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11.
Efficiency of Partially Penetrating Wells 总被引：1，自引：0，他引：1
Yaron M. Sternberg 《Ground water》1973,11(3):5-8
12.
Bar Elisha Yaron Katzir Andrew R. C. Kylander‐Clark Tzahi Golan Matthew A. Coble 《Journal of Metamorphic Geology》2019,37(5):591-610
Collision‐related granitoid batholiths, like those of the Hercynian and Himalayan orogens, are mostly fed by magma derived from metasedimentary sources. However, in the late Neoproterozoic calcalkaline (CA) batholiths of the Arabian–Nubian Shield (ANS), which constitutes the northern half of the East African orogen, any sedimentary contribution is obscured by the juvenile character of the crust and the scarcity of migmatites. Here, we use paired in situ LASS‐ICP‐MS measurements of U–Th–Pb isotope ratios and REE contents of monazite and xenotime and SHRIMP‐RG analyses of separated zircon to demonstrate direct linkage between migmatites and granites in the northernmost ANS. Our results indicate a single prolonged period of monazite growth at 640–600 Ma, in metapelites, migmatites and peraluminous granites of three metamorphic suites: Abu‐Barqa (SW Jordan), Roded (S Israel) and Taba–Nuweiba (Sinai, Egypt). The distribution of monazite dates and age zoning in single monazite grains in migmatites suggest that peak thermal conditions, involving partial melting, prevailed for c. 10 Ma, from 620 to 610 Ma. REE abundances in monazite are well correlated with age, recording garnet growth and garnet breakdown in association with the prograde and retrograde stages of the melting reactions, respectively. Xenotime dates cluster at 600–580 Ma, recording retrogression to greenschist facies conditions as garnet continued to destabilize. Phase equilibrium modelling and mineral thermobarometry yield P–T conditions of ~650–680°C and 5–7 kbar, consistent with either water‐fluxed or muscovite‐breakdown melting. The expected melt production is 8–10 vol.%, allowing a melt connectivity network to form leading to melt segregation and extraction. U–Pb ages of zircon rims from leucosomes indicate crystallization of melt at 610 ± 10 Ma, coinciding with the emplacement of a vast volume of CA granites throughout the northern ANS, which were previously considered post‐collisional. Similar monazite ages (c. 620 Ma) retrieved from the amphibolite facies Elat schist indicate that migmatites are the result of widespread regional rather than local contact metamorphism, representing the climax of the East African orogenesis. 相似文献
13.
Making a distinction between partial melting and subsolidus segregation in amphibolite facies migmatites is difficult. The only significant melting reactions at lowpressures, either vapour saturated or muscovite dehydration melting, do not produce melanocratic peritectic phases. If protoliths are Si-rich and K-poor, then peritectic sillimanite and K-feldspar will form in scarce amounts, and may be lost by retrograde rehydration. The Roded migmatites of southern Israel (northernmost Arabian Nubian Shield) formed at P = 4.5 ± 1 kbar and T ≤ 700 °C and include Si-rich, K-poor paragneissic paleosome and trondhjemitic leucosomes. The lack of K-feldspar in leucosomes was taken as evidence for the non-anatectic origin of the Roded migmatites (Gutkin and Eyal, Isr J Earth Sci 47:117, 1998). It is shown here that although the Roded migmatites experienced significant post-peak deformation and recrystallization, microstructural evidence for partial melting is retained. Based on these microstructures, coupled with pseudosection modelling, indicators of anatexis in retrograded migmatites are established. Phase diagram modelling of neosomes shows the onset of muscovite dehydration melting at 4.5 kbar and 660 °C, forming peritectic sillimanite and K-feldspar. Adjacent non-melted paleosomes lack muscovite and would thus not melt by this reaction. Vapour saturation was not attained, as it would have formed cordierite that does not exist. Furthermore, vapour saturation would not allow peritectic K-feldspar to form, however K-feldspar is ubiquitous in melanosomes. Direct petrographic evidence for anatexis is rare and includes euhedral plagioclase phenocrysts in leucosomes and quartz-filled embayments in corroded plagioclase at leucosome-melanosome interfaces. In deformed and recrystallized rocks muscovite dehydration melting is inferred by: (1) lenticular K-feldspar enclosed by biotite in melanosomes, (2) abundant myrmekite in leucosomes, (3) muscovite–quartz symplectites after sillimanite in melanosomes and associated with myrmekite in leucosomes. While peritectic K-feldspar formed in melanosomes by muscovite dehydration melting reaction, K-feldspar crystallizing from granitic melt in adjacent leucosome was myrmekitized. Excess potassium was used in rehydration of sillimanite to muscovite. 相似文献
14.
The complementary mild-slope equation (CMSE) is a depth-integrated equation, which models refraction and diffraction of linear time-harmonic water waves. For 2D problems, it was shown to give better agreements with exact linear theory compared to other mild-slope (MS) type equations. However, no reference was given to 3D problems. In contrast to other MS-type models, the CMSE is derived in terms of a stream function vector rather than in terms of a velocity potential. For the 3D case, this complicates the governing equation and creates difficulties in formulating an adequate number of boundary conditions. In this paper, the CMSE is re-derived using Hamilton's principle from the Irrotational Green–Naghdi equations with a correction for the 3D case. A parabolic version of it is presented as well. The additional boundary conditions needed for 3D problems are constructed using the irrotationality condition. The CMSE is compared with an analytical solution and wave tank experiments for 3D problems. The results show very good agreement. 相似文献
15.
Flow to Wells in the Presence of Radial Discontinuities 总被引：1，自引：0，他引：1
Yaron M. Sternberg 《Ground water》1969,7(6):17-20
16.
