MDCB-5型临震信息监测仪模拟未来震级大小计算初探   总被引：1，自引：0，他引：1  

王文祥  杨武洋 《国际地震动态》2002,(4):6-11

根据MDCB－5型临震信息监测仪记录到的某一地震临震异常幅度（电压值）、持续时间（天数）与岩石破裂、地震发生、地震波能量释放的相关性，从地震发生的物理基础出发，推导出了2个计算未来震级大小的理论公式。使用44天的监测数据对该期间发生的5次6级以上地震的震级进行了计算，在相应的震中距范围内计算的震级与实际发生的震级误差小于0．5级，初步说明了该方法应用于实际地震预报具有一定的参考价值。  相似文献   

确定地下管线深度的方法原理研究   总被引：1，自引：0，他引：1  

黄文清 《矿产与地质》2001,15(Z1):596-602

从理论上阐述了利用倾斜磁场最大值点、利用垂直磁场分量峰值点和利用水平磁场分量半极值点确定地下管线深度的原理方法,指出了利用倾斜磁场最大值点确定管线深度时在原理上存在的问题和不实用性,同时从原理上和实用中筛选出了最佳的定深方法-水平磁场分量三角法.  相似文献   

AN AGCM +SSiB MODEL SIMULATION ON CHANGES IN PALAEOMONSOON CLIMATE AT 21 KA BP IN CHINA^*          下载免费PDF全文

CHEN Xing  YU Ge  LIU Jian 《Acta Meteorologica Sinica》2001,15(3):333-345

The numerical simulation experiment of climate at Last Glacial Maximum (LGM.21 ka BP) in China is made by using an atmospheric general circulation model (AGCM) coupled with land surface processes (AGCM+SSiB) and earth orbital parameters and boundary forcing conditions at21 ka.The modeled climate features are compared with reconstructed conditions at 21 ka from paleo-lake data and pollen data.The results show that the simulated climate conditions at 21 ka in China are fairly comparable with paleo-climatological data.The climate features at 21 ka in China from the experiment are characterized by a drier in the east and a wetter in the west and in the Tibetan Plateau as well.According to the analysis of distribution of pressure and precipitation,as well as the intensity of atmospheric circulation at 21 ka,monsoon circulation in eastern Asia was significantly weak comparing with the present.In the Tibetan Plateau,the intensity of summer monsoon circulation was strengthened,and winter monsoon was a little stronger than the present.The simulation with given forcing boundary conditions,especially the different vegetation coverage,can reproduce the climate condition at the LGM in China,and therefore provides dynamical mechanisms on the climate changes at 21 ka.  相似文献   

地震活动期、幕最大地震M1的估计及中-长期地震趋势预测     

张立人  陈正位 《地震》2001,21(1):53-58

提出一种地震活动期、幕最大地震M1的估计方法：利用中低震级累计频度∑N与震级近似的直线关系得到间隔地震频度N与震级的线性关系。用间隔度N与震级的线性关系估计最大地震M1。结果表明，以震级－间隔频率的线性关系估计的M1比震级－累计频度关系得到的M1更接近实际发生的最大地震震级，震级－累计频率关系得到M1通常被高估。基于震级－累计频度关系曲线的特征和震级－间隔频度的线性关系估计的最大地震M1，可为中－长期地震趋势预测提供新的信息。研究表明，中国大陆自1979年开始的地震幕即将结束，而帕米尔东北侧自1915年以来的地震平静期也将结束。  相似文献   

Subaerial river bank erosion processes and their interaction with other bank erosion mechanisms on the River Arrow,Warwickshire, UK   总被引：1，自引：0，他引：1  

