复杂山地条件、特长、大埋深公路隧道 工程地震勘探技术方法     

王跃飞  龚道平  蔡大江 《物探与化探》2007,31(1):81-85

通过对复杂山地条件、特长、大埋深的雪峰山公路隧道的工程地震勘探实例,介绍和分析了根据实地情况开发和应用的高分辨率地震震源激发技术,复杂地形、地质构造条件下共排列双向变偏移距高分辨率反射波多次覆盖技术,环保型地震反射波与折射波法野外同步施工技术.  相似文献   

鞍山陈台沟地区太古宙花岗岩组成与构造特征     

李斌  金巍  张家辉  王亚飞  蔡丽斌  王庆龙 《世界地质》2013,32(2):191-199

鞍山陈台沟地区出露有大量太古宙花岗质岩石和变质层状岩系,是研究太古代地壳形成与演化的经典地区之一。通过对该区岩石单元、构造特征研究,较系统地划分了岩石单元,具体分析了各单元组构及构造变形特征。细粒奥长花岗质糜棱岩、似斑状花岗质糜棱岩和中--细粒花岗质片麻岩具有古太古代花岗质岩石的特点,共同经历地壳中--深部层次的韧性变形改造。细粒奥长花岗岩为中太古代岩浆事件的产物,表现为非透入性的变形方式和部分韧--脆性形变组构。鞍山群层状变质岩石主要记录了新太古代中--浅部地壳层次的强烈变形事件。中粗粒白云母花岗岩就位,标志早期不同的构造变形作用在新太古代末期基本结束。在此基础上,讨论了本区太古宙地壳的形成与演化过程。  相似文献   

强矿震地球物理过程及短临阶段预测的研究   总被引：1，自引：0，他引：1  

李铁  蔡美峰  冀林旺  左艳  孙丽娟 《东北地震研究》2004,20(3):39-46

用区域强震震源机制解、现场地应力测量、三维有限差分数值模拟方法分析强矿震的孕震环境；通过定量观察采矿与矿震活动的相关性，分析强矿震的诱发原因；基于中尺度地震实验场高密度数字地震和前兆台网的现场观测，用地震学方法和小波工具分析强矿震孕震过程采集到的数据，提取短临阶段的异常信息；通过强矿震的震源机制解判断震源处的应力释放状态。提出地质构造环境、地应力场和采矿活动共同作用诱发强矿震的机理和次生应力场在孕育该震过程起主导作用的观点．发现震前短临阶段存在可信的b值、η值、频次、波速比等地震学异常和定点潮汐形变前兆异常，时异常信息的提取方法和强矿震短临阶段的预测进行了探讨。  相似文献   

祁连山冰川变化及其脆弱性     

CAI Xingran  LI Zhongqin  XU Chunhai 《地理学报(英文版)》2022,32(1):117-140

Glaciers are a reliable freshwater resource in arid regions of West China and the vulnerability of its changes is closely related to regional ecosystem services and economic sustainable development. Here, we took the Qilian Mountains as an example and analyzed the spatiotemporal characteristics of glacier changes from 1998 to 2018, based on remote sensing images and the Second Chinese Glacier Inventory. We estimated the basic organizational framework and evaluation index system of glacier change vulnerability from exposure, sensitivity and adaptability, which covered the factors of physical geography, population status and socio-economic level. We analyzed the spatial and temporal evolutions of glacier change vulnerability by using the vulnerability evaluation model. Our results suggested that:(1) Glacier area and volume decreased by 71.12±98.98 km² and 5.59±4.41 km³, respectively, over the recent two decades, which mainly occurred at the altitude below 4800 m, with an area shrinking rate of 2.5%. In addition, glaciers in the northern aspect(northwest, north and northeast) had the largest area reduction. Different counties exhibited remarkable discrepancies in glacier area reduction, Tianjuan and Minle presented the maximum and minimum decrease, respectively.(2) Glacier change vulnerability level showed a decreasing trend in space from the central to the northwestern and southeastern regions with remarkable differences. Vulnerability level had increased significantly over time and was mainly concentrated in moderate, high and extreme levels with typical characteristics of phases and regional complexity. Our study can not only help to understand and master the impacts of recent glacier changes on natural and social aspects but also be conducive to evaluate the influences of glacier retreat on socio-economic developments in the future, thus providing references for formulating relevant countermeasures to achieve regional sustainable development.  相似文献   

