地震折射波法探测研究张强地区的构造特征     

孟补在  朱兆言 《东北地震研究》1998,14(1):71-75

张强地区位于中朝地台北缘的吉黑地槽区,其基底岩系和构造特征与中朝地台的基底和构造特征有明显的差别,通过２００ｋｍ的折射波法探测,得出如下结论：（１）本区基底构造线方向呈现近ＳＮ或ＮＮＷ向,二条此方向的断层划分出三个构造单元。（２）该区内中生代前基底分为两套地层,其岩性、断层特征和基底埋深均有差别。  相似文献   

一种利用贝叶斯最小判别准则估计未来地震危险的新方法   总被引：2，自引：0，他引：2  

金学申  邵辉成 《中国地震》1998,14(3):88-93

提出了一种基于最大似然和贝叶斯最小判别准则的新预测方法,它的长处在于对样本数无特殊要求,所以,对低地震活动地区,此模型也能得到与时间有关的稳定的未来强震危险估计。最后,以华北地区为例,说明了本方法的可行性。  相似文献   

某古岩溶铀矿床中铀,钼,铼的赋存状态     

吴俊奇  闵茂中 《矿物学报》1998,18(3):325-330

本文采用电子探针、透射电镜和化学物相法,查明某古岩溶铀矿床中铀主要呈显微和超显微状沥青铀矿、铀石,其次呈分散吸附状和铀酰（次生）矿物形态存在;钼主要呈蓝钼矿、钼钙矿、钼华、钼铅矿等氧化物,其次呈胶硫钼矿等形态存在;铼主要呈吸附状,其次可能在黄铁矿中呈二硫化物包裹体形态产出。最后讨论了该三个元素赋存状态与该铀矿床形成地球化学环境之间的关系。  相似文献   

藕塘古滑体在三峡水库形成后的稳定性分析   总被引：2，自引：0，他引：2  

杨家岭  朱维申  罗晓东  张玉军 《岩土力学》1998,(2)

采用极限平衡和三维弹塑性有限元分析方法,对藕塘古滑体在三峡水库形成后的稳定性进行了计算分析。计算中考虑了水库水位变化、渗透压力、建筑荷载以及地震等诸多因素对滑体稳定性的影响,并给出了滑体失稳的临界破坏条件,为库区移民迁建新址的勘察工作提供了量化的论证。  相似文献   

随机介质理论在深基坑稳定性分析中的应用   总被引：9，自引：1，他引：8  

朱文彬  张家生 《岩土力学》1998,19(2):14-18

使用矿业工程中广为应用的随机介质理论和方法,计算深基坑开挖引起的地表及土体变形,并据此探讨深基坑边坡的稳定性。  相似文献   

核地球物理和化探综合测量在上海市区工程地质调查中的应用     

朱炳球  张学仁  杜广通  余慧 《物探与化探》1998,(1)

本文介绍在上海市区断裂构造调查中 ,核地球物理测量和化探的应用效果。应用α卡、地面伽马能谱U、Th、K和总量 (Σ)及壤中气汞等测量方法 ,采用组合指标推断断裂构造 ,推断出的断裂构造与地震推断的结果相比较 ,具有较好的一致性。这些方法经济、快速、有效 ,有着广泛的应用前景  相似文献   

Silicon Isotope Geochemistry of Micro—Fine Disseminated Gold Deposits in SW Guizhou and NW Guangxi,China     

刘显凡  倪师军等 《中国地球化学学报》1998,17(3):249-257

Quartz was studied with respect to its silicon isotopic composition and cathodoluminescence in micro-fine disseminated gold deposits in SW Guizhou and NW Guangxi.The results showed that quartz in wall rocks.ores and that in association with hydrothermal silicification are distinctive in silicon isotopes and cathodoluminescence characters.Quartz in association with primary silicification is non-luminescent while that in wall rocks and associated with secondary silicification exhibits striking luminescence.Based on the dynamic fractionation of silicon isotopes,it is suggested that the mineralization was accompanied by rapid transport of aprimary siliceous fluid along the major deep fault system into subordinate faults before ore components deposited in favorable strata via penetration and metasomatism.Therefore,a deep origin is implicit for gold deposits of this type.  相似文献   

Preliminary results of measuring the crustal deformation in Qinghai-Xizang area using GPS technique   总被引：5，自引：0，他引：5  

Zhu Wenyao  Cheng Zongyi  Xiong Yongqing  Xu Huaguan 《中国科学D辑(英文版)》1998,41(3):314-318

GPS repetition measurement tbta in Qinghai-Xizatlg (Tibetan) area in 1992 and 1994 have been used to determine the change rates of seven bascline vectors of Lhasa-Wenquan, etc. It is the first time to obtain the direct observation results of the large-scale crustal horizontal motions in this area. Thesc preliminary results also for the first time provide the direct observation evidence for some important geophysical and geological viewpoints, such as the northward gradual reduce of the effect of the northward push-pressing to Eurasian continent by Indian Plate in the Qinghai-Xizang area, having a southward strike slip movement of the Chuan-Dian diamond block, etc.  相似文献   

Estimating open boundary conditions from coastal tidal observations by adjoint approach     

Zhu Jiang  Zeng Qincun  Guo Dongjian  Liu Zhuo 《中国科学D辑(英文版)》1998,41(3):330-336

A numerical study for estimating the tidal open boundary conditions of a shelf current modrl from tb coastal tidal observations is presented. The method is based on the optimal control/adjoint method. A lrast square fitting of the model state to simulated data is used. Two ideal domains and coastlines are considered. Using the IAP shallow. water model and its adjoint model, some identical twin experiments are carried out to test efficiency and lirnilsd of the method. The results show that the adjoint method can efficiently estimate the open boundary conditions well for gulf/bay like domains. The adjoint method seems to have great potential to improve the accuracy of tide and shelf current modeling in coastal regions. Project supported hy the National Natural Science Fuundation of China (Grant No. 49376256)  相似文献   

Processes of the deposition and vicissitude of Mu Us Desert, China since 150 ka B.P.   总被引：1，自引：0，他引：1  

Li Baosheng  Jin Heling  Lü Haiyan  Zhu Yizhi  Dong Guangrong  Sun Donghuai  Zhang Jiashen  Gao Quanzhou  Yan Mancun 《中国科学D辑(英文版)》1998,41(3):248-254

“Milanggouwan stratigraphical section” named lately takes down 27 cycles of alternately evolutionary histories of desert depositions in the Mu Us area with the fluviolacustrine facies and palaeosols since 150 ka B. P. Studies show that the sedimentary form was induced by the growth and decline and confrontation each other between the winter monsoon and the summer monsoon of East Asia in the past 150 ka. Project supported by the National Natural Science Foundation of China (Grant No. 49473192).  相似文献