2004, 26(1):1-9.
Abstract:The seismic environment,seismic background in middle-short term and integrative characters of anomalies in short term in the seismogenic process of Minle-Shandan earthquake are summarized systematicaly. On the base of common features of precursors in short term before middle-strong earthquacke in Qilian seismic belt,the main evidences and scientific judgement to short term prediction are expatiatied. Meanwhile,the method,difficulty and perplexed problems associated with the judgment are discussed.
LI Qing-he , RUAN Ai-guo , FAN Xiao-ping , JIN Shu-mei
2004, 26(1):10-17.
Abstract:The present research situation on anisotropy in crust is analysed, and the difficulties in identifing the crust anisotropy by using seismic waves and electricity each respectively are indicated. The forward and inverse methods of studing the features of crust media and extracting crust parameters by combined using elastic and electric anisotropy are intruducted. The results of theoretical and practical data show that the combined study on seismic waves and electricity for anisotropy in crust gives clear physical meaning, it will be a new development fields to research anisotropy.
2004, 26(1):18-23,27.
Abstract:There were a lot of difficulties in two dimensions and three dimensions numerical simulation of electric field of a point source which contains inhomogeneous body in a layered medium based on the apparent resistivity and electrical prospecting in the past days.Now using the numerical solution of the boundary element method the broblems can be solved simply and easily.In this paper,the theoretical study on the boundary element method using in model of 2-D and 3-D inhomogeneous body in a layered medium and the application in the earthquake prediction based on the apparent resistivity are comprelensively recounted and analized.The method will be a solid base for the apparent resistivity using in the research of earthquake prediction.
LI Ying-bin , LIN Yi-yong , LIU Yang
2004, 26(1):24-27.
Abstract:Three limit states of structures in earthquake resistance design are described in detail,and the basic performance levels and target performances of structures are also presented.
YUAN Zhong-xia , WANG Lan-min , LI Min-yong
2004, 26(1):28-31,49.
Abstract:The problems and feasible solutions in using Visual Basic to develop Windows Program for a data processing software of soil dynamics test are discussed,through the analysing and processing flowchart of the data and the design of function modules.The main functions and menus in the software which designed by authors are explained also.
XIA Yu-sheng , WU Hong-yan , ZHAO Wen-fang
2004, 26(1):32-37.
Abstract:The principal,process of research and main functions for "management system of seismic disaster information in Haixi prefecture,Qinghai province", which based on the Mapinfo software platform and using the Mapbasic language,are introduced.According to regional geological structure and humane environment of Haixi prefecture,the seismic disaster forcast model is determined also.
SONG Zhi-ping , WU An-xu , MA Qin-zhong , FENG Zhi-shen , ZHOU Hua-gen , ZHAO Zhen-lin
2004, 26(1):38-43.
Abstract:On the theory of wavelet transform,a digital signal f(x) which can be denoted approximately to an approximation signal ajjf(x) and a detail signal (or decomposition signal) dkjf(x) is analyzed theoretically,and a method for discriminating and removing noises of precursory digital data, and separating high-frequency and low-frequency information from original recording signals is proposed.In the paper,some samples for the method applying to precursory digital data in electromagnetism are given.The study shows that wavelet analysis is a new available method to deal with digital data in electromagnetic precursors.
2004, 26(1):44-49.
Abstract:A new method of determining ground motion parameters according to the destruction state of structure after earthquake, which using the inverse technology, is raised. The mathematical model of inversing ground motion parameters for reinforced frame is found with introducing some assumptions about earthquake effect. One method that was called Forward Step-by-step Comparison is raised. At last three examples are given in this paper,and some questions for further studing are put forward.
FENG Zhi-sheng , MEI Wei-ping , ZHANG Xiu-xia , ZHUANG Ming-long , ZHANG Xiao-yong
2004, 26(1):50-56.
Abstract:The amplitude ratios of short-period geomagnetic humorous wave among the three compnents from Sheshan and Chongming geomagnetic stations, Shanghai city, from 1982 to 1999 are obtained, with the technology of maximum-likelihood method (MLM).By preliminary analysis, the characteristics of long and medium term anomalous variation of the ratio in seismogenic process of moderate-strong earthquakes are declining,turning,then resuming,and the duration is about 1~3 years.Meanwhile the migration characteristics of the anomalous variation from long-period to short-period are found.
ZHONG Yu-yun , ZHU Xin-yun , ZHANG Zhen-feng
2004, 26(1):57-61.
