地震活动相关性定量方法及其在印度板块动力触角对中国西部地区地震影响中的应用          下载免费PDF全文

杨立明  梅秀萍 《地震工程学报》2005,27(4):317-321

针对地震活动相关性分析的实际需要,提出了一种定量分析不同区域地震活动相关性的方法。以此研究了印度板块东、西触角强震对青藏块体地震活动的影响,结果表明阿萨姆地区的强震活动与青藏块体的强震活动具有很高的相关性,而帕米尔地区的强震影响较小。通过与R值评分及基于板块动力作用分析结果的比较,证实了本方法的有效性。  相似文献   

剩余时差校正及泊松比反演          下载免费PDF全文

王云专  杨立伟  李素华 《地球物理学进展》2005,20(1):214-218

利用突出泊松比变化的Shuey简化方程推导出逐点计算泊松比的反演公式.在泊松比反演之前，对地震数据进行剩余时差校正，可以使振幅随炮检距（或入射角）的变化趋势更明显，可以提高反演的精度.通过对理论模型及实际资料的处理，说明这种反演方法是可行的，由反演结果可以预测低泊松比异常，寻找天然气.  相似文献   

淮安五河口特大桥大口径灌注桩施工实践     

刘效良  李宏伟  董军 《安徽地质》2005,15(1):56-60

介绍了使用大口径钻机，采用泥浆护壁气举反循环回转钻进工艺、进行淮安市五河口特大桥大口径灌注桩施工的工程实践。通过不断提高施工技术措施，摸索与总结出一套成孔施工经验，顺利地完成了施工任务。  相似文献   

西藏松西地区辉绿玢岩岩石化学、地球化学特征及构造环境     

钟华明  王贵生  夏军  童劲松  鲁如魁 《安徽地质》2005,15(3):170-174

青藏高原南羌塘石炭纪-二叠世地层中侵入大量的辉绿玢岩岩墙群，其侵位时代为晚古生代。区域资料显示，这一时期该地区处于冈瓦纳大陆北部边缘。岩石化学、地球化学特征表明，辉绿玢岩与洋脊型、洋岛型及典型的大陆裂谷玄武岩都有明显区别，显示出大陆拉张带（或初始裂谷）的拉斑玄武岩特征。辉绿玢岩是冈瓦纳被动陆缘在晚古生代裂解的产物。  相似文献   

山西交城断裂交城县城段的位置及其与地裂缝的关系研究     

徐扬  赵晋泉  张大卫  杨政 《山西地震》2005,(Z1):22-23

山西交城断裂为太原盆地西界的主控边界断裂,断裂带附近历史上曾发生过6级地震.野外调查发现,沿交城断裂发现多处地裂缝.在交城县城北侧的坡底村-田家山村西一带地裂缝断续出露,裂缝与基岩隆起区与盆地倾斜平原的分界线的距离大约为200 m.  相似文献   

Research on anisotropic parameters by syn-thetic seismogram     

范小平  李清河  杨从杰 《地震学报(英文版)》2005,18(2):196-205

Introduction The anisotropy of the Earth crust medium is a common phenomenon(Crampin,1984).More and more observation materials and study results have proved that on most of the Earth′s upper crust is spread fluid-filled cracks and microcracks,which are aligned according to the contempo-rary stress-field.Such distributions of aligned cracks show effectively anisotropy to seismic wave and the phenomenon is called extensive-dilatancy anisotropy(EDA)(Crampin et al,1984).At the same time,it is …  相似文献   

Inversions for MT data in 2D symmetrical anisotropic media     

杨长福  林长佑  孙崇赤  李清河 《地震学报(英文版)》2005,18(3):361-367

Introduction Ready and Renkin (1971) were the first to make the research on anisotropy problems in magnetotellurics (MT). The progress in the research is not evident because it is more complex and difficult than isotropic problems. Now, the one-dimensional (1D) anisotropy problems in MT have been well solved, while for the two-dimensional (2D) cases, the numerical solutions have only been obtained for some particular conditions (Ready and Renkin, 1975). As to the three-dimensional (3D) ani…  相似文献   

Study of statistically correcting model CMAQ-MOS for forecasting regional air quality     

XU Jianming  XU Xiangde  LIU Yu  DING Guoan  CHEN Huailiang  HU Jiangkai  ZHANG Jianchun  WU Hao  LI Weiliang  HE Jinhai  YANG Yuanqin  WANG Jiahe 《中国科学D辑(英文版)》2005,48(Z2)

Based on analysis of the air pollution observational data at 8 observation sites in Beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution emission inventory and improves the forecast level of air quality. Also this work employed a way of combining point and area forecasting, i.e. taking the products of CMAQ for a center site to forecast air pollution for other sites in vicinity with the scheme of model products "reanalysis" and average over the "area".  相似文献   

Characteristics and genesis of maghemite in Chinese loess and paleosols: Mechanism for magnetic susceptibility enhancement in paleosols   总被引：4，自引：0，他引：4  

Tianhu Chen  Huifang Xu  Qiaoqin Xie  Jun Chen  Junfeng Ji  Huayu Lu 《Earth and Planetary Science Letters》2005,240(3-4):790-802

Morphological characteristics and microstructures of magnetic minerals extracted from Chinese loess and paleosols were investigated using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Our results indicate that maghemite in loess–paleosol sequences was transformed from magnetite through oxidation of magnetite. Maghemite transformed from eolian magnetite during chemical weathering has low-angle grain boundaries among maghemite nano-crystals. Some nano-crystalline maghemites with nanoporous texture resulted from microbe-induced precipitation of magnetite or transformation of poorly crystalline ferric Fe (oxy)hydroxides in presence of Fe-reducing bacteria. Aggregates of euhedral maghemite nano-crystals were transformed from magnetite magnetosomes. Both microbe-induced nanoporous magnetite and microbe-produced magnetite magnetosomes are directly related to microbial activities and pedogenesis of the paleosols. It is proposed that the formation of nano-crystalline maghemite with superparamagnetic property in paleosol results in the enhancement of magnetic susceptibility, although the total amount (weight percent) of magnetic minerals in both paleosol and loess units is similar. Our results also show that nano-crystalline and nanoporous magnetite grains prefer to transform into maghemite in semi-arid soil environments instead of hematite, although hematite is a thermodynamically stable phase. This result also indicates that a decrease in crystal size will increase stability of maghemite. It is also inferred that surface energy of maghemite is lower than that of hematite.  相似文献   

Characteristics of Energy Accumulation and Release of Seismogenic Tectonics and Seismic Risk Analysis in Some Areas in the Tianshan Mountains, Xinjiang1     

Shen Jun 《中国地震研究》2005,19(1):1-11

INTRODUCTIONHowtocombinethestudyofseismogenictectonicswithearthquakepredictionisanurgentscientificdifficulty .Thereexistbiggapsbetweenstudymethodsandcurrentknowledgeonseismogenitectonics ,earthquakeprediction ,seismogenesisandthephysicsofearthquakeoccurre…  相似文献