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401.
Gao Yuan Zhou Huilan Zheng Sihua Ma Lin Che Shi and Liu WeihongGraduate School University of Science Technology of China Beijing China Center for Analysis Prediction SSB Beijing China 《中国地震研究》1998,(2)
In an earthquake catalog,the source depth of earthquakes is one of the most basic parameters; however it is also one of the most difficult to measure.The source depths in the PDE bulletin,the centroid depths from CMT inversion of USGS and Harvard University,and those obtained by depth phases of broadband waveform data are not equal to each other,and they are also have different meanings.Also,the depth obtained from broadband waveform modeling is another kind of depth of different a rupture "core." This paper preliminarily discusses the physical implication of the source depth of earthquakes with different measuring methods. 相似文献
402.
张家口Ms4.2地震前的地下流体异常 总被引:7,自引:1,他引:6
1997年5月25日张家口MS4.2地震是1997年上半年首都圈地区发生的显地震,虽然该地震震级不高,但地下流体的短临异常十分显。作主要介绍了该地震前地下水流体短临异常的特征高此得到的科学启示 。 相似文献
403.
广西北山岩溶管道—裂隙—孔隙地下水流数值模拟初探 总被引:12,自引:1,他引:11
本文从水动力学角度分析各种岩溶含水介质中的水流特征,将其归纳为储水介质、导水介质和控水介质,并根据折算渗透系数KL的概念和建立耦合达西流和百达西流于一体的岩溶管道-裂隙-孔隙三重介质地下水模型,对广西环江北山矿区岩溶含水系统进行了初步探讨。北山实例的模拟结果表明,三重介质模型较全面地刻画了岩溶水动态的特征,反映了相对均匀裂隙流与控制性管道流并存、线性流与非线性流相互转变的运动特点,不仅理论上比较合 相似文献
404.
CheSalmahMR AbuHassanA AmeiliaZS 《湿地科学》2004,2(1):1-9
Odonata larvae were sampled from 16 tributaries of Kerian River in the Kerian River Basin (KRB) using a kick samphng technique from September 1998 to May 1999 encompassing both rainy and dry seasons. The distribution of odonate genera was significantly different ( F15.16 = 3.99) among rivers in both seasons ( F15.16 = 4.70) at P = 0.05. However, no seasonal influence was detected. Protoneuridae and Libellulidae were the most dominant families in this basin. Other families Gomphidae, Coenagrionidae, Macromiidae, Chlorocyphidae and Calopterygidae, were common but Aeshnidae and Eupheidae were rare. Several common species, Prodasineura autumnalis, Brachythemis contaminata, Macromia gerstaeckeri, Paragomphus, Orthetrum brunneum, Rhinocypha quadrimaculata and Copera marginipes were identified. The calculated values of biological indices ( H‘, D, E, R1 and R2) showed that the dragonfly fauna in this river basin was slightly poor. Varied physieo- chemical parameters of the river possibly as a result of human activities in surrounding areas were found to influence the distribution of the dragonfly larvae in the KRB. This study showed that the KRB provided favorable habitats for Protoneuridae and 1Libellulidae. Two most dominant species Prodasineura autumnalis and Brachythemis contaminata were obviously favoured slightly acidic water of the Kerian river tributaries. 相似文献
405.
Properly fabricated triangular‐plate added damping and stiffness (TADAS) devices can sustain a large number of yield reversals without strength degradation, thereby dissipating a significant amount of earthquake‐induced energy. A pronounced isotropic‐hardening effect is recognized in the force‐deformation relationships of the TADAS devices made from two grades of low yield strength steel. The proposed plasticity‐fibre model employing two surfaces (a yield surface and a bounding surface) in plasticity theory accurately predicts the experimental responses of the TADAS devices. This model is also implemented into a computer program DRAIN2D+ to investigate a frame response with the TADAS devices. Substructure pseudo‐dynamic tests and analytical studies of a two‐storey steel frame constructed with the low yield strength steel, LYP‐100 or LYP‐235 grade, TADAS devices confirm that the dynamic structural response can only be predicted if the proposed plasticity‐fibre model is used for LYP‐100 steel TADAS device. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
406.
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408.
本文介绍了江苏分县逐日滚动1-5天时效的MOS预报的研制,包括降水的概率MOS法和量级MOS法,预报量设置、季节分型和样本选择,因子的构造及其加工,概率统计模型的选择及其因子预选、筛选。最后介绍了MOS工具在省台MICAPS平台上的业务应用及其效果。 相似文献
409.
地下水动态映震机制的试验与观测研究 总被引:3,自引:1,他引:3
本文根据一系列室内外试验与观测研究结果,论述了震前地下水位动态异常信息形成的四个基本环节:①地壳应力活动与含水层应力状态的变化,②含水层变形破坏与孔隙压力的变化;③孔压变化信息在井—含水层系统中的传递;④孔压变化信息在井孔地下水动态中的表现。在此基础上,提出了地下水动态映震特性的若干观点。 相似文献
410.