Strain localization in sandstone during embryonic stages of shear-zone evolution     

Yoram Katz  Ram Weinberger 《地学学报》2005,17(4):311-316

Geometric analysis of nested Riedel structures was used to identify and quantify strain localization processes within faulted Navajo sandstone. The analysis shows systematic deviation from the basic Riedel geometry complying with the Mohr–Coulomb criterion. Using cross-cutting relations amongst deformation bands within the Riedel structures, and comparing the orientations of the deformation bands to theoretical strain calculations, we identify two coupling deformation mechanisms involved in the early stages of shear-zone evolution, namely, granular flow and discrete faulting. Both mechanisms localize during strain accumulation, and the granular flow facilitates considerable change in the initial geometry of the Riedel structures. The analysis demonstrates a systematic sequence, by which new Riedel structures form after a constant amount of shear strain takes place in the sandstone. Analysis further indicates that granular flow is the major deformation mechanism during early stages of shear-zone evolution and discrete faulting is the dominant mechanism during later deformation stages.  相似文献   

Fracture and bedding plane control on groundwater flow in a chalk aquitard     

Menachem Weiss  Yoram Rubin  Eilon Adar  Ronit Nativ 《Hydrogeology Journal》2006,14(7):1081-1093

Shallow groundwater in the northern Negev desert of Israel flows preferentially through a complex system of discontinuities. These discontinuities intersect what would otherwise be a massive, low-conductivity, high-porosity Eocene chalk. Vertical fractures and horizontal bedding planes were observed and mapped along approximately 1,200 m of scanline, 600 m of core and 30 two-dimensional trace planes. A bimodal distribution of size exists for the vertical fractures which occur as both single-layer fractures and multi-layer fractures. A bimodal distribution of log transmissivity was observed from slug tests conducted in packed-off, vertical intervals within the saturated zone. The different flow characteristics between the horizontal bedding planes and vertical-type fractures appear to be the cause of the bimodality. Two distinct conceptual models (discrete fracture network) were developed based on the fracture orientation, size, intensity and transmissivity statistics derived from field data. A correlation between fracture size and hydraulic aperture was established as the basis for calibrating the simulated model transmissivity to the field observations. This method of defining transmissivity statistically based on prior information is shown to be a reasonable and workable alternative to the usual conjecture approach towards defining transmissivity in a fractured-rock environment.  相似文献   

Using a Convection Model to Predict Altitudes of White Stork Migration Over Central Israel     

Judy Shamoun-Baranes  Olivier Liechti  Yoram Yom-Tov  Yossi Leshem 《Boundary-Layer Meteorology》2003,107(3):673-681

Soaring migrants such as storks, pelicans and large birds of prey rely on thermal convection during migration. The convection model ALPTHERM was designed to predict the onset, strength, duration and depth of thermal convection for varying topographies for glider pilots, based on atmospheric conditions at midnight. We tested ALPTHERM predictions as configured for two topographies of central Israel, the Coastal Plains and the Judean and Samarian Mountains in order to predict altitudes of migrating white storks (Ciconia ciconia). Migrating flocks of white storks were tracked with a motorized glider, to measure maximum altitudes of migration during spring 2000. A significant positive correlation was found between the maximum daily altitudes of migration measured and the predicted upper boundary of thermal convection for the Coastal Plains and Samarian Mountains. Thirty-minute predictions for the Coastal Plains and Samarian Mountains correlated positively with measured maximum migration altitudes per thermal. ALPTHERM forecasts can be used to alter flight altitudes in both civil and especially military aviation and reduce the hazard of serious aircraft collisions with soaring migrants.  相似文献   

Using inverse modeling and hierarchical cluster analysis for hydrochemical characterization of springs and Talkhab River in Tang-Bijar oilfield,Iran     

Yasaman Rafighdoust  Yoram Eckstein  Reza Moussavi Harami  Mohamad Hosein Mahmudy Gharaie  Asadollah Mahboubi 《Arabian Journal of Geosciences》2016,9(3):241

Hierarchical cluster analysis (HCA) and inverse modeling (PH REdox EQuilibrium (in C language) (PHREEQC)) were simultaneously useful approaches in interpreting surface water hydrochemistry within Talkhab River in the Tang-Bijar oilfield, Iran, where large uncertainties exist in the understanding of the water quality system. Q-mode HCA applied to the data revealed three major surface water associations distinguished on the basis of the major causes of variation in the hydrochemistry. The three water groups were classified as upstream waters (group 1: Ca–SO₄), intermediate waters (group 2: Ca–SO₄–Cl), and downstream waters (group 3: Na–Cl). Geochemical reaction models were constructed using PHREEQC to establish the reactions associated with the different mineral phases through inverse modeling. The hydrochemical compositions of the water groups and the mass balance calculations indicate that the dominant processes and reactions responsible for the hydrochemical evolution in the system are (1) dissolution of evaporites, (2) precipitation of carbonate minerals, (3) silicate weathering reactions, (4) limited mixing with saline water, and (5) ion exchange.  相似文献   

