克拉通边缘前陆盆地动力层序地层学   总被引：5，自引：1，他引：5  

赵玉光  许效松  刘宝珺 《沉积与特提斯地质》1997,17(1):1-10

通过近几年对层序地层学的深入研究，尤其是对上扬子地台西缘中三叠世拉丁期末和晚三叠世卡尼期周缘前陆盆地层序地层学的研究，提出了动力层序地层学，将边缘前陆盆地由盆缘逆冲断块向克拉通稳定边缘分为Ａ区带和Ｂ区带。  相似文献   

Recovery Behavior of the Propagating Buckle on Elastic Structures     

Liu Zhihong Huang Yuying Liu Qikai Doctor Candidate  Dept. of Mechanics  Huazhong University of Science  Technology 《中国海洋工程》1993,(3)

Based on the beam system model used by Chater, Hutchinson and Neale (1982), the recovery behavior of propagating buckle on elastic structures is first found out from the computational results. As the representative of some elastic structures, the Chater-Hutchinson-Neale model indicates that once the buckle meets arresters, unlike the case in submarine pipelines, it will be reflected back to continue its propagation in a negative phase or a negative direction. The pressure which maintains the negative propagation, however, is as same as that required for the positive propagation. This fact has been examined in the experiment of the bulge propagation on a long elastic latex tube. The present discovery greatly supports the hypothesis that the buckle propagation coresponds to the coexisting phase of structures.  相似文献   

Current Structure and Behavior of the River Plume in Suo-Nada     

Shinya Magome  Atsuhiko Isobe 《Journal of Oceanography》2003,59(6):833-843

The behavior of a river plume in Suo-Nada, Japan, has been studied using a primitive equation numerical model, the Princeton Ocean Model. Special attention has been paid to the current structure and behavior of the anticyclonic eddy (bulge) induced by high freshwater inflow changing on a timescale of one week. First, the freshwater is supplied from a river to a rectangular basin with a simple topography. When the river discharge subsides after reaching its peak value, the bulge propagates upstream (i.e., opposite to the direction of the Kelvin wave propagation). Next, the freshwater is supplied from eight major rivers to the basin with realistic topography. The less saline water mass in the southern part of Suo-Nada propagates to the west (i.e., upstream) after the river discharge subsides. This is consistent with an observed phenomenon, viz., that the less saline water mass appears in the western part of Suo-Nada, suggesting that the upstream propagation of the bulge is possible in the real ocean. Finally, the cause of the upstream propagation is considered. Onshore currents appear in the bottom layer beneath the bulge, propagating upstream. They produce an anticyclonic barotropic eddy due to the conservation of potential vorticity. The current component associated with the eddy crosses normally to the isohaline in the upper layer, and therefore transports the bulge upstream. No other current component (such as surface current velocity minus vertically-averaged value) is responsible for the upstream propagation of the bulge. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

台湾西部前陆盆地和帝汶海前陆盆地的比较学研究     

王海荣  王英民  刘振湖  黄奇志  齐立新 《大地构造与成矿学》2007,31(2):137-144

台湾西部前陆盆地和帝汶海前陆盆地均是新生代环太平洋巨型沟-弧-盆体系的一部分。Huang et al.(2000)认为,帝汶海前陆盆地目前相当于台湾南部陆海域所处的弧-陆碰撞的初始阶段。我们认为,该研究中存在着一种潜在的逻辑上的矛盾。在研究单个前陆盆地时,造山过程和板块的挠曲特性均会成为关注的焦点;而一旦进行盆地之间的对比研究,则往往会倾向于关注造山过程、机制以及构造现象的异同等,并由此得出相应结论,却忽视了在现象异同的背后所隐藏着的板块挠曲特性所起的控制性作用。事实上,帝汶海前陆盆地和台湾西部前陆盆地的根本差异并不在其造山作用和过程,而在于其板块挠曲特性的巨大差异。正是这种差异决定了二者具有完全不同的演化特性,构造、层序上的异同只是这种差异的外在体现。忽视这种差异,仅根据构造上的异同以推断前陆的演化过程会导致认识的偏差。  相似文献   

不对称钢骨混凝土梁抗弯刚度的试验研究   总被引：1，自引：0，他引：1  

陈忠汉  邵永健  朱聘儒  殷志文 《世界地震工程》2001,17(1):103-105

文章在5根不对称钢骨混凝土梁试验研究的基础上，利用现行规范[1]中对称钢骨混凝土梁截面抗弯刚度的计算公式，提出了不对称钢骨混凝土梁截面抗弯刚度的计算方法，建立了相应的计算公式。结果表明，按照本文公式得到的计算值与实测值吻合良好。  相似文献   

Lithosphere,crust and basement ridges across Ganga and Indus basins and seismicity along the Himalayan front,India and Western Fold Belt,Pakistan     

