延边地层区晚石炭世地层     

苏养正 《吉林地质》1996,(Z1)

本文提出延边地层区的晚石炭世地层有两种类型：一是原地系统的天宝山组；二是外来岩块，包括原山秀岭组。并建议停止使用山秀岭组一名。  相似文献   

The transition from passive to active margin tectonics: a case study from the zone of Samedan (eastern Switzerland)     

M. R. Handy 《International Journal of Earth Sciences》1996,85(4):832-851

The Zone of Samedan is part of a fossil, early Mesozoic rift system originally situated in the distal, Lower Austro-Alpine domain of the Adriatic passive continental margin. An early Mesozoic configuration of asymmetrical rift basins bounded by relative structural highs compartmentalized Late Cretaceous active margin tectonics; Jurassic half-grabens were folded into arcuate synclines, whereas relative structural highs engendered thin, imbricated thrust sheets. West-directed thrusting and folding initiated at the surface and continued to depths favoring mylonitization under lower greenschist-facies conditions. At this time Liguria-Piemontese ophiolites were accreted to Lower Austro-Alpine units directly underlying the Zone of Samedan. Late Cretaceous orogenic collapse of the Adriatic active margin involved the reactivation of west-directed thrusts as low-angle, top-to-the-east, normal faults. These faults accommodated extensional uplift of Liguria-Piemontese ophiolites and Lower Austro-Alpine units beneath and within the Zone of Samedan. During Paleogene collision, some Late Cretaceous faults in the Zone of Samedan were reactivated under lower anchizonal conditions as north-directed thrusts. The latter stages of this early Tertiary thickening were transitional to brittle, high-angle normal faulting associated with top-to-the-east extension and spreading above the warm, uplifting Lepontine dome.  相似文献   

三维分块倾斜界面的反演及其应用   总被引：3，自引：0，他引：3       下载免费PDF全文

赖晓玲  郑需要  张先康 《地震工程学报》1997,19(3):63-68

介绍了利用反射波走时反演介质层速度和包含直立断层的三维界面的计算方法．对各层界面利用多个倾斜或平界面方程来描述．给出了数值计算实例．结果表明，反演解与真模型很接近，说明计算方法是有效的．利用该方法处理了唐山地震区的ＰｍＰ反射波资料，获得了该区域莫霍界面的三维分块形态．唐山附近莫霍界面错断与该区域１９７６年唐山地震及一系列余震的发生有密切的联系．  相似文献   

1995年永登5.8级地震多种前兆异常特征   总被引：3，自引：5，他引：3       下载免费PDF全文

杜学彬  李步云  刘耀炜 《地震工程学报》1997,19(4):19-24

研究了１９９５年７月２２日甘肃永登５．８级地震地电、水化学、水动态、地应力、地形变等５种前兆的异常特征，得到如下结论：①该次地震中短期（１年尺度）和短临异常空间分布符合“异常震源地点发震机制主要活断层”之间的特定关系，近２～３年的中期异常集中分布在西秦岭北缘北西向断裂带和海原通渭武都南北向断裂带上；②震前约１年时间尺度震源区发育起来了北北西南南东向挤压变化突出的附加应力场，并引起断层错动；③源兆集中分布在本次地震震源周围，场兆集中分布在上述两条活动断裂带上．源兆占异常的大多数，场兆占少数．在时间上场兆出现在先，源兆在后．  相似文献   

Separate Analysis of Remote Sensing Information of Structures of Different Geological Periods and Quantitative Study of Corresponding Tectonic Stress Fields   总被引：1，自引：0，他引：1  

Yang Wunian  Zhu Zhangsen Institute of Remote Sensing  GIS  Chengdu University of Technology  Chengdu  Sichuan Liu Xinzhu  Yang Wencai 《《地质学报》英文版》1997,71(3):344-354

