Prediction of Blast-Induced Ground Vibration in an Open-Pit Mine by a Novel Hybrid Model Based on Clustering and Artificial Neural Network     

Nguyen  Hoang  Drebenstedt  Carsten  Bui  Xuan-Nam  Bui  Dieu Tien 《Natural Resources Research》2020,29(2):691-709

Natural Resources Research - Ground vibration (PPV) is one of the hazard effects induced by blasting operations in open-pit mines, which can affect the surrounding structures, particularly the...  相似文献   

Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East   总被引：5，自引：5，他引：0  

John Douglas  Sinan Akkar  Gabriele Ameri  Pierre-Yves Bard  Dino Bindi  Julian J. Bommer  Sanjay Singh Bora  Fabrice Cotton  Boumédiène Derras  Marcel Hermkes  Nicolas Martin Kuehn  Lucia Luzi  Marco Massa  Francesca Pacor  Carsten Riggelsen  M. Abdullah Sandıkkaya  Frank Scherbaum  Peter J. Stafford  Paola Traversa 《Bulletin of Earthquake Engineering》2014,12(1):341-358

This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan.  相似文献   

Editorial for the special issue: extreme events and vulnerability in environment and society     

Thomas Glade  Carsten Felgentreff  Joern Birkmann 《Natural Hazards》2010,55(3):571-576

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Making the EU Emissions Trading System: The European Commission as an entrepreneurial epistemic leader     

Jon Birger Skjærseth  Jørgen Wettestad 《Global Environmental Change》2010,20(2):314-321

The EU has developed the first and largest international emissions trading system in the world. This development is puzzling due to the EU's scepticism to international emissions trading in greenhouse gases (GHGs) in the run-up to the 1997 Kyoto Protocol. This article analyses how the EU ETS was initiated in the first place mainly from the perspectives of Liberal intergovernmentalism (LI) and multi-level governance (MLG). LI emphasises change in the positions of the EU member states as the key to understand what happened and why, whereas MLG opens up for change in the position of supranational entrepreneurial leaders as the key explanation. The main conclusion is that entrepreneurial epistemic leadership exercised by the European Commission was crucial for making the EU ETS. The principal means of leadership involved building up independent expertise on how an EU ETS could be designed, and mobilizing support from state and non-state actors at various levels of decision-making. This type of leadership may be needed more generally to deal with challenges characterized by high scientific uncertainty and social complexity in which learning is pertinent, such as climate change.  相似文献   

Submicromolar Oxygen Profiles at the Oxic–Anoxic Boundary of Temperate Lakes     

Mathias K. Kirf  Christian Dinkel  Carsten J. Schubert  Bernhard Wehrli 《Aquatic Geochemistry》2014,20(1):39-57

Elements involved in biogeochemical cycles undergo rapid turnover at the oxic–anoxic interface of stratified lakes. Here, the presence or absence of oxygen governs abiotic and biotic processes and rates. However, achieving a detailed sampling resolution to precisely locate the oxic–anoxic interface is difficult due to a lack of fast, drift-free sensors in the working range of 10 to a few 1,000 nmol O₂ L^?1. Here, we demonstrate that conventional amperometric and optical microsensors can be used to resolve submicromolar oxygen concentrations in a continuous profiling mode. The amperometric drift was drastically reduced by anoxic preconditioning. In situ offset correction in the anoxic layer and a high amplification scheme allowed for an excellent detection limit of < 10 nmol L^?1. The optical microsensors also showed a similar performance with a detection limit of < 20 nmol L^?1. Their drift stability allowed for a laboratory calibration in combination with a minor in situ anoxic offset correction. The two different sensor systems showed virtually identical profiles during parallel use in stratified lakes. Both sensors were able to resolve the fine-scale structure at the oxic–anoxic interface and revealed hitherto unnoticed extended zones of submicromolar oxygen concentrations even below a steep oxycline. The zones extended up to several meters and showed substantial vertical variability. These results underline the need of a precise localization of the oxic–anoxic interface on a submicromolar scale in order to constrain the relevant aerobic and anaerobic redox processes.  相似文献   

