Complex　time－space　spreading　and　focal　mechanism　of　the　1989　Batang　earthquake　swarm　（M_s＝6．7）   总被引：1，自引：0，他引：1  

程万正  陈天长 《地震学报(英文版)》1994,(2)

Ｃｏｍｐｌｅｘ　ｔｉｍｅ－ｓｐａｃｅ　ｓｐｒｅａｄｉｎｇ　ａｎｄ　ｆｏｃａｌ　ｍｅｃｈａｎｉｓｍ　ｏｆ　ｔｈｅ　１９８９　Ｂａｔａｎｇ　ｅａｒｔｈｑｕａｋｅ　ｓｗａｒｍ　（Ｍ＿ｓ＝６．７）（程万正）（陈天长）Ｃｏｍｐｌｅｘｔｉｍｅ－ｓｐａｃｅｓｐｒｅ...  相似文献   

环太平洋地震带与柯里奥利力   总被引：5，自引：0，他引：5       下载免费PDF全文

杨学祥  朮洪亮 《地震工程学报》1995,17(4):13-16

柯里奥利力是地球自转的一种惯性力，它使垂直下降的物体向东偏转，垂直上升的物体向西偏转，是形成环太平洋地震带中东西两岸构造应力差别的根本原因。  相似文献   

Microseismicity of the ultraslow-spreading Gakkel ridge, Arctic Ocean: a pilot study     

Vera Schlindwein  Christian Müller  Wilfried Jokat 《Geophysical Journal International》2007,169(1):100-112

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青藏高原的隆升：青藏高原的岩石圈结构和构造地貌   总被引：20，自引：1，他引：20       下载免费PDF全文

崔军文  李朋武等 《地质论评》2001,47(2):157-163

笔者回顾青藏高原隆升研究的历史，剖析各种隆升动力学模式，依据着青藏高原岩石圈组成的构的强烈不均一性和、三分性”，“对称性”构造地貌格局，提出了青藏高原隆升是印度地块和塔里木一可拉善地块双向不均一俯冲和青藏腹地深层热隆扩展联合作用的结果，俯冲是高原隆升的重要机制，而热隆扩展是高原隆升的直接原因。  相似文献   

Stochastic sketching of infiltration-advance isochrones     

W. O. Rasmussen 《Stochastic Environmental Research and Risk Assessment (SERRA)》1996,10(3):209-229

A technique has been developed for predicting the irregular advance pattern often observed as water spreads on the surface of the ground. The technique is a combination of stochastic sketching, potential theory, probability theory, and a mass balance equation in the form of an advance equation. The technique can be used on flat as well as sloping terrain and addresses any form of obstructions or constraints to the flow of the water. The stochastic sketching portion of the technique uses cellular automata with transition probability movement rules to sketch the dynamics of small volume water elements in the defined environment. Randomly selected small volume flow path segments are computed and plotted. The envelope of these segments defines the wetted area and the advance front. Several examples are presented showing the patterns produced for various situations.  相似文献   

Anomalous structural evolution of the Shimanto Accretionary Prism at Murotomisaki, Shikoku Island, Japan     

James  Hibbard  Daniel  Karig Asahiko  Taira 《Island Arc》1992,1(1):133-147

Abstract The Late Oligocene-Early Miocene Nabae Sub-belt of the Shimanto Accretionary Prism was created coevally (ca 25-15 Ma) with the opening of the Shikoku back-arc basin, located to the south of the southwest Japan convergent margin. The detailed geology of the sub-belt has been controversial and the interaction of the Shimanto accretionary prism and the opening of the Shikoku Basin has been ambiguous. New structural analysis of the sub-belt has led to a new perception of its structural framework and has significant bearing on the interpretation of the Neogene tectonics of southwest Japan. The sub-belt is divided into three units: the Nabae Complex; the Shijujiyama Formation; and the Maruyama Intrusive Suite. The Nabae Complex comprises coherent units and mélange, all of which show polyphase deformation. The first phase of deformation appears to have involved landward vergent thrusting of coherent units over the mélange terrane. The second phase of deformation involved continued landward vergent shortening. The Shijujiyama Formation, composed mainly of mafic volcanics and massive sandstone, is interpreted as a slope basin deposited upon the Nabae Complex during the second phase of deformation. The youngest deformational pulse involved regional flexing and accompanying pervasive faulting. During this event, mafic rocks of the Maruyama Intrusive Suite intruded the sub-belt. Fossil evidence in the Nabae Complex and radiometric dates on the intrusive rocks indicate that this tectonic scheme was imprinted upon the sub-belt between ～23 and ～14 Ma. The timing of accretion and deformation of the sub-belt coincides with the opening of the Shikoku Basin; hence, subduction and spreading operated simultaneously. Accretion of the Nabae Sub-belt was anomalous, involving landward vergent thrusting, magmatism in newly accreted strata and regional flexing. It is proposed that this complex and anomalous structural history is largely related to the subduction of the active Shikoku Basin spreading ridge and associated seamounts.  相似文献   

