Estimation of the 3D correlation structure of an alluvial aquifer from surface-based multi-frequency ground-penetrating radar reflection data     

Zhiwei Xu  James Irving  Kyle Lindsay  John Bradford  Peimin Zhu  Klaus Holliger 《Geophysical Prospecting》2020,68(2):678-689

Knowledge about the stochastic nature of heterogeneity in subsurface hydraulic properties is critical for aquifer characterization and the corresponding prediction of groundwater flow and contaminant transport. Whereas the vertical correlation structure of the heterogeneity is often well constrained by borehole information, the lateral correlation structure is generally unknown because the spacing between boreholes is too large to allow for its meaningful inference. There is, however, evidence to suggest that information on the lateral correlation structure may be extracted from the correlation statistics of the subsurface reflectivity structure imaged by surface-based ground-penetrating radar measurements. To date, case studies involving this approach have been limited to 2D profiles acquired at a single antenna centre frequency in areas with limited complementary information. As a result, the practical reliability of this methodology has been difficult to assess. Here, we extend previous work to 3D and consider reflection ground-penetrating radar data acquired using two antenna centre frequencies at the extensively explored and well-constrained Boise Hydrogeophysical Research Site. We find that the results obtained using the two ground-penetrating radar frequencies are consistent with each other, as well as with information from a number of other studies at the Boise Hydrogeophysical Research Site. In addition, contrary to previous 2D work, our results indicate that the surface-based reflection ground-penetrating radar data are not only sensitive to the aspect ratio of the underlying heterogeneity, but also, albeit to a lesser extent, to the so-called Hurst number, which is a key parameter characterizing the local variability of the fine-scale structure.  相似文献   

Multimodal water age distributions and the challenge of complex hydrological landscapes     

Nicolas B. Rodriguez  Paolo Benettin  Julian Klaus 《水文研究》2020,34(12):2707-2724

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Ecological–Geochemical Studies of Technogenic Soils in the Flood Plain Landscapes of the Seversky Donets,Lower Don Basin     

T. V. Bauer  V. G. Linnik  T. M. Minkina  S. S. Mandzhieva  D. G. Nevidomskaya 《Geochemistry International》2018,56(10):992-1002

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Traces of ancient geysers preserved in the travertine of Siwaqa,Jordan: conditions of their formation     

Ikhlas Alhejoj  Klaus Bandel  Elias Salameh  Khitam Alzughoul 《Environmental Earth Sciences》2018,77(7):281

A Pleistocene travertine quarrying on a hill in Siwaqa area, central Jordan, excavated solid, well-stratified travertine beds of about 12 m in thickness. The fabric and composition of the travertine indicate original deposition from hot spring water. At present, the area and its surrounding are devoid of any perennial water, except for periodic flood flows that collect at Siwaqa dam 4–5 km to the west of the quarry area, joining the catchment of the River Mujib. The travertine overlies combusted oil shale. The exposed hot spring travertine consists predominantly of well-bedded limestone, interrupted by horizons of chaotic angular debris, indicating ejection from below such as those produced by geysers. The article discusses the origins of the mottled and angular rock fragments, their transportation due to explosive geyser, the conditions and possible causes that produced the pressures leading to steam outbreaks and are responsible for the observed redistribution of travertine layers.  相似文献   

Government-Funded Deep Geophysical Surveys to Encourage Mineral Exploration: Results from the Western Australian “Exploration Incentives Scheme”     

Michael Dentith  Klaus Gessner  Simon Johnson  Ruth Murdie  Perla Pina-Varas  Jessica Spratt  Ian Tyler  Huaiyu Yuan 《《地质学报》英文版》2018,92(Z1):16-17

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Rutile R632 – A New Natural Reference Material for U‐Pb and Zr Determination          下载免费PDF全文

Emelie Axelsson  Jonas Pape  Jasper Berndt  Fernando Corfu  Klaus Mezger  Michael M. Raith 《Geostandards and Geoanalytical Research》2018,42(3):319-338

