2-D viscoelastic FEM simulation on stress state in the deep part of a subducted slab     

刘亚静  叶国扬  毛兴华  宁杰远 《地震学报(英文版)》2002,15(3):301-308

Introduction It is found that there are some relationships between the thermal structures of subduction zones and the deep seismicity, while the mechanism relates the thermal structure and the deep seismicity is still unsure (Helffrich, Brodholt, 1991; Furukawa, 1994; Kirby, et al, 1996). From 1980s, geoscientists have constituted a series of numerical simulations on the stress states of subduction slabs. Based on the kinetic computation of Sung and Burns (1976a, b), Goto, et al (1983, 1987…  相似文献   

Study and review on crust-mantle velocity structure in Bohai Bay and its vicinity   总被引：3，自引：0，他引：3  

张成科  张先康  赵金仁  任青芳  张建狮  海燕 《地震学报(英文版)》2002,15(4):447-455

Introduction Bohai Bay, along with its adjacent areas, is one of the seismically active areas in North China. Understanding its crust/upper-mantle structural characteristics and lateral heterogeneity of the medium in this area is of great significance to the study of seismogenic environment, thus improvimg the level of earthquake prediction. For years, scientists have studied the area by gravity and magnetic methods (FENG, et al, 1989), geothermal field (WU, et al, 1988; TIAN, ZHANG, 19…  相似文献   

X线及CT检查在外伤性骨质疏松中的应用及讨论     

黄凯音 《CT理论与应用研究》2002,11(2):32-35

目的 讨论CT及X线检查在外伤性骨质疏松中的应用。方法 1998－2000年200例外伤复查病人行CT及X光检查。结果 2－3个月后出现骨疏松的病人113例，3－4个月后出现骨疏松的66例，未见骨疏松的21例。结论 骨折2－3个月后复查病人，应适量降低CT的窗宽，窗位和X线的照射剂量。  相似文献   

岩石圈流变机制的确定及影响岩石圈流变强度的因素   总被引：20，自引：2，他引：20  

臧绍先  李昶  魏荣强 《地球物理学进展》2002,17(1):50-60

讨论了确定岩石圈流变强度中存在的问题，根据Byerlee定律，给出了在Anderson断层系统下三种断层的摩擦滑动强度公式，利用小标本实验结果外推，用大标本实验结果作约束，得到岩石圈几种典型岩石的脆性破裂规律，利用上述结果和传统的方法，分别得到了鄂尔多斯和山西裂谷两个典型地区的流变强度随深度的变化。结果表明，以往的计算对岩石圈流变强度的估计过高，对脆性形变区估计不足，流变机制估计不对；岩石圈有力学分层的特性，但各地分层的深度范围不同，使得成层和力学作用变得复杂，讨论了水、应变率以及多相矿物对流变强度的影响。  相似文献   

固体介质中弹性波传播机制的细胞自动机有限深势阱模型     

赵雪平  杨宝俊 《地球物理学进展》2002,17(3):390-398

分析了采用细胞自动机研究波动问题的建模方法，针对一维、均匀、各向同性固体介质中弹性纵波的微观机制，借用一经典弹簧振子模型、细胞自动机格子气模型，以及量子力学中的无限深势阱模型，建立了一个细胞自动机有限深势阱模型，从量子力学角度出发，基于介观物理和纳米概念，以微观精子的德布罗意假设为基础，利用薛定谔方程，讨论了该模型中粒子（分子组）的振动速度与粒子物质波波速之间的联系，给出了模型中的波动方程，得出ζ＝Vp（ζ为粒子振动速度，Vp为物质波纵波波速）。同时还讨论了模型中粒子的大小和能量传递问题，引入引力场，得出了能量及引力势的量子化条件，另外，对声波速度、格子气粒子振动速度和本文模型中分子组振动速度进行了比较；还对本文模型中的粒子能量分布作了分析。  相似文献   

