is not too large. The probability map of soft clustering can be used to modify the block boundaries together with the external validation. [ABSTRACT FROM AUTHOR]

Major strike-slip fault systems on Earth, like the North Anatolian Fault (NAF), play an important role in accommodating plate motion, but surprisingly little is known about how such structures evolve through space and time. Along the central sector of the NAF in the Central Pontides, transpression and crustal thickening along the northward restraining bend of the fault are thought to have generated rock-uplift rates of 0.2–0.3 km/Myr since at least 400 ka based on Quaternary marine and river terraces, while data from low-temperature thermochronology suggest that an enhanced exhumation phase occurred within the last 11 Myr. However, the precise onset of this faster uplift phase, which likely reflects deformation associated with the development of the central sector of the NAF, is poorly constrained. Here we define the spatiotemporal pattern of rock-uplift rates within the Central Pontides over the last ∼10 Myr by performing linear inversions of 19 river profiles that drain the northern margin of the Central Pontides, from the Sinop Range to the Black Sea. We use 21 new 10Be-derived basin-average denudation rates to calibrate an erodibility parameter, which we use to convert our χ -transformed river profiles into rock-uplift histories. Our results document an increase in rock-uplift rates after 10 Ma, with peak rates of ∼0.15–0.25 km/Myr occurring between 4 and 2 Ma. Moreover, the spatiotemporal pattern of uplift suggests that faster rock uplift started in the eastern part of the Sinop Range and migrated westward over a period of ca. 2 to 2.5 Myr, which we relate to the westward propagation of the NAF through this sector at a rate of 74 ± 13 km/Myr. In the context of previously published constraints on the westward propagation of the NAF starting in eastern Turkey at ∼12 Ma, our results suggest differences in fault-propagation rates that coincide with differences in the orientation of the NAF relative to plate-convergence velocity vectors. Fault segments with higher obliquity appear to have propagated at rates up to 2-fold slower than those oriented more parallel to the plate-convergence vector. • Rock-uplift history of Central Pontides from river linear inversions. • The uplift event after 10 Ma dates the arrival of the North Anatolian Fault (NAF). • The uplift migration provides the propagation rate of the NAF central segment. • New insights about the propagation history of all the NAF segments. • Linkage between NAF propagation rates and plate convergence directions. [ABSTRACT FROM AUTHOR]

The goal of this study is to establish a workflow for the re-interpretation of almost depleted fields targeting the long-term sustainable oil production; in particular, for the oil fields in Turkey and the neighboring Middle Eastern countries located on the fold and thrust belts of the Zagros Mountains. It also fills some of the gaps in our understanding of the northern part of the Arabian Platform by describing the seismic characteristics of the Cretaceous reservoirs that were deposited during the Aptian to Turonian. The Katin-Barbes oil field (KBOF) in SE-Turkey was used as a case study. In this area, 3D seismic data were used for structural interpretation and re-modeling of Cretaceous carbonates sedimented in the complex tectonic region. The well logs from 55 wells in the field were used to create a compilation of formation tops and were used as reference points for two separate sets of 3-D seismic data, acquired in 1991 and 2017. The quality of seismic data was improved with interpretation filters. The structural model was obtained by using various qualifiers from the seismic cubes and seismic facies changes were identified by analyzing a number of seismic attributes. Therefore, seismic data and velocities from the borehole measurements were combined to form a velocity model in building a structural model. Seismic attributes and well logs were used to create a porosity model. Consequently, top and base of two reservoir units; the Derdere and Sabunsuyu Formations have been clarified and re-defined, and potential new well locations were identified. Depending on the results of this investigation, 9 new wells were drilled in the potential areas in the KBOF, recently. Except the last one drilled on the NE boundary of the northern block, all wells have been completed as the "oil producing wells" and top of the reservoir units were encountered at almost the same depths in our depth model. Therefore, results and proposed methods in this research are confirmed by the real, borehole data. This research will be an examplary study for the re-evaluation of older and/or almost depleted oil fields, either in Turkey or in the other Middle Eastern countries. • This study indicates the seismic characteristics of Aptian to Turonian units on the N of Arabian Platform. • Some innovative steps were indicated in an old HC field after new seismic data. • New drillable locations were determined in this old oil field, KBOF. • The goal of this preliminary study is to establish a framework for long-term oil production in the almost depleted fields. [ABSTRACT FROM AUTHOR]