青藏高原近60年来气候变化及其环境影响研究进展     

杨耀先  胡泽勇  路富全  蔡英  于海鹏  郭瑞霞  付春伟  樊威伟  吴笛 《高原气象》2022,41(1):1-10

作为全球能量水分循环的关键区域,青藏高原(下称高原)气候变化对高原及周边地区气候与环境变化具有重要影响.本文从高原表面增暖、辐射变化、降水的多尺度变率、表面风速及环境变化方面回顾了高原近60年来气候变化及其环境效应与物理机制的研究进展,并基于再分析和台站观测资料讨论了近10余年来高原表面温度和风速变化的特征及原因.最后...  相似文献   

影响东海海底管道安全的灾害因素   总被引：1，自引：0，他引：1  

崔征科  蔡春麟  施健  张异彪 《海洋地质前沿》2014,(1):48-54

通过多年的海底管道检测成果,分析了东海海区对管道路由存在威胁的灾害因素,认为可以分为人类活动、海流冲刷、浅部地质灾害和砂质底质等;重点探讨了拖痕、海流冲刷、浅层气和砂土液化等灾害因素的致灾机理和致灾结果,目的是加深对这些灾害的认识,以期在今后的检测中能够及时发现存在的安全隐患,并能采取相应的防范措施,确保海底管道的安全运行。  相似文献   

贺兰山寒武纪早期苏峪口组水下冲积扇的发现及意义     

蔡雄飞  何文键  杨捷  曾佐勋  顾延生  刘伟 《岩石矿物学杂志》2013,32(2):197-206

寒武纪早期的苏峪口组是贺兰山地区地质历史重要转换时期的地质单位,长期被认为是近岸海滩沉积.通过3年来对苏峪口组的研究,新识别了苏峪口组沉积环境为一个水下冲积扇,在岩性、岩相、生物群等方面都有新的发现和新的认识.水下冲积扇以冲刷面为底,砾石成分比较复杂,具砾砂混杂、不等粒结构,内部发育递变层理,具重力流的沉积特征.全区辉绿岩脉锆石年龄集中在5.3～5.4 Ma,是开裂盆地早期出现的标志年龄,说明开裂盆地的出现是造成苏峪口组早中期水下冲积扇发育的主要原因.  相似文献   

Deep Geophysical Structure Research on Middle Section of the Longmen Mountain Tectonic Belt     

YU Nian  WANG Xuben  CAI Xuelin  KAN Aike  LI Jian 《《地质学报》英文版》2013,87(Z1):90-94

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Deep Structure Beneath the Southwestern Section of the Longmenshan Faults and Lushan Ms7.0 Earthquake on 20 April 2013     

ZHAN Yan  ZHAO Guoze  Martyn Unsworth  WANG Lifeng  CHEN Xiaobin  LI Tao  QIAO Qibin  WANG Jijun  TANG Ji  CAI Juntao  WANG Yuanzhao 《《地质学报》英文版》2013,87(Z1):421-424

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Characteristics of the Submarine Topography and its Profile Type of the Coast of China     

CAO Chao  CAI Feng  LI Yan  ZHENG Yongling  WU Chenqiang  LU Huiquan  BAO Jingjing  XU Yan 《《地质学报》英文版》2013,87(6):1724-1742

Based on the latest submarine topography data of the China 908 Project （China offshore marine environmental comprehensive investigation and assessment）,we analyzed the general China offshore submarine topographical characteristics and the factors influencing its development.The submarine topography off the coast of China follows the NW-SE trend of the land topography.The gradient of the submarine topography ranges from 0.2％ to 1.6％ with an average gradient of about 0.8％.The depth contours run mostly parallel to the coast,and extend out to sea in estuary areas.The submarine topography is dominated by the geological structure,which shows the typical characteristics of two uplifts and two subsidence events from north to south.The geological structure combined with the different sedimentary environments and complex hydrodynamic conditions produced topography that can be characterized by three types：sedimentary basins,compressionuplift,and transition form.In the sedimentary basin and compression-uplift regions,the topographical undulation is small,sediments are fine-grained,and the currents flow in a single direction,leading to bays with sedimentary plains and underwater accumulation slopes,which are of the same tectonic origin.Transition-type topography is characterized by strong undulations and mixed-size sediment particles,terraces and scarps inshore and shelf plains and erosion-deposition landforms offshore.This is a result of incomplete fault block development and repeated transgressions.In the deposition reformation regions （transition form type）,the topography has strong undulations,the sediments are coarse,tidal sand ridges are well-developed at terrigenoussupplied estuaries and convergence zones,and the Holocene sediments are thick,transformed by tides,river runoff,and currents.  相似文献