大同侏罗纪煤层槽波频散特性及振幅特征     

宋玉平  刘天放 《煤田地质与勘探》1996,24(6):49-53

用数学模型的方法对大同侏罗纪煤田的１５个煤层进行频散和振幅分布模拟：夹矸大于０．２ｍ时，对频散和振幅分布有影响；对地质非对称模型，最大振幅偏离煤层中心。  相似文献   

震电磁效应的实验室研究     

钟清  杨辟元  林天亮 《物探与化探》1996,20(1):58-63

简要介绍了一种新的地球物理方法──震电磁效应法,及一种自行研制的用于实验室的测试装置,列举了用此仪器测试岩矿石标本的例子。实验表明,信号的产生与岩矿石发生破裂有关,不同岩矿石震电磁信号的频谱特性是不同的,因而利用这些特性可以提取有用的信息。  相似文献   

半空间非水平层状介质瑞雷面波的频散方程   总被引：2，自引：0，他引：2  

牛滨华  何继善 《物探与化探》1996,20(5):345-350,358

由于工程勘察中的一些特殊情况,使面波以往的一些理论和结论受到了不同程度的限制。本文从弹性动力学虚功变分原理出发,在重点分析自由表面外力提供的能量来源时,引入了等效面波(能量)震源概念。然后用有限元法建立了半空间多个非水平层状介质瑞雷西波的频散方程。这项工作有助于面波理论和应用技术的发展完善。  相似文献   

1991年江淮特大暴雨与东亚大气低频振荡   总被引：42，自引：3，他引：42  

陆尔  丁一汇 《气象学报》1996,54(6):730-736

本文分析了１９９１年江淮特大暴雨期间东亚大气低频振荡活动。从低频振荡特征看，江淮雨量和东亚风场中低频振荡现象是普遍存在的，风场的振荡周期具有显著的地域和频域分布特征。从低频波的传播看，这一梅雨过程的两个异常阶段（５月下半月和７月上半月），东亚风场低频波的水平传播方向发生了显著的变化。分析指出，低纬地区低频波虽有不同传播方向，但都将暖湿空气以低频形式输送到江淮以南，它与北侧的低频冷空气在江淮地区相互作用，从而导致该地区以低频形式出现的３场特大暴雨。  相似文献   

多遥感卫星接收系统和其数据接收     

王新民  韦银高  王万玉  赵克明 《遥感学报》1997,1(3):198-203,242

该文叙述了单遥感卫星接收系统升级改造为多卫星接收系统所进行的研制工作。包括天线跟踪系统与高频信道的改造，卫星捕获软件的开发，中频接收解调设备的研制以及系统的总装调试等。  相似文献   

青藏高原感热加热异常与夏季低频环流的数值研究   总被引：5，自引：1，他引：5  

朱乾根  管兆勇 《南京气象学院学报》1997,20(2):186-192

使用科学院大气物理研究所两层大气环流模式，就青藏高原地表感热通量异常减少对夏季东半球大气环流及亚洲季风低频变化的影响进行了数值试验研究。结果表明：高原地区感热通量异常减少时，南海及西太平洋地区低频振荡方差百分率增大；高原感热异常加热对东亚和印度季风子系统具有不同的影响，季风区低频扰动的位相，中高纬低频扰动的结构，强度和经向传播速度都发生改变，ＥＡＰ波列变得更为清楚典型，大圆上的低频涡旋一直传播到我  相似文献   

Hydrological impacts of flow regulation associated with the Upper Nepean water supply scheme,NSW     

《The Australian geographer》1995,26(1):71-86

The upper Nepean River has been progressively regulated for water supply to Sydney and Wollongong since 1886 by the Upper Nepean Water Supply Scheme which consists of four large dams, two small dams and two diversion weirs. Secular rainfall changes produced periods of high rainfall and large floods (flood‐dominated regimes) between 1857 and 1900 and 1947 and the present, and an intervening period (1901–46) of low rainfall and small floods (drought‐dominated regime). Upstream impoundment and flow regulation significantly reduced flood magnitudes for most return periods during both types of flood regimes. The probability distribution of mean daily flows was also changed significantly by flow regulation such that during the drought‐dominated regime, the high and low frequency flows were reduced substantially but the moderate frequency flows were increased due to dam releases; the change from a regulated drought‐dominated regime to a regulated flood‐ dominated regime resulted in a substantial increase in discharge for most durations; and increased water diversions to Wollongong during the current flood‐dominated regime produced a marked downward shift in the whole flow duration curve. Nepean Dam reduced downstream suspended sediment yields by two orders of magnitude because it traps in excess of 99 per cent of the inflowing suspended sediment load. Streamflow releases are urgently required from the two diversion weirs to improve downstream water quality and to ensure the viability of the resident ‘potentially threatened’ eastern Macquarie perch (Macquaria nov. sp.).  相似文献   

Towards the identification of later seismic phases     

C. Tong  B. L. N. Kennett 《Geophysical Journal International》1995,123(3):948-958

  相似文献   

云南及其邻近地区地震活动的模式识别     

钱兆霞  李晏平  龙晓帆 《地震研究》1988,(1)

本文用模式识别方法(CORA—3修改方法)研究了云南及其邻近地区大地震的发生时间与中强地震活动特性的关系。结果表明(不分子集):M≥7.0级大震前1—2年内,5—5.9级地震频度有明显增强。前1年6—6.9级地震相对减弱,前2—4年内6—6.9级地震可增至一定水平。对于CORA—3修改算法在采用“CLUSTERS”算法和不用“CLUSTERS”算法所得识别分类结果基本一致。FH(future history test)试验表明,用1930—1986年为学习时段,1969—1986年为预测时段。得到D类识别率为0.6,N类误识率为0.38。  相似文献   

Scaling of peak ground motions from digital recordings of small earthquakes at Campi Flegrei,southern Italy   总被引：2，自引：0，他引：2  

Giuseppe De Natale  Ezio Faccioli  Aldo Zollo 《Pure and Applied Geophysics》1988,126(1):37-53

The dependence of peak ground acceleration and velocity on seismic moment is studied for a set of small earthquakes (0.7<M _L<3.2) recorded digitally at distances of a few km in the Campi Flegrei volcanic area near Naples, Italy, during the ground uplift episode of 1982–1984. Numerical simulations, using the -square spectral model with constant stress drop and ane ^–kf high frequency decay, fit well both the velocity and acceleration data for an averagek=0.015. The observed ground motions in the 1–24 Hz frequency band appear to consist of radiation from simple sources modified only slightly by attenuation effects. Moreover, the scaling of peak values agrees closely with those determined in nonvolcanic areas, once the difference in stress drop is taken into account.  相似文献