This paper presents new models of the seismic velocity structure of Eastern Anatolia, Turkey. We applied a local earthquake tomography method to arrival time data produced by local and regional events in Eastern Anatolia to understand the three-dimensional seismic velocity and Vp/Vs models and their correlation with the geological evolution and tectonic processes in the study area. The data are obtained from 78 broadband seismic stations, owned by the Earthquake Department of the Disaster and Emergency Management Presidency, for the period between 2008 and 2017. Seven depth cross sections are taken along various segments of the East Anatolian Fault Zone. Travel times of 53,099 phase readings (29,122 P-phase and 23,977 S-phase picks) from 4249 high-quality earthquake recordings are analysed to develop 3-D Vp (lithological) and Vp/Vs (petrological) models of the study area. The resulting P-wave velocities describe intrusive magmatic bodies, sediment thickness and the structure of the basin. The Vp/Vs structures aid to limit the position of the faults, areas of weakness, and gas- or liquid-saturated units with regions of high pore pressure. Four main seismic crustal layers down to 40 km are determined. The upper crust (0–8 km) has Vp ≤ 4.6 km/s, whereas in the middle crust (~ 9–20 km) a Vp perturbation between 4.6 and 5.8 km/s is observed. In the lower crust (~ 20–35 km), Vp changes from 5.9 to 7.3 km/s and in the upper mantle layer (below 36 km), Vp exceeds 7.4 km/s. In all cases, seismic velocities are well-resolved in the first 40 km. Tomograms are compatible with the geological characteristics of the region. Dominant high P-velocity values are observed beneath the collision zone. Conrad discontinuity is detectable at 20 km depth, while Moho depth is observed to vary between 30 and 40 km in the study area. [ABSTRACT FROM AUTHOR]

We use observations of surface waves in the ambient noise field recorded at a dense seismic array to image the North Anatolian Fault zone (NAFZ) in the region of the 1999 magnitude 7.6 Izmit earthquake in western Turkey. The NAFZ is a major strike-slip fault system extending ∼1200 km across northern Turkey that poses a high level of seismic hazard, particularly to the city of Istanbul. We obtain maps of phase velocity variation using surface wave tomography applied to Rayleigh and Love waves and construct high-resolution images of S-wave velocity in the upper 10 km of a 70 × 30 km region around Lake Sapanca. We observe low S-wave velocities (<2.5 km s -1) associated with the Adapazari and Pamukova sedimentary basins, as well as the northern branch of the NAFZ. In the Armutlu Block, between the two major branches of the NAFZ, we image higher velocities (>3.2 km s -1) associated with a shallow crystalline basement. We measure azimuthal anisotropy in our phase velocity observations, with the fast direction seeming to align with the strike of the fault at periods shorter than 4 s. At longer periods up to 10 s, the fast direction aligns with the direction of maximum extension for the region (∼45 ∘). The signatures of both the northern and southern branches of the NAFZ are clearly associated with strong gradients in seismic velocity that also denote the boundaries of major tectonic units. Our results support the conclusion that the development of the NAFZ has exploited this pre-existing contrast in physical properties. [ABSTRACT FROM AUTHOR]

The geocentric datum of Turkish CORS Network (TUSAGA-Aktif) is a semi-kinematic datum realized with respect to the International Terrestrial Reference Frame (ITRF 96) at the reference epoch of 1 January 2005 (2005.00). This realization was maintained by ITRF no net rotation (NNR) velocities of CORS stations. Up-to-date ITRF NNR velocities were determined by General Command of Mapping in Turkey using 7 years of CORS stations data from 2008 to 2015. In accordance with Turkish surveying regulation, there are two types of coordinate computation of the control points performed with Global Navigation Satellite System relative positioning technique based on the datum. Coordinates of the first-order and the second-order control points are computed in semi-kinematic datum, whereas the third-order control points are computed in static datum. Generally, CORS stations of TUSAGA-Aktif are used as fiducial stations for coordinate computation of these control points. In this study, baseline deformation effect of static datum on the three-dimensional position of the points are investigated. 20 CORS stations within TUSAGA-Aktif were chosen to simulate the rover and the fiducial stations. The results show that relative displacement from the reference epoch (2005.00) between the rover-fiducial stations at the measurement time and the positioning error of the rover station are in a good agreement. The differences are in the order of mm to cm level. The results also show that when more than one fiducial station used in static datum processing, mean relative displacement between the rover-fiducial stations at the measurement time and the positioning error of the rover are also in a good agreement. The results emphasized that, velocities of the fiducial stations should be known by the users for conducting static datum processing with minimum baseline deformation as much as possible. [ABSTRACT FROM AUTHOR]