Stav Shapira Tsafrir Levi Yaron Bar-Dayan Limor Aharonson-Daniel 《Natural Hazards》2018,91(3):1059-1074
The use of casualty modeling in the field of disaster management is well established. Nevertheless, it is currently based almost exclusively on damage to the built environment and fails to consider additional factors that may influence the number of casualties in a given event, such as behavioral features of the exposed population. The present study has taken an innovative approach and integrated behavioral traits of residents in a high-risk area in northern Israel, near the Dead Sea Transform, into a well-known casualty estimation simulation. The expected behavioral characteristics of residents during an earthquake, in city sectors with different socioeconomic rankings, were assessed using a designated survey and were applied into the casualty estimation process. In order to test the sensitivity of the behavioral factor, twelve synthetic earthquake scenarios were designed. The results shed light on the relationship between specific behavioral strategies and casualty projections and suggest that loss estimation models that do not take behavioral factors into account may overestimate the projected number of casualties. Households with low socioeconomic status were found to be more vulnerable in terms of risk of injury and death compared with those ranked higher. The present study shows the importance of raising public awareness regarding proper behavior prior to and during the event which can help increase resilience of communities, mitigate risks and losses and ultimately save lives. Further implications of these results and possible ways of improving casualty modeling and community resilience are also discussed. 相似文献
17.
Yaron Finzi Hans Muhlhaus Lutz Gross Artak Amirbekyan 《Pure and Applied Geophysics》2013,170(1-2):13-25
In seismically active regions, faults nucleate, propagate, and form networks that evolve over time. To simulate crustal faulting processes, including the evolution of fault-zone properties, a rheological model must incorporate concepts such as damage rheology that describe the various stages of the seismic cycle (strain localization, subcritical crack growth and macroscopic failure) while accounting for material degradation and healing and off-fault deformation. Here we study the fundamental patterns of strain-localisation within the framework of a continuum damage rheology by performing a shear band analysis (linear instability analysis) and comparing predictions of shear band orientations with numerical results of the nonlinear problem. We find (analytically and numerically) that the angle between the shear band and the less compressive (transverse) direction is between 47° in compression tests with a strain ratio of 0.25 (highly confined compression test), and 60° for a strain ratio higher than 1.4 (axial compression and transverse extension). In addition we find that shear bands exhibit local dilation (I 1 > 0) in a wide range of strain ratios excluding only simulations with highly confined compression (which yield compacting shear bands or non-localized deformation). Finally, we discuss the applicability of the damage model for simulating deformation in the seismogenic, brittle crust. 相似文献
18.
Structural Properties and Deformation Patterns of Evolving Strike-slip Faults: Numerical Simulations Incorporating Damage Rheology 总被引：1，自引：0，他引：1
Yaron Finzi Elizabeth H. Hearn Yehuda Ben-Zion Vladimir Lyakhovsky 《Pure and Applied Geophysics》2009,166(10-11):1537-1573
We present results on evolving geometrical and material properties of large strike-slip fault zones and associated deformation fields, using 3-D numerical simulations in a rheologically-layered model with a seismogenic upper crust governed by a continuum brittle damage framework over a viscoelastic substrate. The damage healing parameters we employ are constrained using results of test models and geophysical observations of healing along active faults. The model simulations exhibit several results that are likely to have general applicability. The fault zones form initially as complex segmented structures and evolve overall with continuing deformation toward contiguous, simpler structures. Along relatively-straight mature segments, the models produce flower structures with depth consisting of a broad damage zone in the top few kilometers of the crust and highly localized damage at depth. The flower structures form during an early evolutionary stage of the fault system (before a total offset of about 0.05 to 0.1 km has accumulated), and persist as continued deformation localizes further along narrow slip zones. The tectonic strain at seismogenic depths is concentrated along the highly damaged cores of the main fault zones, although at shallow depths a small portion of the strain is accommodated over a broader region. This broader domain corresponds to shallow damage (or compliant) zones which have been identified in several seismic and geodetic studies of active faults. The models produce releasing stepovers between fault zone segments that are locations of ongoing interseismic deformation. Material within the fault stepovers remains damaged during the entire earthquake cycle (with significantly reduced rigidity and shear-wave velocity) to depths of 10 to 15 km. These persistent damage zones should be detectable by geophysical imaging studies and could have important implications for earthquake dynamics and seismic hazard. 相似文献
19.
On symmetrical three-dimensional datum conversion 总被引：2，自引：0，他引：2
A 3-D similarity transformation is frequently used to convert GPS-WGS84-based coordinates to those in a local datum using
a set of control points with coordinate values in both systems. In this application, the Gauss-Markov (GM) model is often
employed to represent the problem, and a least-squares approach is used to compute the parameters within the mathematical
model. However, the Gauss–Markov model considers the source coordinates in the data matrix (A) as fixed or error-free; this is an imprecise assumption since these coordinates are also measured quantities and include
random errors. The errors-in-variables (EIV) model assumes that all the variables in the mathematical model are contaminated
by random errors. This model may be solved using the relatively new total least-squares (TLS) estimation technique, introduced
in 1980 by Golub and Van Loan. In this paper, the similarity transformation problem is analyzed with respect to the EIV model,
and a novel algorithm is described to obtain the transformation parameters. It is proved that even with the EIV model, a closed
form Procrustes approach can be employed to obtain the rotation matrix and translation parameters. The transformation scale
may be calculated by solving the proper quadratic equation. A numerical example and a practical case study are presented to
test this new algorithm and compare the EIV and the GM models. 相似文献
20.