Reply to discussion on “Relation between spring-water chemistry and hydrothermal alteration in the Şaplica volcanic rocks, Şebinkarahisar (Giresun,Turkey)” [Journal of Geochemical Exploration, 2007, v. 93, p. 35–46]     

N. Karakaya  M.Ç. Karakaya  M.T. Nalbantçılar  F. Yavuz 《Journal of Geochemical Exploration》2009

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Splash detachment of sand particles under varying contact stress field of wind-driven raindrop impact     

Günay Erpul  Donald Gabriels  Melis Özge Pınar  Çağlar Sagun  Wim Cornelis 《地球表面变化过程与地形》2021,46(14):2870-2883

The effects of wind-driven rain (WDR) on sand detachment were studied under various raindrop obliquities. Results suggested a significant reduction in compressive stress on sand surfaces for a two-dimensional experimental set-up in a wind tunnel. During experiments, sand particles in splash cups were exposed to both wind-free rain (WFR) and WDR driven by horizontal winds of 6.4, 8.9 and 12.8 m s⁻¹ and rainfall intensities of 50, 60, 75 and 90-mm h⁻¹ to assess the sand detachment rate (D, in g m⁻² s⁻¹). The effects of sand moisture state (dry and wet) on the detachment of different-sized particles (0.20–0.50 and 0.50–2.00 mm, respectively) were also tested. Factorial analysis of variance showed that shear and compressive stress components evaluated by horizontal and vertical kinetic energy flux terms (KE_x and KE_y, respectively, in J m⁻² s⁻¹) along with their vector sum (KE_r, in J m⁻² s⁻¹) explained the variation in D. Neither sand size nor sand moisture was statistically significant alone although binary interactions of KE_r, KE_x and KE_y with the sand size and three-way interaction of KE_x, sand size and moisture were statistically significant. These results can be explained by size-dependent variation in sand compressibility and surface friction related to the total stress field developed by a given partition of shear and compressive stresses of wind-driven oblique raindrops (KE_x/KE_y). Further analysis of the variation of the unit sand detachment rate (D_u = D/KE_r = g J⁻¹) with rain inclination (α, in degrees) better revealed the effect of WDR obliquity on D_u that further changed with sand size class and moisture state. Finally, the difference in the resulting stress field differentiable by the oblique raindrop trajectories of the experiment over sand surface significantly affected the non-cohesive particle detachment rates, to some extent interacted with size-dependent compressibility and interface shear strength of sand grains.  相似文献   

Value of Information Introduced by a Resource Model Updating Framework     

Yüksel  Cansın  Minnecker  Corinna  Shishvan  Masoud Soleymani  Benndorf  Jörg  Buxton  Mike 《Mathematical Geosciences》2019,51(7):925-943

A primary concern of the mining industry is to meet production targets, which are required and defined by customers. Deviations from these targets, in terms of quality and quantity, highly affect the economical aspect. Recently, an efficient resource model updating framework concept has been proposed aiming for the improvement of raw material quality control and process efficiency in any type of mining operation. The concept integrates online sensor measurements, obtained during production, into the resource model. In this way, due to the spatial variability, quality attributes of the blocks that will be produced in the next days or weeks are being updated based on real-time measurements. The concept has been applied in a lignite field with the aim of identifying local impurities in a lignite seam and to improve the prediction of coal quality attributes in neighbouring blocks. This paper investigates the added value of using the resource model updating framework by using the value of information analysis. The expected benefit of additional information (integration of the online sensor measurements into the resource model) is compared to a case where there is no additional information integrated into the process. These benefits are evaluated based on the economic impact determined by applying the resource model updating framework in mine planning.

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Precipitable water vapor (PWV) estimations from the site of the Eastern Anatolia Observatory<Superscript>∗</Superscript> (DAG), a new astronomical observatory in Turkey     

Sacit Özdemir  Cahit Yeşilyaprak  Bahadır Aktuğ  Derya Öztürk  Deniz Çoker  Recep Balbay 《Experimental Astronomy》2018,46(2):323-336

We present preliminary statistics on the precipitable water vapor (PWV) content over the Karakaya Hills in Erzurum city, where the largest optical and near-infrared astronomical telescope in Turkey will be operated. Since the observatory will observe in the near-infrared (NIR), it is intended to perform PWV measurements of the atmosphere above the site by using signal delays in Global Positioning System (GPS) communication. The analysis of the GPS data recorded on the summit for almost one year shows that the atmosphere over the site of the observatory, which has an altitude of 3170 m, has favorable conditions for NIR observations. From GPS measurements, we report that the site had an average PWV of 3.2 mm and a median PWV of 2.7 mm between October 6, 2016, and June 15, 2017. We also present the time dependency of the PWV content and the correlations between the amount of PWV and the other meteorological records gathered from radiosonde flights and ground-based measurements.  相似文献   

