Wang Changling , Tao Shufen , Zhang Shiqin , Zhang Xinji , Zhang Hui , Zhang Peishan
1996, 18(1):1-7,21.
Abstract:The features of Hydrochemical precursory fields of the Tangshan and Songpan Ms>7.0earthquakes have been studied. The results show that the precursory fields of the two earthquakes have the similar property. The proportion of long-term and imminent anomalies to all anomalies is inversely proportional to epicentral distances. The long-term and imminent anomalies in the focal areas emerge earlier than those in the area far away from foci. All thelong-term anomaly patterns show gradually rising. The formation of hydrochemical precursory field has something to do with regional stress field,but has even closer relation with focal stress field. Focal stress field in the precursory process may play a main role.
Mao Ke , Guo Daqing , Li Qinmei , Zhang Hui , Zhen Tianxin , Guo Wendi
1996, 18(1):8-15.
Abstract:In this paper, based on the analysis of seismicity, crustal deformation and other precursory data, the authors indicated that the regional anomalies in the southeast of Gansu Province before and after the Jingtai Ms 6.2 earthquake in 1990 are characterized by small changing speed,a synchronous start time,different mechanics natures reflected by different anomalies,and so on. These accord with the anomalous changes of crustal deformation and seismicity. It is considered that the group anomalies in the southeast of Gansu before the Jingtai Ms 6.2 earthquake are regional precursor of the Gonghe Ms 7.0 and Jingtai Ms 6.2 earthquakes. The sustained anomalies after the earthquake reflected the stress adjustment within a vast area.
The structure conditions in the Southeast of Gansu have their specific characters. The southeast of Gansu likely is one of the common adjusting regions of the sib and the 6th strong earthquake clusters along the North-South earthquake zone.
1996, 18(1):16-21.
Abstract:In this paper, the different existence forms of radon in underground water are expounded, the mechanisms in which different forms of radon travel and pass the information of crustal stress and strain are discussed and the differences of their reflecting earthquake efficiency are studied. The results show that escaping radon reflects better the crustal stress and strain and earthquake than dissolved radon. Thus, escaping radon can become a new and sensitive reflecting earthquake component of observation net of hydrochemistry for predicting earthquake.
Peng Zizheng , Wang Danye , Xu Yunting , Niu Zhiren
1996, 18(1):22-28,26.
Abstract:In this paper,the percolation of rock fracture is studied by using computer simulation method,and when micro-fractures distribute randomly,fracture cluster distribution pattern,fracture cluster size distribution law,total fracture cluster number, cluster mean size,b value,percolation fractal dimension D,critical case and so on are given. The results according with other models and laboratory experiments show that the percolation mode is a suitable model for describing rock fracture process. Two turning points in rock fracture process are found,thus authors point out that studying macroscopic character of rock nearby those two turning points can better research precursory character in seismogenic process.
Liang Zibin , Zhao Heyun , Cai Hongwei
1996, 18(1):29-35.
Abstract:Based on the method of reconstructing dynamic phase space, this paper calculates the fractal dimension,Lyaponove index and complexity of the resistivity data gained from several stations around Tangshan area before and after the Tangshan earthquake and from Shandan station in 1990. The results show that the time sequence of ground resistivity is of fractal dimension structure,and under normal condition its attractor's dimension is about 2.5. The calculation of its complexity suggests that the change of ground resistivity is far more complicated than other standard attractors.
1996, 18(1):36-41.
Abstract:This paper discussed the relation between the quiescence of M≥5 shocks and the M≥7 earthquakes in China continent since 1900. Furthermore,the seismic tendency and the seismic quiescence(M≥5) for 134 days in 1994 has been preliminarily analyzed.
1996, 18(1):42-46.
Abstract:The paper discussed the relation of gas suddenly released from the crust with earthquake, volcano and unexpected flood,expounded mechanism of the irregular path of the 24th typhoon in 1994 and studied the mechanism in which gas released suddenly from the crust may cause unexpected flood.
Xia Yusheng , Zhao Heyun , Qian Jiadong , Liang Zibin , Sun Hongbin
1996, 18(1):47-51.
Abstract:Through study of the characteristics of strong earthquake activities in the Western China, it is found that strong (M≥6) earthquakes form three groups of gaps with different directions, which are nearly equidistantly distributed. The distance between two gaps is about 5°,and the width of one gap is 1°. This paper gives a preliminary explanation about it by supposing the plateau boundary is being affected by periodical forces. It is considered that such phenomenon may be due to the stationary wave which is formed by the superposition of stress waves created by three groups of periodical boundary forces. Moreover the wave lengths of such stress waves are very similar to those of structural waves obtained by other researchers in the past.
Peng Weirong , Min Xiangyi , Zhang Youmin , Chang Qianjun , Wang Bin , Yin Zhiwen , Zhang Yu , Li Fake
1996, 18(1):52-55.
Abstract:This paper brieny introduces the test system of international seismic data exchange and the structure,particularities, function and process of the real-time data acquisition and transmission system,as well as digitization of seismic data.