A new natural rutile reference material is presented, suitable for U‐Pb dating and Zr‐in‐rutile thermometry by microbeam methods. U‐Pb dating of rutile R632 using laser ablation ICP‐MS with both magnetic sector field and quadrupole instruments as well as isotope dilution‐thermal ionisation mass spectrometry yielded a concordia age of 496 ± 2 Ma. The high U content (> 300 μg g^?1) enabled measurement of high‐precision U‐Pb ages despite its young age. The sample was found to have a Zr content of 4294 ± 196 μg g^?1, which makes it an excellent complementary reference material for Zr‐in‐rutile thermometry. Individual rutile grains have homogeneous compositions of a number of other trace elements including V, Cr, Fe, Nb, Mo, Sn, Sb, Hf, Ta and W. This newly characterised material significantly expands the range of available rutile reference materials relevant for age and temperature determinations.  相似文献   

Application of Bayesian Generative Adversarial Networks to Geological Facies Modeling     

Feng  Runhai  Grana  Dario  Mukerji  Tapan  Mosegaard  Klaus 《Mathematical Geosciences》2022,54(5):831-855

Mathematical Geosciences - Geological facies modeling is a key component in exploration and characterization of subsurface reservoirs. While traditional geostatistical approaches are still commonly...  相似文献   

Empirical assessment of rockfall and debris flow risk along the Karakoram Highway,Pakistan     

Ali  Sajid  Haider  Rashid  Abbas  Wahid  Basharat  Muhammad  Reicherter  Klaus 《Natural Hazards》2021,106(3):2437-2460

Natural Hazards - The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section...  相似文献   

Blind Source Separation for Compositional Time Series     

Nordhausen  Klaus  Fischer  Gregor  Filzmoser  Peter 《Mathematical Geosciences》2021,53(5):905-924

Many geological phenomena are regularly measured over time to follow developments and changes. For many of these phenomena, the absolute values are not of interest, but rather the relative information, which means that the data are compositional time series. Thus, the serial nature and the compositional geometry should be considered when analyzing the data. Multivariate time series are already challenging, especially if they are higher dimensional, and latent variable models are a popular way to deal with this kind of data. Blind source separation techniques are well-established latent factor models for time series, with many variants covering quite different time series models. Here, several such methods and their assumptions are reviewed, and it is shown how they can be applied to high-dimensional compositional time series. Also, a novel blind source separation method is suggested which is quite flexible regarding the assumptions of the latent time series. The methodology is illustrated using simulations and in an application to light absorbance data from water samples taken from a small stream in Lower Austria.

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Water level observations from unmanned aerial vehicles for improving estimates of surface water–groundwater interaction          下载免费PDF全文

Filippo Bandini  Michael Butts  Torsten Vammen Jacobsen  Peter Bauer‐Gottwein 《水文研究》2017,31(24):4371-4383

Integrated hydrological models are usually calibrated against observations of river discharge and piezometric head in groundwater aquifers. Calibration of such models against spatially distributed observations of river water level can potentially improve their reliability and predictive skill. However, traditional river gauging stations are normally spaced too far apart to capture spatial patterns in the water surface, whereas spaceborne observations have limited spatial and temporal resolution. Unmanned aerial vehicles can retrieve river water level measurements, providing (a) high spatial resolution; (b) spatially continuous profiles along or across the water body, and (c) flexible timing of sampling. A semisynthetic study was conducted to analyse the value of the new unmanned aerial vehicle‐borne datatype for improving hydrological models, in particular estimates of groundwater–surface water (GW–SW) interaction. Mølleåen River (Denmark) and its catchment were simulated using an integrated hydrological model (MIKE 11–MIKE SHE). Calibration against distributed surface water levels using the Differential Evolution Adaptive Metropolis algorithm demonstrated a significant improvement in estimating spatial patterns and time series of GW–SW interaction. After water level calibration, the sharpness of the estimates of GW–SW time series improves by ~50% and root mean square error decreases by ~75% compared with those of a model calibrated against discharge only.  相似文献