《Journal of Asian Earth Sciences》2013

Spectral analysis of the digital data of the Bouguer anomaly of North India including Ganga basin suggest a four layer model with approximate depths of 140, 38, 16 and 7 km. They apparently represent lithosphere–asthenosphere boundary (LAB), Moho, lower crust, and maximum depth to the basement in foredeeps, respectively. The Airy’s root model of Moho from the topographic data and modeling of Bouguer anomaly constrained from the available seismic information suggest changes in the lithospheric and crustal thicknesses from ∼126–134 and ∼32–35 km under the Central Ganga basin to ∼132 and ∼38 km towards the south and 163 and ∼40 km towards the north, respectively. It has clearly brought out the lithospheric flexure and related crustal bulge under the Ganga basin due to the Himalaya. Airy’s root model and modeling along a profile (SE–NW) across the Indus basin and the Western Fold Belt (WFB), (Sibi Syntaxis, Pakistan) also suggest similar crustal bulge related to lithospheric flexure due to the WFB with crustal thickness of 33 km in the central part and 38 and 56 km towards the SE and the NW, respectively. It has also shown the high density lower crust and Bela ophiolite along the Chamman fault. The two flexures interact along the Western Syntaxis and Hazara seismic zone where several large/great earthquakes including 2005 Kashmir earthquake was reported.The residual Bouguer anomaly maps of the Indus and the Ganga basins have delineated several basement ridges whose interaction with the Himalaya and the WFB, respectively have caused seismic activity including some large/great earthquakes. Some significant ridges across the Indus basin are (i) Delhi–Lahore–Sargodha, (ii) Jaisalmer–Sibi Syntaxis which is highly seismogenic. and (iii) Kachchh–Karachi arc–Kirthar thrust leading to Sibi Syntaxis. Most of the basement ridges of the Ganga basin are oriented NE–SW that are as follows (i) Jaisalmer–Ganganagar and Jodhpur–Chandigarh ridges across the Ganga basin intersect Himalaya in the Kangra reentrant where the great Kangra earthquake of 1905 was located. (ii) The Aravalli Delhi Mobile Belt (ADMB) and its margin faults extend to the Western Himalayan front via Delhi where it interacts with the Delhi–Lahore ridge and further north with the Himalayan front causing seismic activity. (iii) The Shahjahanpur and Faizabad ridges strike the Himalayan front in Central Nepal that do not show any enhanced seismicity which may be due to their being parts of the Bundelkhand craton as simple basement highs. (iv) The west and the east Patna faults are parts of transcontinental lineaments, such as Narmada–Son lineament. (v) The Munghyr–Saharsa ridge is fault controlled and interacts with the Himalayan front in the Eastern Nepal where Bihar–Nepal earthquakes of 1934 has been reported. Some of these faults/lineaments of the Indian continent find reflection in seismogenic lineaments of Himalaya like Everest, Arun, Kanchenjunga lineaments. A set of NW–SE oriented gravity highs along the Himalayan front and the Ganga and the Indus basins represents the folding of the basement due to compression as anticlines caused by collision of the Indian and the Asian plates. This study has also delineated several depressions like Saharanpur, Patna, and Purnia depressions.  相似文献   

Blending in gravitational microlensing experiments: source confusion and related systematics     

Martin C. Smith  Przemys&#;aw Wo&#;niak  Shude Mao  Takahiro Sumi 《Monthly notices of the Royal Astronomical Society》2007,380(2):805-818

  相似文献   

琼东南盆地深水区岩石圈伸展模式及其对裂后期沉降的控制   总被引：5，自引：1，他引：4  

佟殿君  任建业  雷超  阳怀忠  尹新义 《地球科学》2009,34(6):963-974

为了揭示盆地深水区演化及裂后期大规模沉降的成因机制, 在琼东南盆地典型的、高品质地震剖面地质构造精细解释基础上, 结合岩石圈变形的挠曲悬臂梁模型和挠曲均衡模型, 应用正演和反演模拟技术, 定量恢复了该盆地所处地区的上地壳、地壳以及岩石圈的伸展程度.结果表明, 琼东南盆地自陆架边缘到深水坳陷区, 岩石圈上地壳的伸展系数较小, β值最大为1.23~1.32;整个地壳的伸展系数变化较大, 盆地边缘隆起区的β值在1.1~1.2之间, 向盆地中部β值逐渐增大到3.14;而对整个岩石圈而言, 其伸展系数β值由陆架到陆坡深水盆地也从1.2逐渐增大到4.2.根据对南海地区的构造及岩石圈和地壳的结构分析认为, 与McKenzie的岩石圈均一伸展以及由热控制的裂后期缓慢沉降过程不同的是, 上述与深度相关的岩石圈伸展减薄是由南海西北次海盆扩张过程中深部物质的离散上涌流动所导致的下地壳的快速而强烈的塑性流动所引起的, 并由此建立了琼东南盆地的形成演化模式, 来解释和探讨深水坳陷区及裂后期快速而大规模沉降的成因机制.   相似文献   

反复荷载作用下锈蚀钢筋混凝土压弯构件恢复力性能的试验研究   总被引：24，自引：0，他引：24  

史庆轩  牛荻涛  颜桂云 《地震工程与工程振动》2000,20(4):44-50

采用外加电流对混凝土压弯构件中的钢筋进行了快速锈蚀试验,通过钢筋锈蚀混土压弯构件在水平反复荷载作用下的试验研究,探讨了钢筋锈蚀程度对混凝土压弯构件的承载力,刚度,延性,耗能能力等的影响,给出了锈蚀构件的滞回曲线和骨架曲线。  相似文献   

Estimation of base motion in instrumented steel buildings using output‐only system identification          下载免费PDF全文

Dimitrios G. Lignos  Eduardo Miranda 《地震工程与结构动力学》2014,43(4):547-563

A procedure to estimate the seismic motion at the base of a building from measured acceleration response at two or more floors is presented. The proposed method is comprised of two steps. In the first step, the dynamic characteristics of the building are inferred by using an output‐only system identification procedure. In the second step, the motion of the base of the building is estimated by using the transfer function of a simplified building model consisting of a shear and flexural continuous beam together with dynamic properties obtained in the first step. The proposed method is validated first with an analytical model subjected to the 1940 El Centro ground motion and then with an instrumented building in California that experienced the 1994 Northridge earthquake, and the ground motions at the base of the building are available. It is shown that the proposed method is capable of providing very good estimates of the motion at the base. The use of the proposed method is finally illustrated on an instrumented building, where the sensor at the base of the building did not function during the 1994 Northridge earthquake. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献