沮漳河现代沉积研究

通过对沮漳河 1994～ 1998年洪水期与枯水期沉积的连续观察研究 ,指出了洪水期与枯水期沉积物搬运的不同机制和过程 ,识别出了 16种岩石相及 6种组合类型 ,每种组合的水动力条件及沉积过程决定了其沉积方式、沉积序列、产出位置和微环境特点。据此 ,将沮漳河可划分为 4个沉积微相单元 :河道内砾石及砂坝 ,典型凸岸点坝 ,决口扇与广布的河漫滩。提出了曲流河两个相邻弯顶之间存在凹岸滩坝的可能性 ,探讨了曲流河“二元结构”的形成过程和加积机理     

东马珠穆沁旗中铁陨石表面的角砾状橄榄石的特征

东乌珠穆沁旗中铁陨石中有二种橄榄石。一种是陨石中基质橄榄石，另一种是镶嵌在陨石表面的角砾状橄榄石。电子探针成分分析结果表明，两种橄榄石中的FeO和MnO比值，包体矿物种类，包体铁纹石和镍纹石中Fe,Ni的含量等，均有较大区别。陨石中基质橄榄石矿物是本陨石中原物质，而角砾状橄榄石是宇宙中物质。他们是两块自由翱于宇宙中的物质碰撞混合而形成的东乌珠穆旗陨石中这种现象。     

Study on the relationship between geothermal exploitation and seismic activity in Xi’an region

Based on the analysis of the induced earthquakes in China and abroad, we get some ideas about earthquakes induced by pumping water out of a well or injecting water into a well. The induced earthquakes usually occur near the well, and they are generally small earthquakes. The earthquake sources are shallow, and they belong to the main shock-after shock type of earthquake or the swarm-type of earthquake. The magnitude and the quantity of the induced earthquakes obviously depend on the pressure and the quantity of water pumped or injected. These earthquakes happen as soon as pumping or injecting occurrence, or after ten or twenty days, they may occur at the time of injecting mud or injecting high pressure water when a well is being drilled, or at the time when the ground water is being normally exploited. A large quantity of hot water has been exploited since 1990 in Xi’an, and the quantity of water exploited has been increasing year by year, as a result the groundwater level has been dropping with the water pumped out and the water level is high in summer and low in winter. The earthquakes in Xi’an region belong to the solitary-type and they spread outside Xi’an city where the wells are concentrated but no earthquake happens. The seismic frequency and the energy released have no relation with the quantity of water exploitation or the water level in the well. It is considered that geothermal exploitation does not induce earthquakes in and around Xi’an because of its specially geological condition. Foundation item: Project sponsored by the Landslide Office of Shaanxi Province and Society of Disaster Reduction of Shaanxi Province.     

Determination of active units with different kinematic property and their activity pattern in North China based on the data from GPS remeasurements

IntroductionWith the most feasible and powerful technical support provided by the high-precision GPS measurement for the study on horizontal crustal deformation, the obtainment of various-scale horizontal movement data and its study over the whole world is now in the ascendant, and its applicable fields is now expanding successively. In China, besides the GPS monitoring networks for different applications arranged by many agencies and departments, the key scientific project Crustal Movement…     

Neuro‐control of seismically excited steel structure through sensitivity evaluation scheme

The neuro‐controller training algorithm based on cost function is applied to a multi‐degree‐of‐freedom system; and a sensitivity evaluation algorithm replacing the emulator neural network is proposed. In conventional methods, the emulator neural network is used to evaluate the sensitivity of structural response to the control signal. To use the emulator, it should be trained to predict the dynamic response of the structure. Much of the time is usually spent on training of the emulator. In the proposed algorithm, however, it takes only one sampling time to obtain the sensitivity. Therefore, training time for the emulator is eliminated. As a result, only one neural network is used for the neuro‐control system. In the numerical example, the three‐storey building structure with linear and non‐linear stiffness is controlled by the trained neural network. The actuator dynamics and control time delay are considered in the simulation. Numerical examples show that the proposed control algorithm is valid in structural control. Copyright © 2001 John Wiley & Sons, Ltd.     

平凉“95．7．19”强对流风暴分析

分析具有代表性的平凉局地强对流风暴过程，揭示了平凉发生强对流天气独特的地形因素。     

Research on the seismotectonics of the Jan－uary 17，1995 Hanshin M7．2 earthquake

ＲｅｓｅａｒｃｈｏｎｔｈｅｓｅｉｓｍｏｔｅｃｔｏｎｉｃｓｏｆｔｈｅＪａｎ┐ｕａｒｙ１７，１９９５ＨａｎｓｈｉｎＭ７．２ｅａｒｔｈｑｕａｋｅＺＨＵ－ＪＵＮＨＡＮ１）（韩竹君），ＦＵ－ＨＵＲＥＮ２）（任伏虎），ＹｕｊｉｒｏＯｇａｗａ２）（小川雄二郎）ａ...     

伊舒断裂带南、北段震源参数研究

利用时间城小地震地震图的方法，研究了震源参数与介质特性的差异。据初步研究结果，伊通－舒兰断裂南、北两段的震源应力降与Ｑ值存在差异。该方法是断层的震源深度范围内介质特性研究的补充，为断裂的分段提供一个重要方法     

大同盆地内砂板梁上断裂新活动及其力学实验模拟

通过野外实地考察、野外现场力学实验及室内力学实验模拟断裂的新活动，来研究砂板梁新隆起的活动构造特征和类型。旨在从实验模拟与野外实践相结合的基础上，对活动构造，特别是对断裂新活动在第四纪松散沉积层中特殊的表现形式进行研究，寻找第四纪松散沉积层中断裂新活动的有效识别标志，这是准确判定断裂新活动的关键，对工程地质评价及区域性地震危险性分析有很好的实用价值     

天水地震区深部地温场的有限元计算

用有限元方法计算了天水地震区上地壳地温场。结果表明，影响该区浅部（层）地温场的主要因素是基底构造和断裂构造。祁连褶皱系为高热异常区，秦岭褶皱系为低热异常区，西秦岭北缘断裂带为地温梯度带。认为该带历史地震的发生与热应力差有关