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1.
No. 1,2008 Transition from wavelets to ripples in a laboratory flume with a diverging channel William B. RAUEN,Binliang LIN,and Roger A. FALCONER (pp. 1–12) Impact of water diversion on the morphological development of the lower Yellow River Zheng Bing W…  相似文献   

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《国际泥沙研究》2007,22(4):327-328
No. 1, 2007 Prediction of the Grain Size of Suspended Sediment: Implications for Calculating Suspended Sediment Concentrations Using Single Frequency Acoustic Backscatter R. A. KUHNLE, D. G. WREN, and J. P. CHAMBERS (pp. 1-15) Numerical Modeling of Heavy Metal Pollutant Transport-Transformation in Fluvial Rivers:A Review S. L. HUANG, Z. H. WAN, and P. SMITH (pp. 16-26) Sediment Transport Capacity-An Improved Bagnold Formula Shu-Qing YANG, Sung-Cheol KOH, In-So…  相似文献   

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· Reporton An Investigation·Macroscopical Seismic Intensity Survey Report for 2 0 0 2 Haozhuang,Taiyuan Earthquake of ML5.0……………………………………………………CHENG Xin- yuan,DING Xue- wen,ZHANG Da- wei  4  (1 )………………………………………………  相似文献   

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Sedimentation processes in reservoirs can be studied by performing theoretical analysis, laboratory experimentation, numerical simulation, or a combination of these three methods. Available literature focused on reservoirs is abundant. For instance, the works conducted by Hotchkiss and Parker (1991), Morris and Fan (1997), and De Cesare et al.  相似文献   

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This discussion will address two aspects found in the paper:lack of proper information and some mistakes. Lack of proper information In Section 2 of the paper,a short review of the seismic events suffered by the Basilica and of the interventions of reconstruction which have followcd is presented,but the main effects of these events are not sufficiently highlightcd.In what follows,additional information is provided to allow a better understanding of the most recent retrofit intervention and of the seismic behavior of the Basilica in 2009.  相似文献   

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Developing an accurate chronological framework is always a key issue in paleoclimatic studies. Magneto- stratigraphy has been a routine tool for such purposes. However, complexities arise for inter-profile correla- tions of magnetostratigraphy due to effects of the lock-in process. One good example is the “mystery” of the mismatching of stratigraphic locations of the Matuyama/Brunhes boundary (MBB) (occurred at ~780 ka) recorded in Chinese loess and marine sedi- ments. Tauxe et al.[1] con…  相似文献   

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1 FLOW INTENSITY, PF Local scour processes differ between clear-water (sub-threshold) and live-bed (post-threshold) conditions of sediment transport on the channel bed ahead of the bridge abutment. As described by Melville and Coleman (2000), the stage of sediment transport can be represented by the mean velocity ratio U/Uc, termed the flow intensity. For U/Uc 1, clear-water conditions pertain, while live-bed scour occurs for U/Uc > 1. The variation of local scour depth at bridge …  相似文献   

8.
1 INTERNAL HYDRAULIC JUMPS AND LOCAL WATER ENTRAINMENT Traveling and stationary internal hydraulic jumps in two-layer flow can occur in the following situations (Fig. 1). When a stratified fluid flows over an obstacle created by a sudden blockage, the layer of increased depth within the heavier fluid will propagate upstream as a traveling hydraulic jump. When the heavier fluid overtops the obstacle it will flow along the downstream face of the obstacle as a supercritical flow…  相似文献   

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A two-dimensional mathematical model for simulating flow and sediment transport is presented. The model simulates flow and geo-morphological processes using a high order accurate, oscillation free scheme. The depth averaged Reynolds (shallow water) equations are used for flow simulation. Both equilibrium and non-equilibrium methods (by solving convection-diffusion equation) are used for sediment transport modeling while sediment carrying capacity is computed using different methods. A finite volume, flux difference splitting scheme is employed to solve the governing equations, which is able to simulate sub, super and transeritical flows with shock waves. Moreover, the numerical method is able to simulate flow over the variable topographies and it has a low level of numerical diffusion in the case of circulating flows like headlands. The computational grid of this model is triangular unstructured with variable size, which is flexible for arbitrary geometries and grid refinement. Using the model for simulating flow and sediment transport in some test cases such as a partially closed channel and comparing the results showed that the results obtained by the developed model were in a reasonable agreement with measurements and the other models cited.  相似文献   

