Abstract:This paper proposes the view that the width of source fault plane got saturated in seismogenic layer when the energy reaches certain threshold value. Based on the view, combining actual seismic data,the author draws the conclusion that the lower-limit magnitude of strong earthquake is 7.1 in Chinese Continent,and the thickness of seismogenic layer is 20km. In the condition of the same medium strength, the relative expression between source linear dimension and magnitude is derived in the case of different fault plane width. The research suggests that the width and length of source fault plane of shallow focus shock in China is complementary. As a result, it is a unified expression among the area Of-source fault,dislocation, seismic moment with magnitude (M=5-8.5).

Abstract:The stress drop and displacement during stick-slip under different normal stresses are measured in doublc.shear experiment. The coefficient of static and dynamic friction are obtained. The displacement-time curve during stick-slip is recorded by the instant wave recorder, then the seismic source time function is deduced, It's shape is similar to Brunet's time function,both decline as exponential function, it's Value is close to the site value measured in field. In order to make sure the experiment data reliable, the theory model of stick-slip is briefly analysed and calculated. The data obtained from laboratory, theory and field observation can be consistent with each other.

Abstract:This paper, raises two methods of distinguishing the seismic phase. By the greatest eigenvalue method, the arrival time of fast and. slow shear-wave and convert P wave may be determined. By the method of wave distinguishing factor,fast shear-wave arrival time and wave sequence may be determined. Combining these two methods, the possbility of taking the conversion P wave as fast shear-wave may be removed. By using the above-mentioned methods to 1983 Luquan Ms 6.1 earthquake, the results show that the fast shear-wave polarization direction is in keeping with what EDA hypothesis raised.

Abstract:To monitor the Arsenic dynamic variations in fault gases and groundwater, five spring points were located at the north segment of the Red River fault in western Yunnan. For three years, we have conducted Arsenic observation, the results show that Arsenic changes are fairly relaxed to the moderately strong earthquakes in this region. With the example showing the relations in the M 7.6 Lancing earthquake, the Arsenic abnormal features in the seismogenic process and the abnormal mechanism are discussed. And the feasibility of applying Arsenic in earthquake prediction also is demonstrated.

Abstract:Based on the characteristics of the earthquake sequences,the hypothesis of Cantor cutting of the seismogenic faults is introduced to study the frequency attenuation of the earthquake sequences and deduce the formula of frequency attenuation as
n(M, t)=F10^-bMt^-h

Abstract:In this paper, the data of the digital network in Zhangye district have been treated, and the Parameters of the events have been obtained. The spectral analysing for a part of events in Sunan has been made, the spectral parameters have been estimated. The source mechanisms and dislocating Parameters of the micro-events in Sunan have been converted using the method of amplitude ratio, the significance for tectonics and predietion have been discussed preliminarily. Finally, the advance work is suggested.

Abstract:The abnormal change of tilt data obtained by quartz pendulum tiltmenter at Wushi station before Ms 6.7 earthquake occurred near Yisaike Lake of Russia in Dec. 1990 and Ms 6.5 earthquake occurred in Keping of Xinjiang in Feb. 1991 were introduced in this paper. The order of accumulated anomaly of the Ms 6.7 earthquake was 1.3×10^-4,and its anomalous duration was two months. The order of accumulated anomaly of the Ms 6.5 earthquake was 8.5×10^-7, and its anomalous duration was 27 days. The prediction about the two quakes and the relationship between their deformation anomaly and, the geological structure were also analyzed and discussed.

Abstract:By analysing and comparing volume strain data with drawing crater data at Changping station in Beijing in 1990, this paper proved that the basic reason caused a big amplitude of short-term strain waves is the action of intermittent drawing water. As the change of water level is almost synchronous with the changes of volume strain, it is also valuable for the study on ground water level.

Abstract:In this paper, it was verified that the dynamic constitutive relationship of unsaturated undisturbed loess under random seismic loading still obeies a hyperbolic model by means of a dynamic tri-axial test system. But the parameters of the model are different from different time histories of applied random seismic loading. The contrasting research was made in parameters, shear, modulus and damping ratio under different random seismic loading and equivalent sinusoidal loading. The quantitative relationship between the parameters of the dynamic constitutive model and predominant period of applied random seismic loading was initially established. Through tests and computation, it was confirmed that Mansing Law is suitable for loess.

Abstract:Using four period large area vertical deformation data from 1972 to 1986 in Guanzhong basin and classical static adjustment method, the vertical displacement quantities and contours at various periods relative to 1972 are obtained,on which the change characteristics of vertical deformation field in recent years on Guanzhong region are determined. The results show that the recent vertical deformation of the crust in the region basically inherits the features of Quaternary, has slightly difference in the west of the basin. In addition,the stress field characteristics of the basin since 1972 are inversed by the finite element method through simplifying the basin to a plane model of mechanics, based on various background data such as geological investigation.

Abstract:This paper Studies the space-time prognosis of Xi'an ground fissures. Historic analysis method, Poisson Cycle model, Verhulst model and time series analysis were introduced to,predict the time regularity of Xi'an ground fissures. It is obtained that the long active period is 90-140 years long, the middle one is 10-14 years long and the short period is about one year. Information value method was used to analyse the space regularity, and the predicting precision is 81.6%.

Abstract:混沌是近几十年来自然科学的重大发现,它动摇了确定性预报科学的基础。于是气象学家放弃了数十天后的天气预报,地震学家在原来对地震预报的惧色上又增加了暗影。

Abstract:兰州地震研究所是国内最早开展大地电磁测深试验和研究工作的单位之一。

Abstract:对于1927年5月23日发生在古浪地区的8级大地震,前人已进行过调查研究,笔者也曾利用遥感资料对地震区内的构造环境进行了分析^[3]。

Abstract:From the geological point of view. the study area (Fig. 1) is mainly formed by the Hercynides and Alpides.