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951.
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
952.
A new formulation is proposed to model pounding between two adjacent structures, with natural periods T1 and T2 and damping ratios ζ1 and ζ2 under harmonic earthquake excitation, as non‐linear Hertzian impact between two single‐degree‐of‐freedom oscillators. For the case of rigid impacts, a special case of our analytical solution has been given by Davis (‘Pounding of buildings modelled by an impact oscillator’ Earthquake Engineering and Structural Dynamics, 1992; 21 :253–274) for an oscillator pounding on a stationary barrier. Our analytical predictions for rigid impacts agree qualitatively with our numerical simulations for non‐rigid impacts. When the difference in natural periods between the two oscillators increases, the impact velocity also increases drastically. The impact velocity spectrum is, however, relatively insensitive to the standoff distance. The maximum relative impact velocity of the coupled system can occur at an excitation period Tn* which is either between those of the two oscillators or less than both of them, depending on the ratios T1/T2 and ζ1/ζ2. Although the pounding force between two oscillators has been primarily modelled by the Hertz contact law, parametric studies show that the maximum relative impact velocity is not very sensitive to changes in the contact parameters. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
953.
利用北京大学地球物理系暴雨监测与预报国家重点实验室发展的有限区域数值预报模式,对1992年16号台风进行了12h数值模拟。时间是从8月31日12时(世界时)到9月1日00时。结果显示:模式预报的台风和实际台风的移动方向一致,移动距离相当。模式清楚地预报出了由台风倒槽所造成的强降水。这表明模式对台风路径、台风降水等都有较强的预报能力。还进行了对比实验,研究地形和积云对流等对登陆台风发展和降水的影响。结果表明:地形对台风的位置和降水有重大影响,积云对流除了对台风强度有影响之外,对台风环流的位置和台风的移动速度也有影响。 相似文献
955.
Mozheng Wei 《大气科学进展》1996,13(1):67-90
ALow-orderModelofTwo-dimensionalFluidDynamicsontheSurfaceofaSphereMozhengWei(CRCforSouthernHemisphereMeteorology,CSIRODivisio... 相似文献
956.
957.
In this paper, a study on the variation of annual frequency of tropical cyclone (TC) and its relation with SST, Southern Oscillation index, sunspot relative number and number of days for specific circulation patterns was made by using 1884-1988 data of annual frequency for Northwest Pacific TC occurrence, which had been corrected to tendencies.Preliminary results indicated that in the variation of annual TC frequency there exist obvious p.6riods of 21, 31, 15 and 6 years and sustaining periods lasting 12 years in average.Well-defined processes of inflexion were observed in 1931, 1959 and 1977 over the past hundred years.The results also suggested insignificant statistic tendency of annual TC frequency increasing (decreasing) in winter/spring (summer/autumn )in the El Nino years.When the stratosphere was in the zonally westerly phase, the northern zonal circulation would abnormally develop and solar activity would enhance to favour the generation and development of TC. 相似文献
958.
阿尔泰山古风化壳研究结果表明,晚新生以来,至少存在两个风化期,形成了不同类型的风化壳,本文阐述这两个风化期的特征及相应形成的风化壳的类型及特点。 相似文献
959.
湖南洞庭坳陷大地电磁测深研究 总被引:1,自引:0,他引:1
介绍了大地电磁测深在湖南洞庭坳陷的主要研究成果。详细分析、推断了洞庭地区的区域构造格局,深部电性结构及壳、幔高导层的分布特点 相似文献
960.
用地层倾角测井资料解释复杂构造的方法 总被引:1,自引:0,他引:1
倾角测井矢量图可以标示出井眼范围内各深度点的地层产状,一定的地层构造形态在矢量图上有一定的倾角矢量组合模式。通过正演计算,总结出了19种褶曲和断层等构造组合模式的样板及在一口井内各构造模式间的“串”、“缺”、“嵌”连接规律。对照组合模式样板进行矢量组合模式识别,采用“倾角矢量逐点叠加法”,可把井眼范围纵向排列的倾角矢量转换成任意方位的地层视产状,绘制构造剖面图。用多个剖面的地层空间坐标数据可绘制倾角构造平面图,确定钻遇构造的形态。据此原理,编制了一套倾角测井构造解释软件系统。 相似文献