共和地震前后中小地震的波谱变化   总被引：8，自引：0，他引：8  

许健生  尹志文 《地震地磁观测与研究》1998,19(4):30-36

利用ＣＤＳＮ兰州台的短周期（ＳＰ）地震记录资料,对１９９０年４月２６日青海共和７．０级地震前后发生在该地区的３５个前,余震作了波谱分析工作。结果表明,主震前,共和地区小地震的纵,横波位移谱的拐角频率比值ｆｃ（Ｐ）／ｆｃ（Ｓ）为１．８左右。主震后,拐角频率比下降到１．３左右,１９９５年以后,拐角频率比值又上升到１．５左右,拐角频率比值有可能成为监测孕震区内应力状态变化的测振学指标。  相似文献   

A diagnostic study on the relationship between the assembling of low frequency waves in the pacific ocean and the abnormality of the subtropical high     

Zhang Jianwen  Yu Shihua 《大气科学进展》1998,15(2):247-257

ＡＤｉａｇｎｏｓｔｉｃＳｔｕｄｙｏｎｔｈｅＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｎｔｈｅＡｓｅｍｂｌｉｎｇｏｆＬｏｗＦｒｅｑｕｅｎｃｙＷａｖｅｓｉｎｔｈｅＰａｃｉｆｉｃＯｃｅａｎａｎｄｔｈｅＡｂｎｏｒｍａｌｉｔｙｏｆｔｈｅＳｕｂｔｒｏｐｉｃａｌＨｉｇｈＺ...  相似文献   

相对论效应及其对GPS技术的影响     

李学逊  王兰涛  李少元 《测绘科学》1998,(1)

本文根据相对论基本原理,系统地阐述了GPS中必须仔细考虑的几项主要的相对论效应,包括运动时钟的时间膨胀、引力频移以及地球自转引起的Sagnac效应等,并对相对论效应在GPS中的实际应用进行了定量分析和讨论。  相似文献   

Statistical estimation of corner frequency and its application to seismic event-identification     

G.R. Dargahi-Noubary 《Soil Dynamics and Earthquake Engineering》1998,17(5):297-309

A statistical method is proposed for estimation of the corner frequency. It is based on inference for a stochastic model whose short-term behavior resembles the established source time functions. Properties of the estimates are investigated and some numerical examples are presented. A discussion concerning earthquake–explosion discrimination and the way corner frequency can be related to the rate of zero-crossings is also included. The paper is concluded with some numerical examples.  相似文献   

Frequency response of tiltmeters and tidal factor     

Jun Yang 《地震学报(英文版)》1998,11(4):455-465

The relation of tidal factor value to tiltmeter type has been founded from the harmonic analysis for observational data. The relation is deducted theoretically. It is discovered that the frequency responses of different type tiltmeters and operative periods or damping constant are slightly different in same station. The tiltmeter of small operative period is able to receive more precursory information. That is the tidal factors obtained from harmonic analysis for observed data on tiltmeter of different damping constant are different. The relation between frequency response and tidal factor is searched. It is necessary to calibrate absolutely tiltmeter to predict earthquake. In order to obtain any amount of ground tilt information, it is necessary to select appropriately different frequency tiltmeters to make comprehensive observation. The study is sponsored by the Chinese Joint Seismological Science Foundation, No. 91100.  相似文献   

强震序列叠加时h值计算及其震情预测应用   总被引：2，自引：1，他引：1  

杨欣  俞兴宝 《中国地震》1998,14(4):52-61

在强震群活动中定量计算并扣除前面强震序列的影响是正确估算后续强震序列频度衰减系数ｈ值的关键。  相似文献   

Using the TCEV distribution function with systematic and non-systematic data in a regional flood frequency analysis     

F. Francés 《Stochastic Environmental Research and Risk Assessment (SERRA)》1998,12(4):267-283

Due to the social and economic implications, flood frequency analysis must be done with the highest precision. For this reason, the most suitable statistical model must be selected, and the maximum amount of information must be used. Floods in Mediterranean rivers can be produced by two different mechanisms, which forces the use of a non-traditional distribution like the TCEV. The information can be increased by using additional non-systematic data, or with a regional analysis, or both. Through the statistical gain concept, it has been shown that in most cases the use of additional non-systematic information can decrease the quantile estimation error in about 50%. In a regional analysis, the␣benefit of additional information in one station, is propagated to the rest of␣the␣stations with only a small decrease with respect to the at-site equivalent analysis.  相似文献   

Micro-sequential contour blasting—how does it influence the surrounding rock mass?     

Agne P. Rustan 《Engineering Geology》1998,49(3-4):303-313

The optimal delay time between the contour holes in rock blasting has been studied by theoretical and empirical research in Sweden, regarding ground vibrations, increase in crack frequency, radial crack length and finally overbreak (half cast factor). The model test presented in this paper concerns controlled contour blasting in tunnelling and the full-scale blasts concern tunnelling, road cutting, and dimensional stone quarrying. The results indicate that the microsequential contour blasting technique (contour holes fired in sequence and with a delay in the order of 1–2 ms) is superior to simultaneous initiation both regarding blast-induced ground vibrations and crack frequency increase in the rock mass. Both these evaluation methods reflects the conditions deeper in the remaining rock mass. Simultaneous initiation, however, is superior to micro-sequential contour blasting both regarding the half cast factor and the length of radial cracks emanating from the blastholes. These two parameters are more related to the surface conditions after blasting. The industrial applications of this new knowledge are the use of micro-sequential contour blasting when ground vibrations are of greater concern than the contour, for example, in trench blasting or quarrying in urban areas, and the use of simultaneous initiation when an even rock surface is of high priority.  相似文献   

年降水量和年径流量序列中特大（小）值分析处理方法研究     

曹升乐  于翠松 《水文》1998,(2):22-26

本文针对年降水量序列和年径流量序列中存在特大（小）值的问题,提出了实测序列中特大（小）值的检验方法及其重现期的确定方法,给出了含有特大值序列的分析计算方法。对山东省胶东地区部分主要河流年降水量和年径流量序列进行了分析,重新评价了该地区的降水资源及地表水资源。  相似文献   

大地电磁标定曲线的畸变及校正     

谭捍东  魏文博 《现代地质》1998,12(4):603-606

以野外实际工作为例,对大地电磁测深系统中磁探头的响应函数进行分析,总结了转角频率的偏高或偏低与视电阻率和相位曲线畸变之间的关系,提出了合理的校正方案。  相似文献