Magnetic anomalies and rock magnetism of basalts from Reykjanes (SW-Iceland)     

Frank Dietze  Agnes Kontny  Ingo Heyde  Carsten Vahle 《Studia Geophysica et Geodaetica》2011,55(1):109-130

This study presents rock magnetic properties along with magnetic field measurements of different stratigraphic and lithologic basalt units from Reykjanes, the southwestern promontory of the Reykjanes peninsula, where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The basaltic fissure eruptions and shield lava of tholeiitic composition (less than 11500 a old) show a high natural remanent magnetization (NRM, J_r) up to 33.6 A/m and high Koenigsberger ratio (Q) up to 52.2 indicating a clear dominance of the NRM compared to the induced part of the magnetization. Pillow basalts and picritic shield lava show distinctly lower J_r values below 10 A/m. Magnetic susceptibility (κ) ranges for all lithologies from 2.5 to 26×10⁻³ SI.  相似文献   

Mechanisms of Archean crust formation inferred from high-precision HFSE systematics in TTGs   总被引：7，自引：0，他引：7  

J. Elis Hoffmann  Carsten Münker  Minik T. Rosing  Dieter Garbe-Schönberg 《Geochimica et cosmochimica acta》2011,75(15):4157-6628

It has been proposed that Archean tonalitic-trondhjemitic-granodioritic magmas (TTGs) formed by melting of mafic crust at high pressures. The residual mineralogy of the TTGs (either (garnet)-amphibolite or rutile-bearing eclogite) is believed to control the trace element budget of TTGs. In particular, ratios of high-field-strength elements (HFSE) can help to discriminate between the different residual lithologies. In order to place constraints on the source mineralogy of TTGs, we performed high-precision HFSE measurements by isotope dilution (Nb, Ta, Zr, Hf) together with Lu-Hf and Sm-Nd measurements on representative, ca. 3.85-2.8 Ga TTGs and related rock types from southern West Greenland, W-India and from the Superior Province. These measurements are complemented by major and trace element data for the TTGs. Texturally homogeneous early Archean (3.85-3.60 Ga old) and Mesoarchean (ca. 3.1-2.8 Ga old) TTGs have both low Ni (<11 ppm) and Cr contents (<20 ppm), indicating that there was little or no interaction with mantle peridotite during ascent. Ratios of Nb/Ta in juvenile Eoarchean TTGs range from ca. 7 to ca. 24, and in juvenile Mesoarchean TTGs from ca. 14 to ca. 27. Even higher Nb/Ta (14-42) were obtained for migmatitic TTGs and intra-crustal differentiates, most likely mirroring further fractionation of Nb from Ta as a consequence of partial melting, fluid infiltration and migmatisation. In the juvenile TTGs, positive correlations between Nb/Ta and Gd/Yb, La/Yb, Sr/Y, Zr/Sm and Zr/Nb are observed. These compositional arrays are best explained by melting of typical Isua tholeiites in both, the rutile-bearing eclogite stability field (>15 kbar, high Nb/Ta) and the garnet-amphibolite stability field (10-15 kbar, low Nb/Ta). With respect to the low end of Nb/Ta found for TTGs, there is currently some uncertainty between the available experimental datasets for amphibole. Independent of these uncertainties, the TTG compositions found here still require the presence of both endmember residues. A successful geological model for the TTGs therefore has to account for the co-occurrence of both low- and high-Nb/Ta TTGs within the same geologic terrane. An additional feature observed in the Eoarchean samples from Greenland is a systematic co-variation between Nb/Ta and initial εHf(t), which is best explained by a model where TTG-melting occured at progressively increasing pressures in a pile of tectonically thickened mafic crust. The elevated Nb/Ta in migmatitic TTGs and intra-crustal differentiates can shed further light on the role of intra-crustal differentiation processes in the global Nb/Ta cycle. Lower crustal melting processes at granulite facies conditions may generate high-Nb/Ta domains in the middle crust, whereas mid-crustal melting at amphibolite facies conditions may account for the low Nb/Ta generally observed in upper crustal rocks.  相似文献   

