Abstract:In this paper, according to the characters of wavefield propagation in medium and the multivariate statistical analysis, a ML criterion, which fits the data with the model is reached by strict mathematical derivation, is used to test whether the energy of specific wave type is present. The decomposed seismogram is obtained by using probability filtering, the arrived time can be find out from it directly. The technique is satisfactory for P waves, but is sometimes a little poor for S waves, which is probably due to the correlation between radial and transverse components. Especially for split shear waves, the arrival time obtained by this method, should be that of fast shear waves. Practical examples shown that the method is very available for the processing of three component recordings.

Abstract:This paper deals with a new principle of the dynamic-variable parameter-multi hierarchic method and its specific implement step in earthquake prediction. The variable parameter with time is considered in the method. The difference of the imitative value calculated by the method from reality is very small. One step-prediction by the method is identical with the reality in a few range of error. So this method is of certain applicable value.

Abstract:In this paper, we calculate the data of hourly values of Radon and Mercury of fault gas at Wushan by means of the optimal spectrum analysis method of tidal wave. The results show that semidiurnal and daily wave components which are consistent with the theoretical earth tide exist in hourly value sequence of Radon and Mercury content of fault gas. This proves that the change of Radon and Mercury content of fault gas can reflect the tidal stress and strain of crust. This conclusion gives the theoretical evidence of fault gas which is used in predicting earthquake.

Abstract:The fault systems of earthquake are non regular whether in laboratory test scale or in geologic scale, which have self similar structure. After a earthquake, the slip function of seismic fault reached the largest value in the middle segment of fault and reduced to the smallest value in two ends of it. The remainder strain caused by the mainshock was gradually adjusted by the faults of aftershock, which have different scales and different directions. The seismic fracture system formed by the mainshock and aftershocks has shown the fractal character.
Two structure models of foreshock and aftershock system have reported in this paper. Based on this result the non-balanced degree of seismic moment in a seismic fracture system has been defined. It is found that before some strong earthquakes the fractal dimension and the non-balanced degree of seismic moment show temporal and, spatial changes. The applying of fractal dimension and non-balanced degree of seismic moment in earthquake prediction are discussed.

Abstract:In this paper, b values of some seismic zones were calculated by means of modified magnitude-frequency relationship logN=b₁+b₂M+b₃M². The results show that modified magnitude-frequency relationship improved likelihood precision remarkablely. The residual of modified magnitude-frequency relationship was reduced 5.5 times maximally as against traditional G-R relationship. Upper magnitude of seismic zone was obtained conveniently. If there are enough time length data, obtained upper magnitude will rather satisfactory.

Abstract:The variations of the seismic velocity ratio before some reservoir-induced seismic events are studied synthetically, These seismic events include the Xinfengjiang Reservoir impounding earthquakes(M_s=6.1,5.3,4.5,4.4,4.4,4.3),the Longyangxia Reservoir impounding small swarm (M_L=2.5)in China, and the induced seismic events(M_L=2.7,2.5,2.0,2.3)at the Monticello Reservoir in the USA. The main results are:
(1) The V_p/V_s anomaly may be observed before the reservoir-induced seismic events in a wide magnitude range from M=2.0 to M>6.0;(2) The relationship between the precursory time △T and magnitude M of reservoir induced earthquakes shows clustering about a linear increase in lg△T with M, but the slope of the average line lg△T=aM+b for reservoir induced seismic events is remarkably smaller than that for natural tectonic earthquakes;
(3) The V_p/V_s anomalous area of a reservoir-induced seismic event is much smaller than the area of a natural tectonic earthquake, with the same magnitude.
The results obtained may be used to distinguish the reservoir-induced seismic event from the natural tectonic earthquake. An actual example is given.

Abstract:Based on C. A. Swanberg and P. Morgan's. empirical formula between temperature of silica equilibrium state in groundwater and practical earth heat flow data, this paper calculates the silica heat flow values in the northern segment of North-South Seismic Belt, and gives the outline of silica heat flow isogram of this region. The result shows that the silica heat flow as whole is middle normal value, and the high silica heat flow region is feeble anomaly. In addition, the relation between silica heat flow and tectonics is also discussed.