Local magnitude scale for earthquakes in Turkey     

T. Kılıç  L. Ottemöller  J. Havskov  K. Yanık  Ö. Kılıçarslan  F. Alver  M. Özyazıcıoğlu 《Journal of Seismology》2017,21(1):35-46

Based on the earthquake event data accumulated by the Turkish National Seismic Network between 2007 and 2013, the local magnitude (Richter, Ml) scale is calibrated for Turkey and the close neighborhood. A total of 137 earthquakes (Mw?>?3.5) are used for the Ml inversion for the whole country. Three Ml scales, whole country, East, and West Turkey, are developed, and the scales also include the station correction terms. Since the scales for the two parts of the country are very similar, it is concluded that a single Ml scale is suitable for the whole country. Available data indicate the new scale to suffer from saturation beyond magnitude 6.5. For this data set, the horizontal amplitudes are on average larger than vertical amplitudes by a factor of 1.8. The recommendation made is to measure Ml amplitudes on the vertical channels and then add the logarithm scale factor to have a measure of maximum amplitude on the horizontal. The new Ml is compared to Mw from EMSC, and there is almost a 1:1 relationship, indicating that the new scale gives reliable magnitudes for Turkey.  相似文献   

Isochron‐burial dating of glaciofluvial deposits: First results from the Swiss Alps          下载免费PDF全文

Naki Akçar  Susan Ivy‐Ochs  Vasily Alfimov  Fritz Schlunegger  Anne Claude  Regina Reber  Marcus Christl  Christof Vockenhuber  Andreas Dehnert  Meinert Rahn  Christian Schlüchter 《地球表面变化过程与地形》2017,42(14):2414-2425

In this study, we use isochron‐burial dating to date the Swiss Deckenschotter, the oldest Quaternary deposits of the northern Alpine Foreland. Concentrations of cosmogenic ¹⁰Be and ²⁶Al in individual clasts from a single stratigraphic horizon can be used to calculate an isochron‐burial age based on an assumed initial ratio and the measured ²⁶Al/¹⁰Be ratio. We suggest that, owing to deep and repeated glacial erosion, the initial isochron ratio of glacial landscapes at the time of burial varies between 6.75 and 8.4. Analysis of 22 clasts of different lithology, shape, and size from one 0.5 m thick gravel bed at Siglistorf (Canton Aargau) indicates low nuclide concentrations: <20 000 ¹⁰Be atoms/g and <150 000 ²⁶Al atoms/g. Using an ²⁶Al/¹⁰Be ratio of 7.6 (arithmetical mean of 6.75 and 8.4), we calculate a mean isochron‐burial age of 1.5 ± 0.2 Ma. This age points to an average bedrock incision rate between 0.13 and 0.17 mm/a. Age data from the Irchel, Stadlerberg, and Siglistorf sites show that the Higher Swiss Deckenschotter was deposited between 2.5 and 1.3 Ma. Our results indicate that isochron‐burial dating can be successfully applied to glaciofluvial sediments despite very low cosmogenic nuclide concentrations. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

The use of 3D modeling for the prediction of the seismic demands on the gravity dams          下载免费PDF全文

M. Bybordiani  Y. Arıcı 《地震工程与结构动力学》2017,46(11):1769-1789

Seismic behavior of gravity dams has long been evaluated using a representative two‐dimensional (2D) system. Formulated for the gravity dams built in wide canyons, the assumption is nevertheless utilized extensively for almost all concrete dams due to the established procedures as well as the expected computational costs of a three‐dimensional model. However, a significant number of roller‐compacted concrete dams, characterized as such systems, do not conform to the basic assumptions of these methods by violating the conditions on canyon dimensions and joint‐spacing/details. Based on the premise that the 2D modeling assumption is overstretched for practical purposes in a variety of settings, the purpose of this study is to critically evaluate the use of 2D modeling for the prediction of the seismic demands on these systems. Using a rigorous soil–structure interaction approach, the difference between the two and three‐dimensional response for gravity dams was investigated first in the frequency domain for a range of canyon widths and foundation to dam moduli ratios. Then, the time domain differences between the crest displacements and the maximum principal stress were obtained using 70 different ground motions in order to show the possible bias introduced into the analysis results due to the modeling approach. The results of the study show that even for relatively wide canyons, the 2D analysis can lead to misleading predictions. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Replaceable links with direct brace attachments for eccentrically braced frames          下载免费PDF全文

