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991.
Wu Fu-chun Song Li-sheng Zhu Xing-guo Wang Feng Jing Bei-ke Dong Xing-hong Fang Wei Zuo Yong-qing 《地震学报(英文版)》2001,14(4):434-439
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. 相似文献
992.
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. 相似文献
993.
A Special Orogenic-type Rare Earth Element Deposit in Maoniuping, Sichuan, China: Geology and Geochemistry 总被引:8,自引:0,他引:8
Denghong WANG Jianmin YANG Shenghao YAN Jue XU Yuchuan CHEN Guangping PU Yaonan LUO 《Resource Geology》2001,51(3):177-188
Abstract: The Maoniuping REE deposit is the second largest light rare earth elements deposit in China, explored recently in the northern Jinpingshan Mountains, a Cenozoic intracontinental orogenic belt in southwestern China. It is a vein-type deposit hosted within, and genetically related to, carbonatite-alkalic complex. Field investigation and new geochemical data of the carbonatites from the carbonatite-alkalic complex support an igneous origin for the Maoniuping carbonatites and related REE mineralization. Carbonatite itself carries rare earth elements which were enriched by hydrothermal solution.
It is known that most of the REE deposits related to carbonatite-alkalic complexes were formed in relatively stable tectonic setting such as cratonic or rifting environment. The Maoniuping deposit, however, was formed during the processes of Cenozoic orogeny. Although the Maoniuping deposit is located in the north sector of the Panxi paleo-rift zone, the rift had been closed before early Cenozoic and evolved into an intracontinental orogenic belt, i.e., the Jinpingshan Orogen, which was formed since later Mesozoic to early Cenozoic. Geochronological and geochemical data also prove that the Maoniuping REE deposit was formed in an intracontinental orogenic belt instead of rift system or stationary block.
The Maoniuping REE deposit is similar to the Mountain Pass REE deposit in many respects such as the high contents of bastnaesite and barite, the low content of niobium, and the common occurrence of sulfides. The discovery of the Maoniuping deposit and other REE deposits during the past two decades suggest a good potential for prospecting REE deposits along the alkalic complex belt located on the eastern side of the Qinghai–Xizang–West Sichuan Plateau. 相似文献
It is known that most of the REE deposits related to carbonatite-alkalic complexes were formed in relatively stable tectonic setting such as cratonic or rifting environment. The Maoniuping deposit, however, was formed during the processes of Cenozoic orogeny. Although the Maoniuping deposit is located in the north sector of the Panxi paleo-rift zone, the rift had been closed before early Cenozoic and evolved into an intracontinental orogenic belt, i.e., the Jinpingshan Orogen, which was formed since later Mesozoic to early Cenozoic. Geochronological and geochemical data also prove that the Maoniuping REE deposit was formed in an intracontinental orogenic belt instead of rift system or stationary block.
The Maoniuping REE deposit is similar to the Mountain Pass REE deposit in many respects such as the high contents of bastnaesite and barite, the low content of niobium, and the common occurrence of sulfides. The discovery of the Maoniuping deposit and other REE deposits during the past two decades suggest a good potential for prospecting REE deposits along the alkalic complex belt located on the eastern side of the Qinghai–Xizang–West Sichuan Plateau. 相似文献
994.
高密度电法在湘西北岩溶石山区找水中的应用 总被引:15,自引:0,他引:15
湘西北岩溶石山区地质构造复杂,岩溶发育且具分布不均匀性,找水难度大,为提高含水构造的异常分辨力,各种物探方法的优化组合中,以高密度电法在确定最佳井位方面发挥了重要作用,它采集的数据量大,对异常特征反映灵敏度高,在湘西北不同的岩溶水文系统中找水,取得了成功的范例。 相似文献
995.
997.
为了定量地研究塔里木北部地区区域的层次结构.拆离构造,特别是同油气地质、圈闭构造密切相关的沉积盖层中的层滑倾滑和推覆滑覆等各种构造的形成机制,对该区沉积盖层进行了较系统的岩石物性和岩石力学标本采集和测试(包括三轴参照实验).依其参数结构特点和地质、物探资料,划分出4套7层区域性层滑系统,并与研究程度较高的中、下扬子区的物性参数、岩性组合和构造特征进行综合对比.最后还进一步阐明了塔里木北部地区特征的前列式冲断构造和含油气局部构造等,均受到这7层区域层滑系统的制约. 相似文献
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