The structural feature shown on a remote sensing image is a synthetic result ofcombination of the deformations produced during the entire geological history of an area.Therefore, the respective tectonic stress field of each of the different stages in the complexdeformation of an area can be reconstructed in three steps: (1) geological structures formed atdifferent times are distinguished in remote sensing image interpretation; (2) structuraldeformation fields at different stages are determined by analyzing relationships betweenmicrostructures (joints and fractures) and the related structures (folds and faults); and (3)tectonic stress fields at different stages are respectively recovered through a study of the featuresof structural deformation fields in different periods. Circular structures and related circlular and radial joints are correlated in space to con-cealed structural rises. The authors propose a new method for establishing a natural model ofthe concealed structural rises and calculating the tectonic stress field by using quantitative dataof the remote sensing information of circular structures and related linear structures.  相似文献   

石材荒料开采初析   总被引：1，自引：0，他引：1  

李永贵 《吉林地质》1997,(2)

石材荒料开采初析石材矿山开采过程中遇到的首要问题就是确定最低开采率，即在地质、开采条件具备的前题下，确定采石无亏损，达到石材荒料的最高产出利用率。因此，它与一般利用工业指标去评价矿床、计算矿山的服务年限是有些不同的，这方面当然计算方法不当是主要原因。...  相似文献   

Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background   总被引：2，自引：0，他引：2  

韩渭宾  蒋国芳 《地震学报(英文版)》2004,17(2):230-243

Introduction Both Sichuan and Yunnan are provinces with more earthquakes. Based on catalogue of strong earthquakes in China compiled by the Prediction Department of China Earthquake Administration, there are 639 M5.0 earthquakes during 26 B.C.~A.D. 2001. Among them, 475 are M=5.0~5.9 events, 124 are M=6.0~6.9 events, 39 are M=7.0~7.9 events, and one is M=8 event occurred in Sichuan and Yunnan area. Here is one of the areas where seismic activities are most active in China. Sichuan-Yun…  相似文献   

雅江地块的震兆分析与强震危险性探讨     

程万正 《内陆地震》2004,18(1):20-28

分析了雅江地块的构造环境、地震活动和震兆异常，探讨2001年雅江6．0级地震、2002年新龙5．3级地震发生后雅江地块的强震趋势。重点对理塘-德巫断裂带，新龙、白玉、德格及贡觉一带地区的异常地震活动图像进行分析，认为该区存在强震填空的潜在危险性。  相似文献   

安徽淮河构造变形带及邻近块体现代构造应力场特征   总被引：3，自引：1，他引：3  

刘东旺  刘泽民  沈小七  夏瑞良  李敏莉  闫素萍  凌学书 《中国地震》2004,20(4):364-371

针对安徽省较特殊的构造环境及历史地震分布特点，利用直达波最大振幅比和系统聚类分析方法，在对安徽淮河中游区1974年以来近百个中小地震震源机制反演、聚类及空间合成的基础上，分析了华北断块南缘的安徽淮河构造变形带及邻近块体震源断层滑动方式、构造应力场分布及块体运动方式、应力场随时间变化等。结果显示：淮河构造变形带及其邻近块体上震源断层总体上以近走滑型或斜滑型破裂为主，但倾滑型破裂也占一定比例；该地区构造应力以水平作用为主，但也存在一定的垂向作用。其中淮北和皖中块体仍可能分别向SWW和NEE方向运动，并在淮河构造变形带上产生左旋剪切作用，呈现一定的继承性活动特征；各块(带)上主压应力P轴走向随时间的变化在总体上较为一致，而各时段之间P轴方位存在一定差异，显示安徽淮河中游区受华北和华南应力场的共同作用，但其地震活动可能主要受控于华北应力场。  相似文献   

川西北倒三角形断块东部区域强震带形成机制与地震活动特征     

蒋良文  王士天  李渝生  王运生 《地球科学进展》2004,(Z1)

川西北倒三角形断块东部区域地处青藏高原东部边缘地带,地跨川西北高原及其与四川盆地过渡带的高山峡谷区,属我国著名的南北向地震带的中段,因其特定的大地构造环境和强烈的现代地壳构造运动,导致其在强大的近东西向构造应力场的驱动和平卧“A”字型控震构造体系的控制下,沿两侧边界断裂向东强力楔入,于“构造急剧收口带”之西侧形成了一个近SN向地跨三大构造单元的强震带,强震沿该带有规律的往返迁移和重复发生,且地震活动强弱具有较明显的分形特征。  相似文献