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N. N. Ambraseys 《Journal of Seismology》1997,1(3):289-299
In this paper we assess the size and effects of the earthquakes of 12 May 1866, and 24 January 1916 in Anatolia (Turkey). We show that these events had a magnitude Ms 7.2 and that the former was associated with a 45-km long surface fault break along the north-east part of the East Anatolian Fault Zone. These two earthquakes are chosen among others in order to demonstrate how easy it is to miss out large earthquakes of the historical, even of the early instrumental period, and to draw the incompleteness of many existing catalogues to the attention of those who use them for the estimation of slip rates and the assessment of seismic hazard. Of the two earthquakes studied here, the former was only vaguely known and the latter is not included in Gutenberg and Richter's catalogue. 相似文献
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G. D. Nastrom 《Annales Geophysicae》1997,15(6):786-796
The spectral width observed by Doppler radars can be due to several effects including the atmospheric turbulence within the radar sample volume plus effects associated with the background flow and the radar geometry and configuration. This study re-examines simple models for the effects due to finite beam-width and vertical shear of the horizontal wind. Analytic solutions of 1- and 2-dimensional models are presented. Comparisons of the simple 2-dimensional model with numerical integrations of a 3-dimensional model with a symmetrical Gaussian beam show that the 2-dimensional model is usually adequate. The solution of the 2-dimensional model gives a formula that can be applied easily to large data sets. Analysis of the analytic solutions of the 2-dimensional model for off-vertical beams reveals a term that has not been included in mathematical formulas for spectral broadening in the past. This term arises from the simultaneous effects of the changing geometry due to curvature within a finite beamwidth and the vertical wind shear. The magnitude of this effect can be comparable to that of the well-known effects of beam-broadening and wind shear, and since it can have either algebraic sign, it can significantly reduce (or increase) the expected spectral broadening, although under typical conditions it is smaller than the beam-broadening effect. The predictions of this simple model are found to be consistent with observations from the VHP radar at White Sands Missile Range, NM. 相似文献
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The evolution of views and practical decisions regarding the problem of collecting payment for the use of surface waters with regard to their quality in the former USSR and present-day Ukraine is discussed. A simple and feasible method is proposed for differentitation of regional (basin) rates of payment for the use of surface water in Ukraine with allowance made for its quality assessed based on a system of environmental classifications. 相似文献