• The first 3-D Neogene velocity-depth model of the Gulf of İzmir obtained up to 1.7 km depth. • The Miocene acoustic basement displays asymmetrical upper surface morphology with ridges and basins. • Four Plio-Quaternary stratigraphic units fill the basement with varying thicknesses. • Lateral and vertical velocity anomalies documented within the Plio-Quaternary deposits. • The low-velocity zones are interrupted laterally by the high-velocity zones corresponding to squeezed sediments of the Karaburun Fault Zone. • The fault-controlled velocity anomalies suggest gas/fluid and heat transfer along faults from a deeper source. There are basins with proven hydrocarbon and geothermal sources across western Anatolia. Only a few moderate-scale tomography studies investigate their velocity structure and stratigraphical architecture. We present the first 3-D Neogene velocity-depth model of the Gulf of İzmir down to ∼1.7 km. The aim is displaying a better portrait of the 3-D stratigraphical architecture, velocity structure of the Gulf of İzmir, and constitute a solid foundation for future studies. We provide the first 3-D view of the complex Late-Miocene basement topography representing an unconformity surface. It consists of basins and ridges separating the Miocene basement (SSU3) and overlying Plio-Quaternary deposits (SSU2 and SSU1). Four N S oriented volcanic ridges accommodate offshore Uzun Island, Karaburun, and Foça. They border a basin with a thickness of ∼720 m in the mid-central and a deeper one with ∼1400 m in the northernmost sector of the gulf. The 3-D P-wave traveltime tomography results indicate prominent lateral and vertical velocity variations at different depths (∼300–800 m). The low-velocity zones (1600 ≤ Vp ≤ 1850 m/s) are interrupted laterally by the high-velocity zones (2150 ≤ Vp ≤ 2350 m/s) that corresponds to the squeezed sediments within Plio-Quaternary basins deformed by the N S trending strike-slip faults of Karaburun Fault Zone. The same faults also deform the volcanic basement highs identified by the high velocities (>2600 m/s). The thick depocenter with low-velocity anomalies in the outer gulf suggests the gas/fluid containing sediments. Their controlling faults are likely responsible for the circulation of gas/fluid and heat transfer from a deeper source making the region target for exploration activities. [ABSTRACT FROM AUTHOR]

• Focus on reflection amplitudes for studying the effect of a CO 2 -saturated fracture. • S-wave velocity is more sensitive to changes in pore pressure than P -wave velocity. • Stress-dependency of the P-wave velocity increases with temperature. • Temperature-dependency of the P-wave velocity increases with reducing stress. As part of a seismic monitoring project in a geothermal field, where the feasibility of re-injection and storage of produced CO 2 is being investigated, a P- and S-wave seismic velocity characterisation study was carried out. The effect of axial and radial (up to 42 MPa) stress, pore pressure (up to 17 MPa), pore fluid (100% brine or supercritical CO 2) and temperature (21–100 °C) on seismic properties were studied in the laboratory for the two main reservoir formations at the Kızıldere geothermal reservoir. Each (un)confined compressive strength test performed revealed a similar trend: rapidly increasing velocity at low stresses followed by a more moderate increase at higher stresses. The data implied that the stress-dependency of the velocity increased with temperature. Increasing temperatures resulted in decreasing P-wave velocities due to mineral thermal expansion. This temperature-dependency increased with reducing stress levels. The S-wave velocity seems to be more sensitive to changes in pore pressure than the P-wave velocity. On the other hand, the S-wave velocity is less affected by an increasing axial stress compared to the P-wave velocity. By performing multiple nonlinear regression on the velocity dataset, related to a brine-saturated fractured marble, second-degree polynomial trends were found for the P- and S-wave velocity, as a function of temperature, axial stress, and pore pressure, that can potentially be used for predicting velocities at Kızıldere, or other similar, geothermal site(s). For distinguishing between a 100% brine-saturated versus a fully supercritical CO 2 -saturated fracture, the arrival times of the first arrivals were too close to each other to allow their utilization. The fracture aperture was too small compared to the wavelength of the source signal. However, differences in P- and S-wave amplitudes of the first arrivals were seen, where the supercritical CO 2 -saturated crack revealed consistently lower peak and trough amplitudes compared to the brine-saturated scenario. [ABSTRACT FROM AUTHOR]