New radiolarian ages from the Troodos ophiolite and their tectonic implications   总被引：3，自引：0，他引：3  

Soichi  Osozawa Makoto  Okamura 《Island Arc》1993,2(1):1-6

Abstract Newly obtained radiolarian biostratigraphic age combined with previous isotopic age of the Troodos ophiolite shows that the ophiolite becomes systematically younger from east to west: Turonian, early Campanian, and late Campanian. The youngest late Campanian part of the ophiolite is directly covered by the volcaniclastic sediment derived from an active island arc, whereas the older part is covered by pelagic radiolarite. These facts constitute evidence that the Troodos ophiolite was probably emplaced during the subduction of an active spreading ridge.  相似文献   

冲绳海槽宫古段中央地堑的形态与分布   总被引：3，自引：0，他引：3  

栾锡武  高金耀  梁瑞才  秦蕴珊 《地质学报》2006,80(8):1149-1156

采用中国科学院海洋研究所“科学1号”调查船及国家海洋局“向阳红9号”调查船最近几年在冲绳海槽宫古段进行海底地形及反射地震调查所取得的数据,首次详细展示了冲绳海槽宫古段南北长约200km区域内中央地堑的形态及空间展布特征。本文给出的成果大大加深了关于冲绳海槽中央地堑各种变化的认识。指出,按照形态,中央地堑分为U型、V型和半地堑三种。其中大部分中央地堑为U型地堑。地堑的深度40～250m,宽度6～14km,长度17～33km。冲绳海槽宫古段的最大水深为2244.4m,位于中央地堑城阳段北端底部靠东的一侧(125°19.3′E,25°49.8′N)。本研究区的中央地堑可分为断续的9段,从东北向西南大致呈右旋雁行排列。但黄岛段相对于崂山段,城阳段相对于莱西段,李仓段相对于城阳段又稍微向西偏出,呈现为左旋雁行排列。地堑的走向一般为N60°E左右,相对于冲绳海槽的走向更偏向于东西方向,偏角在15°左右。各段中央地堑是被NW向断裂错开的。这些断裂在海底表现为明显的海底断崖地貌和陡沟地貌,在地震剖面上表现为明显的地层错位,其错位的幅度往往老地层比新地层要大。根据地震剖面分析,这些NW向的断裂应该是走滑性质的。本文展示的中央地堑在形态上和空间展布形式上都和扩张洋脊类似。莱西段和城阳段中央地堑之间重叠地堑,在形式上也类似于扩张洋脊的重叠扩张中心。从地堑深度较浅并发育重叠地堑来分析,冲绳海槽的扩张速率应当介于慢速扩张和中速扩张之间。本研究区莱西段、即墨段和平度段海底地形相对较高,中央地堑深度变浅,并发育重叠中央地堑,应该相当于快速扩张大洋中脊的轴高,可能是正在孕育岩浆活动的位置。目前我们所观测到的中央地堑的错断和有规律的排列说明海槽的主体演化过程已经在拉张盆地和断陷盆地的基础上上升到一个更高的阶段。本文根据中央地堑的展布形式、重叠中央地堑,及其两侧中央地堑中的海底山推测此区域海底扩张可能正在进行。  相似文献   

地震研究新方法——洋壳流理论简介   总被引：1，自引：0，他引：1  

赵大咏  刘石年  吴奇良 《华南地震》2007,27(2):62-68

根据交换平衡力学原理[1],简要地介绍了洋壳流的概念及其运动特点。根据运行区域和方向的不同,把三大洋的海底扩张运动划分为不同的洋壳流,并绘出运行路线图。提出洋壳流运动方向、路线及力作用大小的判断方法,通过不同区域洋壳流相互力作用的对比,分析海底扩张运动对地震时空分布及变化规律的影响。  相似文献   

近岸水平场地液化侧向大变形影响因素分析   总被引：2，自引：0，他引：2  

蔡晓光  袁晓铭  刘汉龙  孙锐 《世界地震工程》2007,23(2):20-25

利用改进的软化模量分析方法,对近岸水平场地液化侧向大变形进行数值计算,以研究地震波波形和幅值大小、液化、竖向地震动对侧向大变形的影响。结果表明:不同的地震波作用下,即使峰值加速度相同,液化程度与侧移距离也可能有较大不同,表现了土体变形的强非线性性质,但大地震下液化导致的侧移几乎都在米的量级上;计算区域中无液化区时,岸壁侧向永久位移很小,在几公分左右,随水平峰值加速度及不同地震动输入改变不大;计算区域中有液化区时,岸壁侧向永久位移显著增大,且随输入水平峰值加速度的增大而明显增大,其机理是强地震动使液化范围加大;水平竖向两向地震动输入与单独水平地震动输入相比,前者场地液化范围增大,平均增大42%,侧移量增加,平均增加37%。  相似文献