Bo Wanjn , Xie Juemin , Xong Fucheng
1996, 18(1):56-60.
Abstract:In this paper,the methods for processing data measured across faults and the results of their application to earthquake prediction are systematically introduced and summarized. A fitting method of deformed parameter with distinct period is presented. As. an example of Yanjiatai vertical base line,the method is proved to be practical for getting rid of noise and extracting the crustal deformation anomalies. The method and indexes for judging seismic three elements by using faults movement data are also presented,and based on them the problem of determining risky area is emphatically discussed.
He Wengui , Liu Baichi , Lu Taiyi , Yuan Daoyang , Liu Xiaofeng
1996, 18(1):61-66.
Abstract:In this paper, based on the 1: 50, 000 active fault mapping, the Holocene activity of faults in the Tianzhu basin and evolutionary process of the basin are discussed. The results show that the faults are very active in Holocene. There was an earthquake in 3980±50 a B.P.. Tianzhu basin is a typical pull-apart basin and its forming and evolution are closely related with the active faults.
Wang Xiusheng , Zhang Xiuxiang
1996, 18(1):67-70,76.
Abstract:The results of comparative observation experiment at Xi'an geoelectric station show that the decay of ambient noise is very quick. If the distance of geoelectric measurement zone from the interference sources is 200 m,the noise level will be reduced by one order of magnitude.It means that a better geoelectric station can be selected nearby a big city and there is the problem of selecting optimum polar distance for any given geoelectric station.
Zou Mingwu , Pan Yingling , Yang Baoping , Zhang Jialiu
1996, 18(1):71-76.
Abstract:Based on the theory of error,analysis on several factors which affected the short-range leveling accuracy in the Mime Basin and in-site test were done. The result shows that the accuracy of short-range leveling was mainly affected by four interference factors as follow: (1)error of leveling rod length which was caused by change of temperature; (2)the instrument warmed only on one side; (3)sinking of rod stake F (4)photo-refraction error on ground. It is emphasized that the fourth factor was more disadvantageous than the others. Therefore,some advanced measures against the disadvantageous factors were adopted and abvious effect was obtained, the observed precision was raised from ±0.40 mm/km to ±0.26 mm/km.
1996, 18(1):77-82.
Abstract:The active band-pass filter is designed by using the modern network theory and multinomial synthetic filter and by modulating and calculating repeatedly through the examination of charts. Its frequency-response curve and circuit structure completely satisfy the needs of various technical indexes. This paper discusses in detail the theoretical basis of the design from unit circuit to full-pole and multi-feedback filter network circuit,as well as the methods of calculating and debugging the parameters of various subbranch circuits. These circuit structures are simple and reasonable, and very easy to modulate and repair. Thus they replace the large-scale inductance and capacitance, and help miniturize the installations.
1996, 18(1):83-83.
Abstract:1995年7月22日6时44分,甘肃省永登县发生了Ms5.8地震.经甘肃省地震监测台网测定,该次地震的震中位置为北纬36°3'7,东经103°17',震源深度10km。震后收集甘肃及其邻近地区32个地震台站的P波初动符号,作出震源机制及其参数,见下表和图l。
1996, 18(1):84-86.
Abstract:长春地震台的地电和地磁两种观测手段建在一起,观测结果表明地电供电系统对地磁观测造成了不同程度的干扰。主要干扰表现为GSI仪器观测时找无声区间的时候发生困难;Cj6仪器观测时使磁针发生摇摆不停,很难找到磁针的影子;CHD5仪器观测时读数不稳定;CB3型、57型磁变仪工作不正常,尤其是Z变线发生断续,影响正常观测工作。作者对地电供电系统对地磁观测的影响进行了试验分析,找到了一个地电布极和导线架设与地磁记录室的最佳相对位置。
1996, 18(1):86-86.
Abstract:由中日两国学者联合撰写与主编的专著《数理地展学进展)(中、英文版)已由地展出版社公开出版发行。
Feng Deyi , Nie Yongan , Wu Guoyou , Chen Huaran , Guo Ruizhi
1996, 18(1):87-95.
Abstract:Tea relatiohehips between wavelike phenomena in the earth's interior,tectonic structure and earthquakes are dicussed. FOur types of generalized tectonic waves are introduced. They are: the ultra-long-period tectonic weves which are synthetical tectonic results in different earth history;the long-period (from several year. to tens of years of different kinds and velocities) tectonic waves reflected by migrtions of earthquake activity,so-called seismicity waves;the medium -period (from several months to several years) tectonic waves reflected by three threestage development process of earthquake Precurors; and the short-period (from sereral minutes to seseral days)tectonic waves recorded by changes in ground water level.tilt,gravity,seismic waves,electromagnetic radistiou,earth sound,and the others. Seismicity waves of three types are interpeted as generalized Rayleigh tectonic weves,generalized Love tectonic waves and generalized channel tectonic waves. Finally,the applications of wavelike phenomena of the earth's interior to earthquake research is discussed, including seismic risk analysis and seismic zoning,earthquake prediction and seismogenesis researches.
Sopyright:China Earthquake Engineering Journal