Mehmet Bakır Bozkurt  Cem Topkaya 《地震工程与结构动力学》2017,46(13):2121-2139

This paper reports findings of an experimental study conducted on replaceable links for steel eccentrically braced frames (EBFs). A replaceable link detail which is based on splicing the directly connected braces and the beam outside the link is proposed. This detail eliminates the need to use hydraulic jacks and flame cutting operations for replacement purposes. Performance of this proposed replaceable link was studied by conducting eight nearly full‐scale EBF tests under quasi‐static cyclic loading. The link length ratio, stiffening of the link, loading protocol, connection type, bolt pretension, gap size of splice connections, and demand‐to‐capacity ratios of members were considered as the prime variables. The specimens primarily showed two types of failure modes: link web fracture and fracture of the flange at the link‐to‐brace connection. No failures were observed at the splice connections indicating that the proposed replaceable link detail provides an excellent response. The inelastic rotation capacity provided by the replaceable links satisfied the requirements of the AISC Seismic Provisions for Structural Steel Buildings (AISC341–10). The overstrength factor of the links exceeded 2.0, which is larger than the value assumed for EBF links by design provisions. The high level of overstrength resulted in brace buckling in one of the specimens demonstrating the importance of overstrength factor used for EBF links. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

An improved earthquake catalogue (<Emphasis Type="Italic">M</Emphasis> ≥ 4.0) for Turkey and its near vicinity (1900–2012)     

F. Tuba Kadirioğlu  Recai F. Kartal  Tuğbay Kılıç  Doğan Kalafat  Tamer Y. Duman  Tuba Eroğlu Azak  Selim Özalp  Ömer Emre 《Bulletin of Earthquake Engineering》2018,16(8):3317-3338

Many catalogues, agency reports and research articles have been published on seismicity of Turkey and its surrounding since 1950s. Given existing magnitude heterogeneity, erroneous information on epicentral location, event date and time, this past published data however is far from fulfilling the required standards. Paucity of a standardized format in the available catalogues have reinforced the need for a refined and updated catalogue for earthquake related hazard and risk studies. During this study, ~37,000 earthquakes and related parametric data were evaluated by utilizing more than 41 published studies and, an integrated database was prepared in order to analyse all parameters acquired from the catalogues and references for each event. Within the scope of this study, the epicentral locations of M ≥ 5.0 events were firstly reappraised based on the updated Active Fault Map of Turkey. An improved catalogue of 12.674 events for the period 1900–2012 was as a result recompiled for the region between 32–45N° and 23–48E° by analyzing in detail accuracy of all seismological parameters available for each event. The events consist of M ≥ 4.0 are reported in several magnitude scales (e.g. moment magnitude, M_w; surface wave magnitude, M_S; body-wave magnitude m_b; local magnitude M_L and duration magnitude M_d) whereas the maximum focal depth reaches up to 225-km. In order to provide homogenous data, the improved catalogue is unified in terms of M_w. Fore-and aftershocks were also removed from the catalogue and completeness analyses were performed both separately for various tectonic sources and as a whole for the study region of interest. Thus, the prepared homogenous and declustered catalogue consisting of 6573 events provides the basis for a reliable input to the seismic hazard assessment studies for Turkey and its surrounding areas.  相似文献   

Evolution of seismic hazard maps in Turkey     

S. Akkar  T. Azak  T. Çan  U. Çeken  M. B. Demircioğlu Tümsa  T. Y. Duman  M. Erdik  S. Ergintav  F. T. Kadirioğlu  D. Kalafat  Ö. Kale  R. F. Kartal  K. Kekovalı  T. Kılıç  S. Özalp  S. Altuncu Poyraz  K. Şeşetyan  S. Tekin  A. Yakut  M. T. Yılmaz  M. S. Yücemen  Ö. Zülfikar 《Bulletin of Earthquake Engineering》2018,16(8):3197-3228

A review on the historical evolution of seismic hazard maps in Turkey is followed by summarizing the important aspects of the updated national probabilistic seismic hazard maps. Comparisons with the predecessor probabilistic seismic hazard maps as well as the implications on the national design codes conclude the paper.  相似文献