A rifted inside corner massif on the Mid-Atlantic Ridge at 5°S     

T. J. Reston  W. Weinrebe  I. Grevemeyer  E. R. Flueh  N. C. Mitchell  L. Kirstein  C. Kopp  H. Kopp  participants of Meteor / 《Earth and Planetary Science Letters》2002,200(3-4):255-269

The structure of the Mid-Atlantic Ridge at 5°S was investigated during a recent cruise with the FS Meteor. A major dextral transform fault (hereafter the 5°S FZ) offsets the ridge left-laterally by 80 km. Just south of the transform and to the west of the median valley, the inside corner (IC – the region bounded by the ridge and the active transform) is marked by a major massif, characterized by a corrugated upper surface. Fossil IC massifs can also be identified further to the west. Unusually, a massif almost as high as the IC massif also characterizes the outside corner (OC) south of the inactive fracture zone and to the east of the median valley. This OC massif has axis-parallel dimensions identical to the IC massif and both are bounded on their sides closest to the spreading axis by abrupt, steep slopes. An axial volcanic ridge is well developed in the median valley both south of the IC/OC massifs and in an abandoned rift valley to the east of the OC massif, but is absent along the new ridge-axis segment between the IC and OC massifs. Wide-angle seismic data show that between the massifs, the crust of the median valley thins markedly towards the FZ. These observations are consistent with the formation of the OC massif by the rifting of an IC core complex and the development of a new spreading centre between the IC and OC massifs. The split IC massif presents an opportunity to study the internal structure of the footwall of a detachment fault, from the corrugated fault surface to deeper beneath the fault, without recourse to drilling. Preliminary dredging recovered gabbros from the scarp slope of the rifted IC massif, and serpentinites and gabbros from the intersection of this scarp with the corrugated surface. This is compatible with a concentration of serpentinites along the detachment surface, even where the massif internally is largely plutonic in nature.  相似文献   

Are hydrous phases more compressible? Implications for high-velocity zones in the deep mantle     

Lin-gun Liu 《Geophysical Journal International》2002,149(1):37-43

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泌阳凹陷安棚油田核三段储层天然裂缝特征研究   总被引：3，自引：2，他引：3  

周文  闫长辉  王洪辉  孙尚如  王志刚 《矿物岩石》2003,23(3):57-60

根据岩芯裂缝观察结果,通过与FMI,MAIN成像测井资料进行对比,系统描述天然裂缝在成像测井上的影像特征,对地层裂缝特征参数进行了确定.成果反映出核三段地层中的裂缝主要为垂直裂缝倾角在80°～90°之间.走向在100°～110°左右,宽度一般小于1 mm,裂缝长度主要在30 mm以内.  相似文献   

锦江水库坝址③号断裂构造破碎带地质特征及其对堤坝安全性的影响     

黄成炽  黄维旺  李志勤 《四川地质学报》2003,23(2):109-111

通过野外地质调查和地球化学探测成果，结合区域地质发展史，论述锦江水库③号断裂构造破碎带的地质特征及其对建筑物的影响。  相似文献   

信阳市燃气混气站断裂活动性和场地稳定性系统研究     

李细光  曾佐勋  彭晓文  董浩斌  程新文 《华东地质学院学报》2003,26(1):18-23

运用多学科、多手段相结合的方法，从区域构造稳定性、构造岩研究、构造裂隙统计分析、红外相位法位移监测，高密度电阻率法、钻探验证、年代学研究、新构造运动分析、遥感图像解译、地震安全性评价、数值模拟、工程地质条件分析等方面入手，对信阳市燃气混气站的断裂活动性和场地稳定性进行了全面而系统的论证；指出场区断裂规模小，第四纪无大规模差异升降运动，无活动断裂通过，邻区地震活动小且弱，区域构造稳定性高，应力平缓，工程地质条件良好，是一个稳定的“岛区”，井指出系统而全面的综合研究方法是研究工程稳定性项目行之有效的手段。  相似文献