Pauline R. Couper  Ian P. Maddock 《地球表面变化过程与地形》2001,26(6):631-646

River bank erosion occurs primarily through a combination of three mechanisms: mass failure, fluvial entrainment, and subaerial weakening and weathering. Subaerial processes are often viewed as ‘preparatory’ processes, weakening the bank face prior to fluvial erosion. Within a river basin downstream process ‘domains’ occur, with subaerial processes dominating the upper reaches, fluvial erosion the middle, and mass failure the lower reaches of a river. The aim of this paper is to demonstrate that (a) subaerial processes may be underestimated as an erosive agent, and (b) process dominance has a temporal, as well as spatial, aspect. Bank erosion on the River Arrow, Warwickshire, UK, was monitored for 16 months (December 1996 to March 1998) using erosion pins. Variations in the rate and aerial extent of erosion are considered with reference to meteorological data. Throughout the first 15 months all erosion recorded was subaerial, resulting in up to 181 mm a^?1 of bank retreat, compared with 13 to 27 mm a^?1 reported by previous researchers. While the role of subaerial processes as ‘preparatory’ is not contended, it is suggested that such processes can also be erosive. The three bank erosion mechanisms operate at different levels of magnitude and frequency, and the River Arrow data demonstrate this. Thus the concept of process dominance has a temporal, as well as spatial aspect, particularly over the short time‐periods often used for studying processes in the field. Perception of the relative efficacy of each erosive mechanism will therefore be influenced by the temporal scale at which the bank is considered. With the advent of global climate change, both these magnitude–frequency characteristics and the consequent interaction of bank erosion mechanisms may alter. It is therefore likely that recognition of this temporal aspect of process dominance will become increasingly important to studies of bank erosion processes. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

新疆暴雨的若干规律性   总被引：20，自引：0，他引：20  

马淑红  席元伟 《气象学报》1997,55(2):239-248

应用熵最大原理导出的公式研究了新疆暴雨时面深分配规律，并通过近４００个水文、气象测站３２ａ资料的分析，发现新疆暴雨的若干规律，这对于新疆暴雨研究和水利工程设计及暴雨洪水灾害防治等都有实用价值  相似文献   

多母体p—范极大似然平差   总被引：2，自引：0，他引：2  

於宗俦  孙海燕 《测绘学报》1997,26(1):42-46

本文提出了多母体ｐ－范极大似然平差方法，建立了该方法的数学模型，并且导出了求解参数估值的基础方程，本文提出的方法溶测量平差，误差母体分布的估计、方差分量估计于一体，是对多元ｐ－范极大似然平差的进一步推广。  相似文献   

青海湟水盆地地壳稳定性的动力学基础   总被引：1，自引：0，他引：1  

王赞军  夏玉胜  涂德龙  张家庆  梁平 《高原地震》1997,(3)

通过对湟水盆地区域震源机制、断层水平运动方式、地层褶皱形态分别反映的现代、第四纪晚期、第三纪构造应力场的对比研究，同时分析1990年以来地震活动图象，得出汉水盆地地壳介质强度可分为三个不同的，为各区未来地震活动强度的预测以及地壳稳定性研究奠定了基础。  相似文献   

Seismicity in Major Seismotectonic Provinces of Iran   总被引：1，自引：0，他引：1  

Mirzaei Noorbakhsh 《中国地震研究》1997,(4)

Seismicity parameters,i.e.,seismic activity rate,X,the so-called Gutenberg-Richter b value(orβ),and maximum possible magnitude,Mmax,for major seismotectonic provinces of Iran are estimated through the application of Kijko and SellevolPs uncertainty models.The uncertainty models facilitated the estimation of seismic activity parameters from incomplete and uncertain data files in the catalog of earthquakes in major seismotectonic provinces of Iran.Zagros has the highest seismic activity rate,and is characterized by the occurrence of mainly small-and mid-sized earthquakes.Kopeh Dagh has the lowest activity rate but is characterized by a greater occurrence of major earthquakes.However,the Makran and Alborz-Azarbayejan seismotectonic provinces are most likely the regions which are capable of generating great earthquakes.  相似文献   

Physical background on estimating b value     

Wei-Qiong Huang  Wen-Xiang Li 《地震学报(英文版)》1997,10(1):107-114

The G-R relation lgN=a-bM (1954) is an empirical formula used widely in the seismicity research. But the linearity of b curves has great difference in different time and space domains. An interested question in this paper is that in how large a space-time-strength domain the b value has certain physical connotation. This study told us that we can get optimal statistical results of b value in those space-time domains which can develop correspondent strong shocks with magnitude interval (M _s≥8.5, 8.0≤M _s<8.5, 7.0≤M _s<8.0). Thus, the possible seismogenic areas in which strong shocks with different magnitude intervals develop can be inferred in different regions of the mainland of China. Finally, some new problems are proposed, such as the delimitation of seismic province, the seismicity parameter determination in seismic hazard analysis and in earthquake predictions by using b value. Contribution No. 96A-0074, Institute of Geophysics, SSB, China.  相似文献