Convergence of the Africa, Arabia, and Eurasia plates and the westward escape of Anatolia have resulted in an evolving plate boundary zone in the Eastern Mediterranean. The current location and nature of the plate boundary between the Anatolian and the African plate is difficult to trace due to the scattered crustal earthquakes and the absence of deep ones. We examine various types and locations for the plate boundary as constrained by seismicity, seismic reflection studies, tomographic studies, and geodetic measurements and we use a spherical plane stress finite element model to test these possibilities. In our regional model, we impose the convergence of Africa, Arabia, and stable Eurasia by applying GPS-derived velocities in the far-field, as well as the roll-back of the Hellenic trench to solve for regional deformation. Model velocity and stress fields are compared with GPS-derived velocities and stress directions from focal mechanism solutions. We find that the plate boundary via the Pliny and Strabo trenches, the Anaximander Mountains, the Eratosthenes Seamount collisional segment, and the Latakia-Larnaka ridges gives the best fit to the data. The Anaximander Mountains plate boundary has both down-dip and strike-slip motions, and the Latakia segment is pure strike-slip. The Cyprus subduction contact is 42% locked. From a combined analysis of indicators for long-term deformation (predominantly slip-rates on major faults) and model results we infer that this southern plate boundary configuration may have existed since the Late Pliocene. [ABSTRACT FROM AUTHOR]

In this study, seismic assessment of one story precast industrial buildings that constitute majority of industrial facilities in Turkey was investigated by using probabilistic approach. For this purpose, 98 one story precast industrial buildings that represent general structural aspects of precast industrial building stock of Turkey were used. Strength and deformation capacities of buildings were determined by inelastic methods and seismic demands were calculated by nonlinear time history analyses. In order to represent low, moderate and high intensity earthquake levels, more than 300 ground motion records were used. Fragility curves of precast buildings were then constructed by comparing the displacement capacities and seismic demands. Peak ground velocity was used as ground motion parameter to construct analytical fragility curves. Assessment of inventory buildings was performed by considering the effect of lateral strength ratio, stiffness and ductility parameters. Observations have shown that probabilities of lower damage levels (slight and moderate) are almost similar and they are independent from structural parameters considered. It was also observed that ductility and lateral strength ratios (V/W) have significant effect on seismic fragilities of precast industrial buildings at higher damage levels. Based on the observations, building stock was classified in three groups. Results have shown that strength and ductility based classification of existing precast industrial buildings is quite effective and it can be used as an important tool for the seismic assessment studies of one story precast industrial buildings. [ABSTRACT FROM AUTHOR]

In this study, two-dimensional electrical resistivity tomography (ERT) and one-dimensional multi-channel surface waves analysis (MASW) methods conducted on the surface were used to examine the location of a creek drainage tunnel constructed for the campus road and its relationship with the surrounding geological units in the Kocaeli University campus site results are presented. As it is known, geophysical studies conducted from the surface are generally applied in terms of feasibility and to determine the geological problems in the route of tunnels before the tunnel construction. Geophysical studies revealing the tunnel and associated underground characteristics in a completed tunnel are very limited. Therefore, this study aims to describe the general character of the tunnel and its surroundings in the subsurface, with measurements made by using surface geophysical methods (ERT and MASW) over the tunnel. In the ERT studies, four different arrays were examined to resolve this problem. These are, respectively; Wenner-alpha, −beta, −gamma and Schlumberger. On the tunnel problem here, a possible model similar to the geological structure dominated by the marl layers in the region was synthetically designed with these arrays. In this study, the effectiveness of all these arrays against the problem was tested. Then, by evaluating the data collected from the field, the appropriate array testing was examined for the real problem. In the context of these studies, the results of the MASW studies conducted between 24 and 46 m of the ERT line were compared with the ERT data to reveal the geological phenomena in the tunnel and its vicinity. The resistivity values (ρ) in the 2D electrical resistivity models obtained from ERT have values of ρ > 80 Ωm in the tunnel section and ρ < 55 Ωm in the materials surrounding the tunnel. The medium-high resistivity values characterize the earthfill layer. In MASW studies, it was revealed that shear wave velocity (Vs) values in the tunnel were lower (<250 m/s) and higher (250 and 500 m/s) in the materials surrounding the tunnel. Deep below the tunnel and in the northeastern part of the field, the ground has relatively higher shear wave velocities (Vs > 400 m/s). Because of the comparison of ERT and MASW results, it was revealed that both methods showed good agreement in terms of tunnel depth and size. While the different sequences used in the ERT study generally provided successful results in identifying the tunnel, different model results were revealed in the surrounding earthfill, weathered and intact marl layers. The MASW results, on the other hand, gave more successful results than expected in determining the location of the tunnel. Because of the comparison of both methods, it has been shown that the use of the ERT and MASW methods together can provide more effective results in examining the location of buried tunnels and their relationship with the surrounding geological units. • Application of geophysical methods on the tunnel with known overall properties. • Combined application of electrical resistivity tomography and multichannel analysis of surface waves methods. • Determining a tunnel buried at a depth close to the surface in terms of location, shape, shear velocity and resistivity. • Application on both synthetic and field data set. [ABSTRACT FROM AUTHOR]

