Qin Baoyan , Wang Yucang , Wen Zhengping , Li Yarong
1994, 16(4):1-9.
Abstract:On the premise of studying the physics basis produced by unstability of source system,and according to the modulation model,we put forward the suggestion to make short term predic-tion using correlation between external agencies and frequency fluctuation intensification of small modulation earthquakes,we also suggest two indexes λ1,λ2 to discriminate the unstability of source system,the former is the unique factor modulation index,and the latter is multi-factor modulation index, or multi-factor modulation intensification index.The site prediction of strong earthquake should be decided according to the conjugate belt of small earthquake activi-ty in the stereoscopic model which appears immediately before earthquake and goes cross the future epicenter.
1994, 16(4):10-19.
Abstract:In this paper, for the two problems about the estimation of too many inversion parameters and the difficulties in calculating their partial derivatives in 2-D magnetotelluric inversion,based on the theories of rapid magnetotelluric inversion of 2-D continuous medium,the relati-vely rapid parameterized inverse method of 2-D layered model was realized by linearly approxi-mating the inverse object funtion of 2-D layered model and by using the weighting method to calculate their partial derivatives. The results of the inversion for theoretical models show that the inverse iteration can fit relatively rapidly and accurately the apparent resistivity and phase data,and make the obtained inverse model approach theoretical model.
Yang Liming , Guo Daqing , Shi Telin
1994, 16(4):20-24.
Abstract:The seismicity is characterized by the higher level in active period but the lower level in quiet for magnitude and frequency,and the interlace of these two periods.To study this mecha-nism,we used the exponential autoregression model which is originated from non-linear auto-vibration.The results show that the exponential autoregression model better reveals the preced-ing characters of seismicity,meanwhile the attenuation trend in this century is obtained.It is possible to expose the dynamical mechanism of earthquake according to the method of non-linear vibration.
1994, 16(4):25-28,36.
Abstract:In high confinig pressure,Bridgman effect makes fault slip easier. Therefore Bridgman ef-fect plays a role for helping earthquake to accur.
Several types of Bridgman effects induced by interaction between faults have been dis-cussed.Taking the 1931 Fuyun M=8 earthquake as an example,the role of Bridgman effect in earthquake occurrence has been discussed.
1994, 16(4):29-36.
Abstract:The repeated occurrence of time interval value is defined as temporal orderliness.Seismic activity(M≥7) in Xinjiang and nearby area possesses the temporal orderliness. 21 events(M≥7) since 1716 have occurred at intervals of 60,41,30,25 and 11 years. These values of orderli-ness can be used to predict the future M≥7 earthquakes.By using entropy and experiential dis-tribution function,we discuss the location and probability of the next strong earthquake. The result shows that there will be possibility of the occurrence of M≥7 earthquakes during 1996,2004 and 2015 in Xinjiang and nearby area.
1994, 16(4):37-41.
Abstract:This paper,describes the seismic velocity ratio anomaly of the Tuolai Ms 6.0 earthquake on October 26,1993,in middle-west section of Qilian Mountain.Hexi area,and discusses the medium-short prediction inedx. Based on the studies of Tuolai earthquake,it is considered that the region where the edge of the area concentrating lower value points of seismic velocity ratio intersects the seismic belt with lower velocity ratio anomaly value would be the location of future earthquake.Successively lower value anomaly of the seismic velocity ratio after several moderate earthquakes and obvious re-rising of velocity ratio value between 1 and 6 months before a stronger earthquake are taken as tendency anomaly and a short-term index to predict the stronger earthquake,respectively.
Ma Guifang , Sun Jialin , Yuan Xiaoling
1994, 16(4):42-46,53.
Abstract:Based on the analysis of a portion of the far-field(△=300-450km) precursory data before the Manlai M 6.1 earthquake occurring in Mongolia on Aug.31.1992,this paper puts forward that an anomaly group with regional concentration and time-domain quasi-synchro-nism will probably be a universalism character of medium-term and short-term precursors during earthquake-pregnant process and. based on this concept.makes a reseach On the three seismic factors of time,space and strength.
1994, 16(4):47-53.
