The Cenozoic mantle magmatism and motion of lithosphere on the north margin of the Tibetan Plateau     

Luo Zhaohua  Xiao Xuchang  Cao Yongqing  Mo Xuanxue  Su Shangguo  Deng Jinfu  Zhang Wenhui 《中国科学D辑(英文版)》2001,44(1):10-17

Geodynamic properties and evolution of the lithosphere on the north margin of the Tibetan Plateau are recently hot topics to geoscientists in the world. Have the northern plates been subducting underneath the Plateau? It is still an unsolved problem. One of the keys to solving this problem is to understand the genetic processes of Cenozoic magmas on the north margin of the Tibetan Plateau. However, there is no enough evidence supporting the subduction model. In contrast, a series of evidence indicates that collision-induced huge shearing faults and large-scale crust shortening played a main role in lithosphere motion on the north margin of the Tibetan Plateau. The mantle-derived igneous rocks strictly distribute at the intersections of large strike-slip faults on the north margin of the Plateau. Generation of magmas may be related to local extensional condition induced by strike-slipping faults, which lead to lithosphere gravitational instability and collapse, as well as upwelling of the deep hot material. Heat induced by shearing and carried by upwelling hot material may cause partial melting on H₂O-bearing mantle.  相似文献   

Discrimination Between Foreshocks and Earthquake Swarm from the Change of First Motion Sign     

Chuai Yongqing  Wang Zhaoli  Meng Yanying  Peng Meixuan 《中国地震研究》2001,15(1):57-74

Based on the data of first motion of 11 earthquake sequences with ML ≥ 3.0 recorded by the Telemetric Seismic Network of Shanxi since the 1980s, the first motion characteristics of each earthquake sequence were studied. It is known that earthquake sequences of different types have different consistency characteristics of focal mechanism. The decrease and increase of the first motion contradictory sign ratios could be taken as an index to judge whether there would still be a larger earthquake to come after the earthquake sequence.  相似文献   

A nonlinear time-lag differential equation model for predicting monthly precipitation     

Peng Yongqing  Yan Shaojin  Wang Tongmei 《大气科学进展》1995,12(3):319-324

This paper investigates the nonlinear prediction of monthly rainfall time series which consists of phase space con-tinuation of one-dimensional sequence, followed by least-square determination of the coefficients for the terms of the time-lag differential equation model and then fitting of the prognostic expression is made to 1951-1980 monthly rainfall datasets from Changsha station Results show that the model is likely to describe the nonlinearity of the an-nual cycle of precipitation on a monthly basis and to provide a basis for flood prevention and drought combating for the wet season.  相似文献   

利用EOF作相空间拓展与有限区域大气系统混沌吸引子维数的确定     

朱育峰  彭永清等 《南京气象学院学报》1995,18(1):52-56

提出用自然正交函数分解的方法来开拓相空间，从而研究有限区域上大气系统的混沌性质。与利用时间滞后作漂移来开拓相空间方法相比较，前者充分保证了相空间各基矢量的正交性，弥补了后者只能对单点资料进行计算的不足。文中利用欧洲中期数值天气预报中心1980－1986年北半球亚洲地区的500hPa位势高度场逐日格点资料进行了EOF分解并计算得到了该地区大气系统的分维数为D＝6．2，从而表明，为支撑该地区大气系统的混沌吸引子至少应取7维系统或以7个变量才能作出描述。  相似文献   

神经网络BP模型用于月降水预报的研究   总被引：3，自引：3，他引：3  

严绍瑾  彭永清  郭光 《热带气象学报》1995,11(3):252-257

采用神经网络ＢＰ型三层映射模式，以南京１９４６－１９８５年４０年月雨量为基础序列，确定三层模式的形式。通过不断调整权重系数，作出１９８６年１－１２月的月雨量长期预报，又用同样方法但改用前一个月的实测值报后一个月的月雨量作出１９８６年各月的月雨址预报。平均绝对误差分别为６．０７ｍｍ和５．７３ｍｍ。对１９９４年６、７、８、９月月雨量以４个不同的起始值进行神经网络预测，都得到１９９４年夏季南京特旱的结果，与实测结果相同。  相似文献   