Turkey, located at an area of active seismic zone, has vast records of many earthquakes. The liquefaction phenomena have become crucial issue in Turkey since Erzincan Earthquake took place in 1992. Soil liquefaction was observed widely during Marmara and Duzce Earthquakes in 1999 as well. In this study, the liquefaction potential of vicinity of Fethiye village in Turkey was investigated via results of blow counts (N) of Standard Penetration Test (SPT) and velocity measurements of seismic refraction tests at 40 different locations in the investigated area under an earthquake magnitude (Mw) of 7.0. Liquefaction severity maps were prepared according to liquefaction severity index that is function of the input parameters such as SPT-N values, ground water level, fines content and shear wave velocity. The results of study reveal that the investigated area has either no potential liquefiable or low susceptibility liquefiable zones under Mw = 7.0. [ABSTRACT FROM AUTHOR]

Vertical movements of the solid Earth surface reflect crustal deformation and deep mantle related phenomena. For Holocene times, coastlines displaced from the present mean sea-level are often used together with past relative sea-level (RSL) prediction models to decipher the vertical deformational field. Along the coastline from southwest Turkey eastward to Israel and Cyprus, field data that constrain Holocene vertical movements are already published, leaving a gap only along the Mediterranean coast of the Central Anatolian Plateau (CAP). Based on new field observations between Alanya and Adana (Mersin, southern Turkey), together with AMS 14C dating, we fill that gap, allowing for the construction of a continuous overview of Holocene vertical differential movements along the Eastern Mediterranean coast. We apply the most recent Glacial Isostatic Adjustment (GIA) models to correct for the glacio-hydro isostatic component of the RSL. Different solutions from the ICE-6G(VM5a) and ICE-7G(VM7) models (developed by W.R. Peltier and co-workers at the Toronto University), and a GIA model developed by K. Lambeck and collaborators at the Australian National University, have been applied to 200 middle-to-late Holocene RSL markers. Starting from southwest Turkey, we find subsidence between −0.9 mm/yr and − 2.3 mm/yr, corroborating estimates from previous studies. Velocities from the new markers along the CAP Mediterranean coast are positive, ranging between 0.9 and 1.5 mm/yr. These two first blocks are separated by a sharp velocity jump, occurring along the Isparta Angle Fault System one. Such high vertical velocities for the CAP southern margin were predicted by recently published papers that report a rapid uplift phase that peaked during themiddle to late Pleistocene. Moving to the east, velocities are also positive, from 0.2 to 0.6 mm/yr along the coast between the Hatay Gulf and southern Lebanon. The highly variable velocity along the Lebanese sector is likely due to co-seismic deformation along the Lebanese Restraining Bend (LRB) faults. To the south, in contrast, the Israeli coast shows stability, according to some unique archaeological RSL markers named piscinae, whereas other markers indicate slow subsidence (−0.2 mm/yr on average). Hence, another velocity jump of at least 0.5 mm/yr is recognizable between Israel and Lebanon. This jump is probably associated with mapped, active tectonic structures. In Northern Cyprus, the only Holocene sea-level marker confirms the near zero vertical velocity values already obtained for the MIS 5e marine terrace. Therefore, a vertical velocity jump occurs between stable Northern Cyprus and the uplifting CAP southern margin, although they occur on the same overriding plate of the Eastern Mediterranean subduction system. High-angle normal faults at the northern margin of the Adana-Cilicia Basin could explain these strongly distinct late Holocene vertical velocity fields. These results depict a complex framework of independently moving crustal blocks, with kinematic separation along well-known regional fault zones. The drivers of the block movements could be related either to regional tectonics, as it is probably the case for the LRB coast, or to mantle dynamics, such as for the uplifting Turkish sector, where deeper processes should be considered. [ABSTRACT FROM AUTHOR]