Abstract:This paper discusses the systematic structure of seismically precursory information.points out the effect by which systematic structure gets information gain in systematic entirety and determines the matrix of systematic structure by using AHP method.The results from pracrical application in western Yunnan Province show that the structure has some positive significance in comprehensive earthquake prediction. MoreBack
Liu Baichi , Lu Taiyi , Yuan Daoyang , Liu Xiaofeng , He Wengui , Liu Jiansheng
1994, 16(4):54-62.
Abstract:The Quaternary strata in Laohushan area are mainly the torrenthial diluvium and river ter-race deposits,the ages of nearly 40 samples determined by14C,TL and diffusion equation meth-ods indicate that:the first terrace formed in Holocene, its age is about 4086±100a-4578±60a;the second terrace formed in late period of Late-Pleistocene,its age is about 23ka;the third terrace formed in early period of Late-Pleistocene,its age is about 72ka;the forth and fifth terraces formed in Middle-Pleistocene,their ages are about 217±35ka and 378±60ka,re-spectively. The deposits of Early-Pleistocene distribute only in some areas.perhaps formed in the early period of Early-Pleistocene.
By comparison with the loess profile at Jiuzhoutai of Lanzhou, the ages of I-V terraces are compatible with the ages of So,Sma,Smc,S2,S4 paleosoils in the standard profiles. The re-search results indicate that the formation of stratified landforms of rivers is associated with the tectonic movement,meanwhile,has a very closely inner relation to the global cold-warm alter-nation climate environment.
1994, 16(4):63-69.
Abstract:This paper introduced the seismicity and distribution of seismic lines along the northeast-ern margin of Qinghai-Xizang plateau and in its adjacent regions.There are 8 main seismic lines in the studied area. During different seismic activity period,the seismicity level of each seismic line is different.The results of study are advantageous to analyzing seismicity and fore-casting earthquake in this aera.
Wang Ruitian , Zhao Xianchao , Bi Guixiang
1994, 16(4):70-75.
Abstract:This paper deeply studies the distribution,natures and cause of geofractures associated with the Heze Ms 7.0 and Ms 6(3)/(4) earthquakes in 1937,and their relation to the active faults near the epicentral area based on previous studies and field investigations. Then the fracture pattern and the causative structures of the two earthquakes are discussed.It is considered thatthe fracture pattern of the Heze earthquake is conjugate fracture of double-shock type and the Chengwu-Dongming buried fault which trends form NW to SE is mainly causative structure of the Ms 7.0 earthquake.
1994, 16(4):76-80,84.
Abstract:Using Lyapunov exponent method and characteristic value method respectively,we dis-cuss and analyse the stability of linear viscoelastic dynamical system of deformation in this paper.Both linear and nonlinear evolution processes of dynamical system of deformation are imitated by computer with Runge-Kutta-Merson method.Some conclusions are physics basis in understanding the process of earthquake deformation.
1994, 16(4):81-84.
Abstract:1988年11月6日云南澜沧7.6级地震,仅次于1970年通海7.7级地震,是省内18年来发生的第二个大地震。根据震时地面地质考察,结合航片、卫片解释,发现黑河断裂带有突出的近代构造活动的地质、地貌及其它新活动特征,它对今后认识该地的地震危险性,可能会有所补益。
1994, 16(4):85-90.
Abstract:随着高精度的LCR-G型重力仪在流动重力测量中的广泛应用.用重力仪观测重力场随时间的变化,已成为探索地震预报的手段之一。由于LCR-G型重力仪监测到的是微伽级精度,因此,分析各种误差对它的干扰是非常重要的。
1994, 16(4):92-98.
Abstract:The Red River fault is one of the major regional active faults in China,it had been divided into the southern and northern segments according to the features of seismogeology,A new segmentation method,geochemical segmentation method,is introduced in this paper. Based on the features of densities. reservoir temperatures,circulating depths and concentrations of CO2,HCO2-,SO4- F,Li,Sr and B of the worm springs along the fault,the northern segment is further divided into four sub-segments,The seismic activities along these sub-segments of the fault differ from each other,which is thought to be mainly caused by the differences in weakness degree of each sub-segment due to the fluids in the fautl zone.
Sopyright:China Earthquake Engineering Journal