Abstract:This paper studied a mathematical method for separating sudden change anomalies from complicated background changes in earth-resistivity, and discussed how to recognize the sudden change anomalies in earth-resistivity due to earthquakes and sudden changes in interferences immidiately before the earthquakes taking the Jingtai earthquake (6.2) as an example. The result shows that for moderately strong or strong earthquakes which occur in the dense area of geoelectric stations, it seems to be possible to predict the epicenters and the times of occurrence using the method mentioned above immidiately before the earthquakes.

Abstract:This paper presents a general situation of medium-long term prediction on the 1991 earthquake of Ms7.6 in Burma. The main predicting bases are seismic gap, a Ms6.2 earthquake occurred on March 1,1989 two years before the Ms 7.6 earthquake, and a 300km long seismic zone formed quickly a month after the Ms 6.2 event, and synthetic analysis on situation of M≥7 earthquakes in a large area. The paper also emphatically discusses the relation between the seismic belt and coming great earthquakes.

Abstract:This paper introduced the measurements for three dimensional regional residual stresses, mosaic-residual stresses and their elastic strain energy densities distributing with depth in rock masses in measuring region of Xianshuihe fault zone, analyzed their plumb distributive regular pattern with depth, and computed the residual elastic strain energy stored in rock mass of this fault zone. In the measurement, based on orthotropic elastic theory of rock mass, the X-ray diffraction method is used, and the core specimens of 5 heavy caliber-boreholes are selected.

Abstract:This paper introduces the design thinking of telemetric seismic transmitting device with micropower loss, high-stability using high performance IC; design method of main units; main specification; and the calculation of main parameters.

Abstract:Based on the observation data of the earth microtremor in Quanzhou area, this paper discusses some important technical problems about observation and analysis of the earth microtremor, and studies the law of microtremor spectrum feature and the relationship between it and relative parameters in the site. Moreover, this paper also discusses the action of pulse predominant period in the site evaluation, the relationship between the period and shear wave velocities of soil layers and the concerned problems.

Abstract:In this paper, a far-ranging remote phenomenon of large earthquake activity(M_s≥7.0) has been discussed by seismicity time characteristics in China Mainland and its adjacent areas. Six zones have been divided with remote phenomenon, On the basis of giving remote phenomena in the paper, the active situation of large earthquakes Will be roughly estimated in research areas, and a useful reference for mid-range prediction of large earthquakes in one or two years in the future is got.

Abstract:在1992年出版的《未来灾害学》(郭增建、秦保燕、李革平著)中,首次提出了滑坡与泥石流的定级公式。其中有静力级和动力级两类。静力级是滑坡和泥石流体积的两次对数再乘10;动力级是滑坡和泥石流动能的两次对数再乘10。

Abstract:1990年4月26日,在青海省共-兴海之间发生了6.9级地震。震中位置为北纬36°07',东经100°08',震源深度约29公里,极震区位于共和盆地内,震中烈度9度,等震线长轴方向为北西向。初步判定共和盆地南缘北西向隐状断裂可能是该次地震的发震构造。

Abstract:1990年4月26日在青海共和-兴海之间发生了7.0级地震,微观震中为北纬36.1°,东经100.3°。本次地震发生在共和盆地西南缘。共和地区是历史上的少震区。值得注意的是震中东南为巨大的黄河龙羊峡水库,水库大坝距震中约50公里。

Abstract:对于大震前各种地震活动图象的变化特征,人们已经进行了大量的研究,但对于中等强度地震前小震活动图象的变化研究和总结较少。作者根据《地震学分析预报方法程式指南》^[1](以后简称"指南")中,有关孕震空区和地震活动条带的判定方法,研究了1980年以来甘肃省发生的7次中强以上地震前小震活动图象的变化特征,试图总结出一些具体指标,为判断地震趋势提供依据。

Abstract:A Ms 6.1 earthquake took place in the district nearby the city of Datong,Shanxi Province,in North China in October 1989.As this earthquake is the strongest one in North China since the Ms7.8 Tangshan earthquake in July 1976,this earthquake has drawn much attention.