Multi-frequency P- and S- wave attenuation tomography models of Lake Van area (East Anatolia) have been obtained by estimating coda-normalized wave spectra of 3027 local earthquakes (2.0 < Mw < 7.1). The 6998 waveforms sampled from surface to a depth of 25 km, and were recorded from 2004 to 2020 at seven broadband, three-component digital seismic stations operated by Kandilli Observatory and Earthquake Research Institute (KOERI). We adopted a two-point ray-bending method to trace rays in a 3-D velocity model. We applied the coda normalization (CN) method to P - and S -wave data sets. We inverted the spectral data with a multiple resolution seismic attenuation (MuRAT) approach to obtain final tomographic models. On average, high (low) attenuation corresponds to low (high) velocity anomalies. The P- and S- wave attenuation contrasts delimit four well-known geological zones. High frequency-short wavelength attenuation contrasts constrain the 5-km-deep zone of interaction between magma and sediments within the Lake Van basin. Low frequency-long wavelength attenuation anomalies mark the central section of Lake Van between depths of 10 km and 20 km. This zone coincides with a rigid stable shear zone overlying a possible weak-ductile lower crust, interpreted as a detachment. Both low (5–15 km depth) and high attenuation (>20 km) anomalies mark the area of maximum seismic energy release during the Van event. Their contrast highlights the maximum seismogenetic depth above weak-warm, unstable materials. High attenuation in the SE-part of the Lake Van area coincides with a large hydrothermal and/or magmatic folding-overthrusting, interpreted as a suture-metamorphic complex between depths of 10–15 km. Other minor high-attenuation zones deeper than 5 km focus on complex shear zones in the area damaged by the Van event. The paired attenuation structure of the Lake Van area appears linked to multiple tectonic processes of crust-magma interaction better constrains subsurface segmentation structures and differential deformation types at upper-middle crustal depths. [Display omitted] • The attenuation contrasts at Lake Van delimit distinct geological units. • Shallower short wavelength attenuation revealed weak unstable shear zones. • Deeper long wavelength attenuation marked rigid stable shear zones. • This study better constrained crustal segmentation and differential deformation types. [ABSTRACT FROM AUTHOR]

There are numerous methods used nowadays to monitor landslide movements. Of these methods, Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR) are the ones that are most commonly used. In this study, the amounts of movements acquired via these two methods were compared and relations between them were analysed. The Koyulhisar landslide region was selected as the field of study. In this study, 10 Envisat images of the region taken between 2006 and 2008 were evaluated using Persistent Scatterers Interferometric Synthetic Aperture Radar (PSInSAR) technique and annual velocity values at the direction of line of slight at PS points were obtained for the region of interest. The velocity values were then obtained from PSInSAR results and compared with those obtained from six periods of GNSS measurements that were performed between April 2007 and November 2008 on Koyulhisar Landslide area after which the relationship between the two was analysed. Two different movement models from GNSS and PSInSAR results were fit to the landslide region. The velocity values estimated from these movement models for the region were compared and correlation between them was determined. As a conclusion, a high correlation ofr= 0.84 was determined between the models obtained from nine GNSS points, except one point at the city centre, and PSInSAR. [ABSTRACT FROM PUBLISHER]

Objectives: This prospective clinical study aims to evaluate the effectiveness of long-term of anti-tumor necrosis factor-alpha (TNF-α) therapy on arterial stiffness in ankylosing spondylitis. Patients and methods: A total of 28 active ankylosing spondylitis patients (21 males, 7 females; mean age 33.5±9.5 years; range 20 to 52 years) were enrolled. Patients' values for before the initiation of biological therapy and mid-term (24 weeks) evaluation were reported. For further evaluation, this initially reported patients were contacted two years after anti-TNF-α therapy, and their arterial stiffness was assessed by using pulse wave velocity. Results: After two years of anti-TNF-α therapy, despite the significant improvements in patients' symptoms and clinical activity parameters including Bath Ankylosing Spondylitis Disease Activity Index score (4.9±0.9, 1.9±0.5 and 1.8±0.9, p=0.0001), erythrocyte sedimentation rate (35.5±23.1 mm/h, 13.8±9.2 mm/h and 25.0±17.9 mm/h, p=0.0001), and C-reactive protein (2.1±1.6 ng/dL, 0.4±0.3 ng/dL and 0.6±0.9 ng/dL p=0.0001), no significant difference was observed in arterial stiffness parameters (7.9±1.3 meter/second, 7.7±1.3 meter/second and 8.3±1.1 meter/second, p=0.620). Conclusion: In line with the previous 24-week evaluation, the results at two-year follow-up indicates that anti-TNF-α therapy does not improve arterial stiffness in patients with ankylosing spondylitis. [ABSTRACT FROM AUTHOR]

