Basaltic and Solution Reference Materials for Iron,Copper and Zinc Isotope Measurements

Iron, Cu and Zn stable isotope systems are applied in constraining a variety of geochemical and environmental processes. Secondary reference materials have been developed by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS), in collaboration with other participating laboratories, comprising three solutions (CAGS‐Fe, CAGS‐Cu and CAGS‐Zn) and one basalt (CAGS‐Basalt). These materials exhibit sufficient homogeneity and stability for application in Fe, Cu and Zn isotopic ratio determinations. Reference values were determined by inter‐laboratory analytical comparisons involving up to eight participating laboratories employing MC‐ICP‐MS techniques, based on the unweighted means of submitted results. Isotopic compositions are reported in per mil notation, based on reference materials IRMM‐014 for Fe, NIST SRM 976 for Cu and IRMM‐3702 for Zn. Respective reference values of CAGS‐Fe, CAGS‐Cu and CAGS‐Zn solutions are as follows: δ⁵⁶Fe = 0.83 ± 0.07 and δ⁵⁷Fe = 1.20 ± 0.13, δ⁶⁵Cu = 0.57 ± 0.06, and δ⁶⁶Zn = ?0.79 ± 0.12 and δ⁶⁸Zn = ?1.65 ± 0.24, respectively. Those of CAGS‐Basalt are δ⁵⁶Fe = 0.15 ± 0.07, δ⁵⁷Fe = 0.22 ± 0.10, δ⁶⁵Cu = 0.12 ± 0.08, δ⁶⁶Zn = 0.17 ± 0.13, and δ⁶⁸Zn = 0.34 ± 0.26 (2s).     

Value of Information Introduced by a Resource Model Updating Framework

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.

     

Automatic detection of earthquake-induced ground failure effects through Faster R-CNN deep learning-based object detection using satellite images

Natural Hazards - The seismically induced ground failure is defined as any earthquake-generated process that leads to deformations within a soil medium, which in turn results in permanent...     

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

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.     

Ka/Ku双波段云雷达反演空气垂直运动速度和雨滴谱方法研究及初步应用

在Ka波段云雷达上升级改造建成的Ka/Ku（Ka和Ku波段波长分别为8.9 mm和2.2 cm）双波段云雷达2019年用于华南云降水垂直结构观测,以改进云内动力和微物理参数探测能力。为了利用该双波段云雷达研究华南降水微物理和动力结构,本文提出了基于双波段云雷达回波强度谱密度（S_Z）数据和最优估计技术的云内空气垂直运动速度（V_air）、雨滴谱（DSD）、含水量（LWC）、雨强（R）的反演方法（DWSZ）,雨区衰减的订正方法。利用2019年在广东龙门观测的一次降水过程数据,对比分析了云雷达反演的微物理参数与雨滴谱直接观测量,并检验了云雷达反演的低层空气垂直运动速度,利用反演结果分析了一次混合云过程的V_air与这些微物理参数的垂直结构和相互关系。结果表明:Ka/Ku双波段云雷达合理反演了微降水微物理和动力参数及其垂直分布,经过衰减订正的Ka和Ku波段回波强度偏差明显减小。该双波段云雷达数据可以用于分析0～30 dBZ回波强度的云降水垂直结构。本次过程为混合云降水,对流单体前部存在明显的上升气流,后部存在下沉气流;从平均垂直结构来看:V_air和粒子平均直径（D_m）在2 km高度层到达最大,粒子数密度（N_w）、LWC和R在2 km以下明显增强,粒子直径却减小,水汽凝结过程、雨滴碰并云滴是本次过程的主要机制。这一工作验证了Ka和Ku波段组合的双波段云雷达的可行性,为Ka/Ku波段云雷达技术的推广,单波段云雷达反演算法进一步改进,云降水精细结构分析等提供了基础。     

Triassic warm subduction in northeast Turkey: Evidence from the Ağvanis metamorphic rocks

Within the Tethyan realm, data for the subduction history of the Permo–Triassic Tethys in the form of accretionary complexes are scarce, coming mainly from northwest Turkey and Tibet. Herein we present field geological, petrological and geochronological data on a Triassic accretionary complex, the A?vanis metamorphic rocks, from northeast Turkey. The A?vanis metamorphic rocks form a SSE–NNW trending lozenge‐shaped horst, ～20 km long and ～6 km across, bounded by the strands of the active North Anatolian Fault close to the collision zone between the Eastern Pontides and the Menderes–Taurus Block. The rocks consist mainly of greenschist‐ to epidote‐amphibolite‐facies metabasite, phyllite, marble and minor metachert and serpentinite, interpreted as a metamorphic accretionary complex based on the oceanic rock types and ocean island basaltic, mid‐ocean ridge basaltic and island‐arc tholeiitic affinities of the metabasites. This rock assemblage was intruded by stocks and dikes of Early Eocene quartz diorite, leucogranodiorite and dacite porphyry. Metamorphic conditions are estimated to be 470–540°C and ～0.60–0.90 GPa. Stepwise ⁴⁰Ar/³⁹Ar dating of phengite–muscovite separates sampled outside the contact metamorphic aureoles yielded steadily increasing age spectra with the highest incremental stage corresponding to age values ranging from ～180 to 209 Ma, suggesting that the metamorphism occurred at ≥ 209 Ma. Thus, the A?vanis metamorphic rocks represent the vestiges of the Late Triassic or slightly older subduction in northeast Turkey. Estimated P–T conditions indicate higher temperatures than those predicted by steady state thermal models for average subduction zones, and can best be accounted for by a hot subduction zone, similar to the present‐day Cascadia. Contact metamorphic mineral assemblages around an Early Eocene quartz diorite stock, on the other hand, suggest that the present‐day erosion level was at depths of ～14 km during the Early Eocene, indicative of reburial of the metamorphic rocks. Partial disturbance of white‐mica Ar–Ar age spectra was probably caused by the reburial coupled with heat input by igneous activity, which is probably related to thrusting due to the continental collision between Eastern Pontides and the Menderes–Taurus Block.     

Development of detachable replaceable links for eccentrically braced frames

Eccentrically braced frames (EBFs) can be repaired after a major earthquake by replacing the links. The link replacement is not a straightforward process and is influenced by the type of the link and the amount of residual frame deformations. The past decade has witnessed the development of different types of replaceable links such as end-plated links, web connected links, bolted flange and web spliced links, and collector beam and brace spliced links. All of the developed replaceable link details, except the web connected links, are not suitable for link replacement under residual frame drift. In this paper, a detachable replaceable link detail which is based on splicing the link at its mid-length is proposed. The detail is well suited for installation under residual frame drifts. In addition, the weight and size of the members to be transported and erected are reduced significantly, thereby facilitating the replacement procedure. Performance of this proposed replaceable link is studied by conducting six nearly full scale EBF tests under quasi-static cyclic loading. The link length ratio, type of end-plated mid-splice connection, and the amount of residual drift are considered as test variables. The test results revealed that the inelastic rotation capacity of the detachable replaceable links exceeds the requirements of the AISC Seismic Provisions for Structural Steel Buildings. No failures are observed in the end-plated mid-splice connections demonstrating the potential of the proposed details. The detachable replaceable links are investigated by numerical analysis as well to further validate their applicability and to develop design recommendations.