Abstract:The types of earthquake sequence, focal mechanisms,main fault planes and seismic moments of 107 earthquake events with M≥5.0 in Chinese mainland from 1977 to 2001 are gathered.Based on the events the relations between seismic moment and magnitude for different fault properties and different types of earthquake sequence are discussed.The result shows that the relation is linear and the line slops directly relats to the earthquake apparent stress and heterogeneous extend of mediums.For both apparent stress and heterogeneous extend of medium, in the strike-slip fault event are higher than in the non-strike-slip fault event,and in the isolated type of earthquake sequence are lower than in the multiple type of earthquake sequence.
WU Zi-quan , JIANG Zao-feng , WANG Cheng-hu , HAN Hai-hua , ZHAN Ning
2004, 26(1):62-65.
Abstract:According to the measure data of blasting and piling vibration, the difference between fitted K value form the measure data and the specified K value in national standards are discussed in several different aspects. The results show that the explosive quantity has no effect on the inversion of safe distance form measure data in blasting and piling vibration experiments. The main factor that leads to the obvious difference between the two K values, except little influence from the explosive quantity and the error in measure data, is the in-homogeneous medium that is denser near the blasting site and looser far from the blasting site.
LI Xi-guang , ZENG Zuo-xun , LIU Li-lin
2004, 26(1):66-71.
Abstract:Based on analysis and study on the focal mechanism solutions of 50 MS≥2.8 earthquakes in Wuhan-Xinyang area from 1972 to 2001, the current stress field in the area is divided into four districts with their own characteristics, namely Jianghan plain district,Tongbo-Dabie-Huaibei district,West Hubei district and North hubei district.Combining the result of numerical modeling,we find out that:in Jianghan plain district,the principal compressive stress P axes are in a preponderant direction of SE127°,with shallow earthquakes in small magintudes;in Tongbo-Dabie-Huaibei district,the P axes are mainly NE33° and some NW333°,which indicates that the field stress is in a shear condition and most of earthquakes distribute along the strike-slip active faults.The functional mechanism of current stress field to seismicity is seperated and transformed through the main strike-slip active faults in the area.
LIN Chang-you , WANG Shu-ming , SUN Chong-chi , YANG Chang-fu
2004, 26(1):72-77.
Abstract:The one-dimensional anisotropic medium inversion for magnetotelluric data from 10 observational sites distributed in Tianzhou-Yongdeng region is studied and compared with the results of the two-dimensional symmetrical anisotropic medium inversion in the same region.It shows that in most cases the one-dimentional anisotropic inversion could also reveal the main characters of conductivity anisotropic structure of earth's crust. Meanwhile the one-dimensional isotropic inversion could obtain reliable electrical layer boundaries by using some average and characteristic impendences,if the method is suitable.The crustal medium conductivity obtained by the inversion probably is some averagerage value of two principal directions.
WANG Fu-cai , LIU Guang-kuan , ZHANG Qian , JIANG Yan-lin , ZHOU Wei-hong , LI Fen-ru , XUE Jia-fu
2004, 26(1):78-81.
Abstract:The ground resistivity data measured at Gaoyou station,Jiangsu province are processed and analysized by using the differences energy and normalized monthly variation rate methods.The result shows that the anormaly variation of ground resistivity recorded at the station has some prediction ability to moderate and strong earthquakes which near the station and strong shocks occurred in Taiwan.
ZHENG Wen-heng , LIANG Shu-ping , WANG Cheng
2004, 26(1):82-88.
Abstract:A new concept of earthquake occurrence control,and a consideration of using the time reversal method to realize the focusing wave energy in earth crust and triggering earthquake dynamically,are proposed.In the method the technology of ND-FEM emulation is adapted to study the time reversal of wave in un-even,and further more non-linear crustal media,verify the feasibility that focus seismic wave energy on to the potential epicentre.The result shows that it is feasible to focus the wave energy through crust,at least an approximate focus through non-linear crustal media.
Zhang Li-qin , Yu Wen-hui , Wang Jia-ying
2004, 26(1):89-92.
Abstract:In this paper, seismic waves propagating in 3-D discrete media are simulated with pseudo-spectrum method, which using Fourier transform and finite difference to solve wave equation. The result shows:(1) The method has a high computational accuracy.(2) The characteristic of seismic waves propagating shows azimuthal anisotropy even in homogeneous isotropic discrete media.
2004, 26(1):93-93.
Abstract:在中国西藏北纬30度线附近的8级大震有4次,即1411年8级大震,1833年8级大震,1950年8.5级大震和1951年8级大震。在这里雅鲁藏布江的走向和雅鲁藏布江大断层的走向为近东西向,靠近北纬30度线;喜马拉雅山的8 000m以上的4个高峰也近东西向分布,接近30度线。
2004, 26(1):94-95.
Abstract:发震时间:21:27'77";经纬度:39.8°N,97.3°E;深度:33 km;震级:Ms5.9。收集了全省及邻近省份共同31个台站初动后作出震源机制解(表1,图1)。
Sopyright:China Earthquake Engineering Journal