Increased aortic stiffness (AS) has been shown to be an independent risk factor for cardiovascular disease in renal failure and was also found to be associated with even mild renal insufficiency. We investigated the relationship between contrast-induced nephropathy (CIN) and AS parameters such as pulse wave velocity (PWV) and augmentation index (AIx). Patients (n = 440) with stable coronary artery disease (CAD) treated with percutaneous coronary intervention (PCI) were included prospectively (mean age: 60.3 ± 10.3 years). The PWV and AIx were calculated using the single-point method. The PWV, age, diabetes, SYNTAX score, and contrast media dose were independent predictors for CIN (P < .05, for all). The cutoff value for PWV obtained by the receiver–operator characteristic curve analysis was 10.35 m/s for the prediction of CIN (95% confidence interval: 0.838-0.916, sensitivity: 82.1%, specificity: 77.9%, and P < .001). In conclusion, a greater AS pre-PCI may predict CIN development in patients with stable CAD. [ABSTRACT FROM PUBLISHER]

Assessment of potential seismic risk and losses in urban environments is necessary for several purposes ranging from risk mitigation to city and regional planning. It is well known that loss estimation should be performed within an interdisciplinary setting involving earth sciences and engineering. Field experience from recent events worldwide shows that the spatial variability of seismic damage is due to the combined effects of earthquake source properties, local site conditions and structural characteristics. In this study, a scenario-based multi-input damage estimation framework in an urban region was utilized for the Gaziantep city center (southeastern Turkey) that is located in a region of high seismic hazard with no large events in the instrumental era. Initially, a thorough geological and seismo-tectonic assessment of the area was performed followed by estimation of two critical scenario events with moment magnitude (Mw) of 6.5 and 6.6 on nearby active faults. Then, a regional velocity model was compiled from regressions of existing regional geotechnical and seismic data in terms of the V S30 parameter. As the next step, field surveys for the assessment and classification of buildings in the study area were performed followed by vulnerability analyses. As the last step, the mean damage ratios were computed at 198 neighborhoods within the city center. The results indicate not only a high hazard but also high risk in the Gaziantep area due to the combination of close proximity to the faults along with local site effects and building fragilities. • Identification of seismic source characteristics of Gaziantep city, Turkey. • Development of regional seismic velocity model. • Simulation of ground motion records for the selected scenario earthquakes. • Identification of building stock characteristics in the study area and derivation of seismic fragility curves for each building typology. • Estimation of regional seismic damage. [ABSTRACT FROM AUTHOR]

Abstract: Atmospheric deposition is a significant pollution source leading to contamination of remote and clean sites, surface waters and soils. Since persistent organic pollutants (POPs) stay in atmosphere without any degradation, they can be transported and deposited to clean surfaces. Organochlorine pesticides are an important group of POPs which have toxic and harmful effects to living organisms and environment. Therefore, atmospheric deposition levels and characteristics are of importance to determine the pollution quantity of water and soil surfaces in terms of POPs. This study reports the distribution quantities of atmospheric deposition including bulk, dry, wet and air–water exchange of particle and gas phase OCPs as a result of 1-year sampling campaign. Atmospheric deposition distribution showed that the main mechanism for OCPs deposition is wet processes with percentage of 69 of total deposition. OCP compounds' deposition varied according to atmospheric concentration and deposition mechanism. HCH compounds were dominant pesticide species for all deposition mechanisms. HCH deposition constituted the 65% of Σ10OCPs. [Copyright &y& Elsevier]

Highlights: [•] New Moho depth map is presented. [•] Crustal thickness is varying between 24 and 48km. [•] The thinnest crust observed at the western coast of Anatolia. [•] The thickest crust observed at the eastern Anatolia. [•] Uppermost mantle S-wave speed is lower than world average. [ABSTRACT FROM AUTHOR]