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The earthquake of 1546 is considered to be one of the largest shocks in the Middle East associated with surface faulting and great loss of life. The examination of contemporary documents shows that this seismic event was a medium magnitude earthquake of Ms about 6.0, in many respects similar to that of the earthquake of 1927, that is, one of those early and grossly exaggerated events which excited widespread interest rather on account of the geographical location than because of their size or special violence. We cpud find no evidence of faulting or excessive damage and no justification to regard this earthquake as one of the most destructive in the Jordan Rift Valley. 相似文献
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Results of repeated precise leveling in several regions indicate that the magnitude of inferred vertical displacements is controlled by the quality of benchmark monumentation. If ignored, such a correlation may lead to an erroneous tectonic interpretation of the computed pattern of motion. 相似文献
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To test erosion and development of bed sculpture in unstable, pulsating shallow flow, three series of experiments were performed in a 10-m flume with flows of Reynolds Number (Re) up to 103, Froude Number (Fr) up to 3.0, and slope up to 2%. In the first series of experiments (59 runs), the bed was rigid (glass flume-bottom), in the second (50 runs) and third (10 runs) series, planar beds were made from well-sorted and poorly sorted sand, respectively. Development of flow surface instability above the rigid bed showed the following stages: smooth surface; small wavelets; well-developed waves; and rough flow. Development of bedform morphology in the second series of tests showed the following sequence: smooth bed; flow-aligned ridge and trough pattern; combined ridge and rhomboid pattern; and rhomboid configuration. In presence of flow instability, ridge patterns form in flows with mean values indicative of laminar-subcritical regime, combined ridge and rhomboid patterns in laminar-supercritical regime, and rhomboid patterns in flows with mean values indicative of transitional turbulent-supercritical regime. The third series of experiments demonstrated transverse segregation of the bed material across the ridges.The results, in line with stability theory, show that laminar and transitional flows already become unstable when and suggest that pulsations may appear in sheet-floods and overland flow, intensifying erosion and transport of sediment. The precise mechanism of origin of the parent kinematic flow configurations instrumental in generation of the ridge and the rhomboid patterns is not yet clear. It may be related to the mechanism operating in transition and generation of turbulence in parallel flows, or flows with a superimposed fluctuation, but other types of hydrodynamic instability are also possible. 相似文献
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Fracture intensity expressed in terms of fracture surface area per volume is rapidly estimated using a stereological equation Sv = 2PL developed in studies of biological and metallurgic systems. Modifications are available for the case of fully oriented, partially oriented and conjugate fractures. 相似文献
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During the rainy season the ephemeral streamcourses of southern Israel are swept by flash floods of low volume and short duration, which produce meander bars, megaripples and ripples, harrow marks, current lineations, obstacle marks, washouts and remnant bars, rhomboid marks, rill marks, rare convolute lamination, imbrication, mud pebbles and polygonal desiccation patterns. The rapid abatement of floods results in a variety of coexisting, interfering and superimposed associations of bed forms, which shed light on some aspects of provenance and origin of alluvial bed forms. 相似文献
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Lineament, joint and drainage density values are obtainable from the number of intersections between the mapped lines and a superimposed test grid or array, using the stereological equation
where x is the density (length per area) and n′ is the number of intersections per unit length of the test array. Circular test grid must be used in order to eliminate the effect of preferred orientation on the n′-values. 相似文献
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