Natural hazards and resilience: exploring institutional and organizational dimensions of social resilience   总被引：1，自引：1，他引：0  

Gérard Hutter  Christian Kuhlicke  Thomas Glade  Carsten Felgentreff 《Natural Hazards》2013,67(1):1-6

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Delineating subsurface heterogeneity at a loop of River Steinlach using geophysical and hydrogeological methods   总被引：1，自引：1，他引：0  

Kennedy O. Doro  Carsten Leven  Olaf A. Cirpka 《Environmental Earth Sciences》2013,69(2):335-348

Stratigraphic heterogeneity is a key controlling factor for flow and transport in groundwater systems. In this case study, we have combined two- and three-dimensional images of electric resistivity with hydrogeological data to delineate such stratigraphic heterogeneity at a loop of River Steinlach close to Tübingen, Germany, where we estimated spatially varying aquifer parameters using established evaluation techniques. We developed a three-layer stratigraphic model consisting of heterogeneous sandy gravel overlain by a fine alluvium including top soil, and underlain by sandstone weathered at its top. The sandy gravel makes up the aquifer unit while we interpret the sandstone as aquitard. We classified the area into two stratigraphic segments based on resistivity data. The Southern segment consists of a thicker alluvium where the aquifer material contains more clay than in the Northern segment. Two different stratigraphic structures were also delineated at the Southern and Northern segments, respectively. These structures are visible in inversion results as low-resistivity features trending in the SE–NW in the Southern segment and NE–NW in the Northern segment. Both structures may be previous flow paths of River Steinlach, and the low permeability material overlying them may impair flow exchange in the area. We performed slug and pumping tests to estimate the hydraulic conductivity (K) of the aquifer. The K distributions show slight variation with higher values obtained at wells within the Northern segment and close to the river bank. A qualitative comparison of measured hydraulic conductivities with the resistivity distribution shows good agreement of the spatial patterns. The stratigraphic and hydraulic heterogeneities delineated in this work are important for experimental and modeling studies of flow, transport, and hyporheic exchange at the site.  相似文献   

Teleconnections and predictive characteristics of Australian seasonal rainfall   总被引：1，自引：1，他引：0  

Carsten S. Frederiksen  Xiaogu Zheng  Simon Grainger 《Climate Dynamics》2014,43(5-6):1381-1408

A new methodology is proposed that allows patterns of interannual covariability, or teleconnections, between the intraseasonal and slow components of seasonal mean Australian rainfall and the corresponding components in the Southern Hemisphere atmospheric circulation to be estimated. In all seasons, the dominant rainfall–circulation teleconnections in the intraseasonal component are shown to have the characteristic features associated with well-known intraseasonal dynamical and statistical atmospheric modes and their relationship with rainfall. Thus, for example, there are patterns of interannual covariability that reflect rainfall relationships with the intraseasonal Southern Annular Mode, the Madden-Julian Oscillation and wavenumber 3 and 4 intraseasonal modes of variability. The predictive characteristics of the atmospheric circulation–rainfall relationship are shown to reside with the slow components. In all seasons, we find rainfall–circulation teleconnections in the slow components related to the El Niño-Southern Oscillation. Each season also has a coupled mode, with a statistically significant trend in the time series of the atmospheric component that appears to be related to recent observed trends in rainfall. The slow Southern Annular Mode also features in association with southern Australian rainfall, especially during austral winter and spring. There is also evidence of an influence of Indian Ocean sea surface temperature variability on rainfall in southeast Australia during austral winter and spring.  相似文献