排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
根据中朝地台东北缘地区 (东经 1 1 7°0 0′— 1 2 6°0 0′ ,北纬 36°0 0′— 44°0 0′) 1 980— 1 997年的 380 0 0余条P波走时数据 ,利用正交投影法重建了该区地壳和上地幔的三维速度结构 .通过分析及同人工地震测深剖面的详细对比 ,证明了成像结果的可靠性 .结果表明 :中朝地台东北缘地区地壳上地幔介质存在显著的横向不均匀性 ,直至 1 2 0km深度处依然明显 ;地壳上部的速度图像清楚地反映了不同岩石单元的分布与该区不同性质的基岩分布基本吻合 ;从上、中地壳的速度图像中发现了研究区存在海城、朝阳、义县、丹东南、唐山等几个低速异常区(即速度逆反层区 ) ,其中海城、唐山、朝阳等地区的壳内低速层已由深地震测深资料所证实 ;研究区陆地发生的几次强震均发生于壳内低速层上方的高速脆性介质内 ,而渤海发生的强震 ,此现象不明显 ,但都发生于横向介质速度显著突变的位置 ;在地壳不同深度上发现了普兰店至山海关横跨渤海的北西向低速异常带 ;地震层析二维速度图像与深地震测深资料的对比表明 ,研究区利用地震层析成像技术 ,在一定条件下可以获得与人工地震测深相似的效果 相似文献
2.
以东北地区的地学断面及其相关资料为基础,分析了郯庐断裂北带地区的地壳-上地幔结构特征与不同地壳构造单元地震活动性之间的关系.结果表明:郯庐断裂北带两侧的壳幔结构存在明显差异,断裂带本身的发育与壳幔结构变异带关系密切;断裂的活动特点及分段明显受到地壳介质力学特性影响;郯庐断裂北带地区软流层的起伏与地貌形态呈明显的镜像关系,前者还制约着不同地壳构造单元的构造活动性及变形方式;郯庐断裂北带地区南、北两端地震较为活跃地段均与壳内低速 高导层发育地段相对应的事实,证明了刚性地块中壳幔结构较为复杂的活动断裂段是构成中强地震的主要控震构造. 相似文献
3.
吉林深震群位于中国东北大陆板缘古生代地槽褶皱系内,上叠有中新生代断陷裂谷盆地。区内广泛喷溢了βN_2—βQ_4玄武岩浆,深震震中大多位于火山口、火山锥玄武岩内附近。从岩浆幔漂包体、岩浆岩化、岩浆携带的上地幔岩石组合出现顺序的综合判断,上地幔可分出Ⅷ层序以及推断的深震源Ⅸ层序列,据平剖面分析深震与玄武岩浆共生活动。日本海沟—我国深震区中深源地震震源机制解表明P轴呈连续地插入我国东北上地幔深度590km层内并持续活动,深震发生的动力来自西太平洋岩石圈板块俯冲消减运动本身的挤压应力活动。 相似文献
4.
5.
本文叙述了闾阳-康平-长春地学断面计算机数字化管理管理系统的设计思想、功能特点及实现过程,该系统的管理模式有利于对矿产资源、地震灾害的预测和预报。 相似文献
6.
7.
介绍了在AutoCAD环境下闪烁显示地质条带上相同属性符号及区域轮廓的设计方法,为CAD开发应用提供了一个动态显示功能。 相似文献
8.
9.
Based on 38?000 P wave arrival times recorded during the period of 1980 to 1997 in the northeast margin area of Sino Korean platform (117°00′\126°00′E, 36°00′\44°00′N) the 3D velocity structures of the crust and upper mantle have been reconstructed by using orthogonal projection. The tomography results have been proved to be reliable by analyzing and comparing in detail the results with the deep seismic prospecting profiles. It is shown that there exists obvious lateral inhomogeneity in the medium of the crust and upper mantle which is still distinct even at the 120km depth in the northeast margin area of Sino Korean platform. It is reflected clearly in the velocity image of the upper crust that the distribution of all kinds of rock elements corresponds to that of rocks with different nature in this area. Several lower velocity anomaly regions (i.e. regions with velocity reversed layer) have been discovered in the studied area from the velocity images of upper and middle crust, such as Haicheng, Chaoyang?Yixian, south of Dandong, Tangshan etc., among which the lower velocity layers in Haicheng, Tangshan, Chaoyang have also been proved by the deep seismic sounding data. In the area several strong continental earthquakes all happened in crispy medium with higher velocity above lower velocity layers in the crust, whereas in Bohai sea all strong earthquakes happened in positions where the medium velocity changes abruptly and clearly in horizontal. At different depth, Pulandian Shanhaiguan lower velocity anomaly zone across Bohai sea with strike NW has been found. Comparison of the velocity images obtained from 2D seismic tomography with that from deep seismic sounding data, we can consider to gain similar effect with deep seismic sounding by taking advantage of seismic tomography under certain condition in this area. 相似文献
10.
IntroductionThe Northern Tanlu fault zone (from Yingkou to Luobei) crosses the northeast mainland ofChina. Because of its large scale, long history activity and controlling earthquakes prominently, itis paid closely attention by geologists, and a imp amount of geological survey has been done inthese years (Bureau of Geology and Mineral Resources of Liaoning Province, 1989; Bureau ofGeology and Mineral Resources of Jinn Province, 1988; Bureau of Geology and Mineral Resources of Heilongi… 相似文献