11.
The Qianguo M_S5. 8 earthquake swarm of 2013 occurred in Qianguo,Jilin Province,China. There are five earthquakes with M_S≥5. 0 in the Qianguo earthquake swarm,with magnitudes of M_S5. 5,M_S5. 0,M_S5. 3,M_S5. 8 and M_S5. 0. In this study,the far-field seismic radiated energy characteristics of the earthquakes are compared based on the source spectrum and the ground motion spectrum of the earthquake swarm. The ground motion spectrum of the five earthquakes at Changchun seismic station( CN2),which is the national standard station,is first investigated with the recorded ground motions,and then the far-field seismic radiated energy is calculated and combined with the relationships of the source spectrum to describe the variable characteristics of the Qianguo earthquake swarm. Research results indicate that the second earthquake( No. 2) with M_S5. 0 is the key event of the earthquake swarm,which occurred on October 31,the same day following the first M_S5. 5 earthquake( No.1). In fact,the magnitude of event No. 2 decreased compared to event No.1,which did not agree with its large far-field seismic radiated energy. It needs to be pointed out that event No. 2 was the turning point event of the Qianguo earthquake swarm,as being a significant transition before the largest M_S5. 8 earthquake.  相似文献   

12.
<正>The author,Prof Subhasish Dey,presents an up-to-date and comprehensive consideration of hydrodynamic principles to analyze sediment transport phenomenon.The author is well known in the field of applied hydrodynamics and sediment transport,with wide experience in theoretical and applied research.The book is intended for postgraduate and research students,who already have a decent knowledge and understanding of fluid mechanics,as well as for model developers and users of theoretical models in the fluvial hydrodynamics field.The author's intention is to introduce the readers to the mechanics and physics of sediment transport by turbulent flow,  相似文献   

13.
On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earth- quake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7~7 41 and an intensity of about IX~X. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event [before (83±46) B.C.] obtained by the trench investigation. Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M 7~7 4/1 Wudu earthquake in 186 B.C. should be in the middle-east segment of Diebu-Bailongjiang active fault zone.  相似文献   

14.
The main characteristic of the East Asian climate is the monsoon system. Plenty of studies have demonstrated that the Asian monsoon system plays a crucial role in the global climate sys- tem [1-4]. The Asian summer monsoon can be divided into two parts, t…  相似文献   

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The statistical mechanics of earthquakes adopts the concepts and methodology of statistical mechanics, especially the theory of critical phenomena, in studying the preparation, initiation, propagation and healing of earthquake rupture, which forms a new branch in the physics of seismic source in recent years. This article introduces to the fundamental concepts of the statistical mechanics of earthquakes. The introduction includes the seismic Hamiltonian, percolation model, earthquake rupture nucleation, and Burridge-Knopoff spring-block model. It is pointed out that some of the statistical mechanical models of earthquakes have a sound seismological basis. There is a smooth "transition" from the "classical" theory to the "modern" theory of seismic source.  相似文献   

17.
An earthquake is regarded as a fracture from the viewpoint of continuum mechanics, in which stress and strain play key roles in understanding the nature of a seismic source. This review briefly outlines the mechanics of a seismic source in terms of the dislocation model and crack model. The introduction includes the Coulomb failure criterion, static stress drop, dynamic stress drop, the Griffith criterion, and the scaling of source parameters. The selection of topics in the introduction emphasizes the application of seismic data, i.e., in practice, the mechanical parameters introduced here are measurable in the interpretation and analysis of seismic waveform data.  相似文献   

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Xu Jie 《中国地震研究》2006,20(1):101-107
The Indonesian region is one of the most seismically active zones on the earth. On December 26, 2004, an Ms 8.7 earthquake (as measured by the China Seismograph Network, or Mw = 9.3 as measured by USGS) struck the west coast of northern Sumatra, Indonesia. By its magnitude it is classified as the world's fourth largest earthquake since 1900 and the largest one since the 1964 Alaska earthquake. The spatial distribution of the relocation of larger aftershocks ( M 〉 4.5) following the main shock suggests a length and width of the rupture of about 1200km and 200km, respectively. The shock triggered massive tsunamis that affected several countries throughout South and Southeast Asia. It is a shallow interplate event of thrust type in the trench. Its epicenter is located at the northwestern end of the Indonesia-Melanesia plate boundary tectonic zone. In 2004, eight shocks of M≥ 7.0 occurred in this area, showing a migration from east to west. It implies that these shocks represent a correlated and consistent dynamic process along this subduction zone. These interplate events are associated with convergence of several plates and their fast motion in this region, which result in strong and complex structures and deformation. The India-Australia plate is underthrusting toward the Sunda continental block or Burma plate at a low angle, producing a great locked area on the shallow portion of the subduction zone where enormous strain is accumulated. Interseismic uplift recorded by coral growth and horizontal velocities measured by GPS show the geometry of the locked portion of the Sumatra subduction zone. The vertical and horizontal data reasonably match with a model in which the plate interface is fully locked over a significant width. This locked fault zone extends to a horizontal distance of 132km from the trench, which corresponds to a depth of 50km. The sudden ruptures and large-scale slip of this locked area as a release of stress occurred, are the direct cause of the M8.7 earthquake near Indonesia in 2004.  相似文献   

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