Helicopter Supported Photogrammetric Survey of Ramsberg Castle     

G. Eckstein  & J. Peipe 《The Photogrammetric Record》1996,15(87):447-453

Ramsberg Castle is to be restored and renovated to allow a new use of the building. This requires extensive structural and architectural analyses based upon metric documentation. The façades of the castle were recorded photogrammetrically. Photography from the ground was impossible due to the steep terrain on three sides of the building. For this reason, the photographs were taken from a helicopter. A 4 × 5 inch Linh of Metrika réseau camera was used.
Because of the adverse topography, only a few control points could be determined by on-site theodolite measurement. Therefore the control network was achieved by means of photogrammetric bundle triangulation. Stereorestitution was performed using an analytical plotter connected with a CAD system. Drawings at 1:50 scale were then derived from the as-built CAD model.  相似文献   

Optimal station keeping by electric propulsion with thrust operation constraints     

M. C. Eckstein 《Celestial Mechanics and Dynamical Astronomy》1980,21(2):129-147

The orbit of a geostationary satellite has to be corrected from time to time in order to compensate for the effects of various perturbations. This is usually done by means of a system of thrusters mounted on the satellite. In this paper a method is developed to find the optimal thrusting strategy for the case of an electric propulsion system under given limitations on thrust magnitude and operation times. Optimization techniques are applied to minimize a cost function which is a weighted combination of fuel consumption and station keeping errors.Proceedings of the Sixth Conference on Mathematical Methods in Celestial Mechanics held at Oberwolfach (West Germany) from 14 to 19 August, 1978.  相似文献   

On the automatic interpretation of direct current resistivity soundings     

Ginzburg  Avihu  Loewenthal  Dan  Shoham  Yoram 《Pure and Applied Geophysics》1976,114(6):983-995

A method for the automatic inversion of resistivity soundings is presented. The procedure consists of two main stages. First, application of linear filters which transforms the apparent resistivity curve into the kernel function, and vice versa. In the second stage the first and second derivatives of the kernel function are calculated and used in a second-order modified Newton-Raphson iterative fitting procedure. The model obtained is optimal in the least squares sense. The method has been tried on some field examples and produced resistivity models which show a good agreement with the geological well logs.  相似文献   

Transboundary aquifers: conceptual models for development of international law   总被引：2，自引：1，他引：1  

Eckstein Y  Eckstein GE 《Ground water》2005,43(5):679-690

More than one-half of the world's population is dependent on ground water for everyday uses such as drinking, cooking, and hygiene. In fact, it is the most extracted natural resource in the world. As a result of growing populations and expanding economies, many aquifers today are being depleted while others are being contaminated. Notwithstanding the world's considerable reliance on this resource, ground water resources have long received only secondary attention as compared to surface water, especially among legislatures and policymakers. Today, while there are hundreds of treaties governing transboundary rivers and lakes, there is only one international agreement that directly addresses a transboundary aquifer. Given that many of the aquifers on which humanity so heavily relies cross international borders, there is a considerable gap in the sound management, allocation, and protection of such resources. In order to prevent future disputes over transboundary aquifers and to maximize the beneficial use of this resource, international law must be clarified as it applies to transboundary ground water resources. Moreover, it must be defined with a firm basis in sound scientific understanding. In this paper we offer six conceptual models is which ground water resources can have transboudary consequences. The models are intended to help in assessing the applicability and scientific soundness of existing and proposed rules governing transboundary ground water resources. In addition, we consider the development of international law as it applies to ground water resources and make recommendations based on the models and principles of hydrogeology. The objective is the development of clear, logical, and science-based norms of state conducts as they relate to aquifers that traverse political boundaries.  相似文献   

Bücher- und Zeitschriftenschau     

H. Stremme  Otto Wilckens  C. Gagel  Steinmann  H. -Ed. Eckstein 《International Journal of Earth Sciences》1921,12(1-2):91-97

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Is use of oil-field brine as a dust-abating agent really benign? Tracing the source and flowpath of contamination by oil brine in a shallow phreatic aquifer     

Yoram Eckstein 《Environmental Earth Sciences》2011,63(1):201-214

In Ohio, 1985 H.R. Bill 501 authorizes the local authorities to issue permits to use oil-field brine surface spreading as a dust and ice control agent. Such permits are usually given without any necessary hydrogeological expertise as to the potential impact on the shallow aquifers, particularly if the brine spreading occurs in a recharge area. One such case occurred recently in the southwestern suburb of the City of Wooster, OH, USA, where a group of home owners were seeking judicial relief when their water wells began yielding salty water as a result of brine spreading on a nearby large open storage area for oil and gas well drilling supplies. The defendant, owner of the storage yard, acted in accordance with the permit issued by the local authorities. Yet, decentralized decision making and an increased emphasis on local and citizen involvement have created a gap between science and society. The local authorities were not required by law to condition the issuance of the permit on an analysis of the potential environmental impact. The decision to issue that permit was made purely on non-scientific grounds. Therefore, the residents had no choice but to embark on a costly process of proving the damages, causation, and liability in court of law. During the protracted, 6-year long conflict, an extensive hydrogeological and hydrochemical data set (including stable isotopes’ analyses along with the complete chemical analyses of major and minor constituents) was amassed at a great cost to both sides. The following article presents the hydrogeological and hydrochemical interpretation of this data set. In addition, the case illustrates a glaring deficiency in the Ohio, 1985 H.R. Bill 501, and one pitfall in the “politically correct” philosophy of delegating decision-making process entirely to the non-professional local authorities.  相似文献