给定参数条件下海温脉动随机模式的混沌行为     

严绍瑾  彭永清 《热带气象学报》1995,11(4):365-369

从Ｓａｌｔｚｍａｎ海气随机气候模式出发，得到了海温脉动θ＇的Ｌａｎｇｅｖｉｎ方程以及对应的Ｆｏｋｋｅｒ－ｐｌａｎｋ方程。在给定参数条件下求数值解，得到的概率密度曲线ｐ（ｘ，ｔ）具有多个极大值，并在ｐ（ｘ，ｔ）－ｐ（ｘ，ｔ＋τ）相空间中呈现Ｃａｎｔｏｒ集合图象，表明该随机系统在上述参数条件下出现了混沌行为。  相似文献   

山西地震活动度的空间分布     

啜永清 《山西地震》1994,(1):37-39

用地震活动度定量描述地震活动性的方法，对山西省有史料记载以来的地震资料，通过Ｓ值空间扫描计算，绘制了山西省地震活动度等值线图。定量地表达了山西省地震活动度的空间分布特征。  相似文献   

JA96－866型ICAP光电直读光谱仪的智能系统设计     

Tian Di  Guan Yongqing  Fu Chunjiu  Yu Shengbao 《吉林大学学报(地球科学版)》1994,(2)

设计了Ｊａｒｒｅｌｌ－Ａｓｂ９６－８６６型电感耦合氩等离子炬（ＩＣＡＰ）光电直读光谱仪与ＩＢＭＰＣ２８６微型计算机的接口适配电路和相应的汇编支持程序，并用ＢｏｒｌａｎｄＣ＋＋２．０面向对象的程序设计语言开发了用户软件，实现了该光谱仪由ＰＤＰ－８Ａ到ＩＢＭＰＣ２８６的计算机换型改造，提高了仪器的智能化水平。  相似文献   

Determining the permeability of fractured rocks based on joint mapping     

Zhang F  Zhou Z  Huang Y  Chen Z 《Ground water》2004,42(4):509-515

A typical fractured rock mass is intersected by several sets of discontinuities, which provide the main flowpath for ground water. Due to the limitations of data obtained by conventional field measurements, it is often difficult to estimate the anisotropic permeability tensor associated with the joints existing in the rock mass. For that reason, determining permeability tensors for fractured rocks is an important topic in rock mass hydraulics. Based on field surveys, joint parameters can be analyzed by using probabilistic and statistical tools, and three-dimensional mapping of the jointed rock mass. Through analysis of a single joint's hydraulic characteristics, the principal value of the permeability tensor for the jointed rock mass can be determined by using Monte Carlo methods and the searching percolation trace method, which is developed in this paper. The study reports on practical examples demonstrating that results from the methods discussed in this paper are in agreement with those from field hydrogeological surveys and measurements.  相似文献   

Sequence stratigraphy of Jurassic-Cretaceous boundary strata in Luanping,Northern Hebei,China   总被引：1，自引：0，他引：1  

TIAN Shugang  LIU Yongqing  LI Peixian  PANG Qiqing & NIU Shaowu . Institute of Geology  Chinese Academy of Geological Sciences  Beijing  China  . Shijiazhuang Economic College  Shijiazhuang  China  . Tianjin Institute of Geology  Mineral Resources  Tianjin  China 《中国科学D辑(英文版)》2004,47(7):607-617

Division and correlation of terrestrial J-K bound are a knotty-argued problem. The key to solving the problem is to find a deposition-continuous section. Owing to stratigraphic hiatus and organism-phylogeny break, we have been discussing the problem without any unitary criterion for several decades. Tectonic ac-tivities occurring strongly in the J-K transitional pe-riod caused commonly sedimentary omissions and frequently volcanic eruptions in northern Hebei Prov-ince, western Liaoning Prov…  相似文献