Abstract:By using various seismological anomalies obtained from the Meeting of National Seismological Consideration (MNSC) from 1988 to 1996,the relationship between the anomalies in a certain year and the earthquakes occurring in the Chinese mainland in the next year is studied.The data of 932 anomalies obtained by more than 46 prediction methods of the seismometry in the past nine years show that the number of the prediction methods of seismometry increased from 1988 to 1996.The corresponding ratios for different seismological anomalies with moderate or larger earthquakes are between 0 and 48%,the average value is about 28%,which is numerically equal to the corrective ratio of the forecasting regional number in Chinese earthquake prediction.The methods of the statistical prediction,the strengthening of regional stress field,the seismic bands,the modulation ratio of small earthquakes and the b-value have higher corresponding ratios with earthquakes,and the methods of the anomalous calm of seismic activity,the fractal dimension,the anomalous earthquake swarm,the c-value and the earthquake windows have lower corresponding ratios with earthquakes.The year when there is the highest forecasting ratio is 1989,and the year when there is the lowest forecasting ratio is 1990.As the same corrective ratio of the forecasting regional number,the corresponding ratio of seismological anomaly does not increase with time.The questions such as the physical meaning of every seismological prediction method and the inner relationship between the seismological anomaly and the earthquake,etc.will be studied further in the future.

Abstract:The three dimensional tectonophysics model of Holocene active faults is set up by using plentiful,reliable and quantitative data about surface active structures and seismometric data obtained from Qilian Mountains area.The movement features of active blocks in the area are described qualitatively or semi quantitatively.The transformation relation of movements among different blocks is explained.The characters of precursory anomalies and seismicities within different blocks are summed up.

Abstract:Time space evolution characteristics of medium term and short term precursors of the Heze M_S5.9 and Cangshan M_S5.2 earthquakes are analyzed and studied,and the generalities and individualities of the evolution characteristics are summarized.The scientific problems such as relation between seismic precursors and structures,relation between precursors from seismic source and tectonic stress field,relation between spatial distribution of anomalies and determination of site where earthquake will occur,relation btween temporal distribution of anomalies and determination of time when earthquake will occur,etc.are discussed.

Abstract:Proceeding from actual clustering of earthquakes,the primary characteristics,regularities and mechanism of earthquake clustering and fault interactions as well as their implication to earthquake prediction are discussed.Then the seismic hazard in the east Qilian Mountains is analyzed qualitatively.The occurrence of 1927 Gulang M_S8.0 earthquake deeply affects to the potential of future earthquakes on the faults in this region.It implies that:① future great earthquakes in the region will probably not occur until next earthquake clustering;② the occurrence of the Gulang earthquake increases the compressive stress on the Jinqianghe Maomaoshan fault zone which was believed to be most dangerous,thereby postponing the occurrence of the supposed great earthquake.

Abstract:Commensurable characteristics of activity of M_S ≥ 6 earthquakes in the southern Yellow Sea area since 1846 are analysed.There are major periods of 6 years,12 years and 57 years and periods of 63 years,69 years and 75 years besides in activity of strong earthquakes of the area.Based on commensurable and clustered characteristics of activity of strong earthquakes,the trend of strong earthquakes in the area in future is forecasted.The forecasting results are proved.

Abstract:Primary analysis and discussion on some typical earthquake precursor anomalies which appear in the range of 500 km are done according to the data recorded by the RZb-1 type digital strain gauge with high precision and broad channel.The results show that though there are some differences on the observed curve anomaly forms before the earthquake,there also exist some same characteristics such as solid tide distortion,strain rate increase,impending earthquake abrupt anomaly,strain step,etc.According to these characteristics,authors predicted the earthquakes,for example,the Hejing M_S5.7 earthquake on Feb.3,1993,the Ruoqiang M_S6.6 earthquake on Oct.2,1993 and the south Shaw an M_S 5.4 earthquake on Jan.9,1996.

Abstract:The conception of transient frequency and calculation method of wavelet packet are introduced,and time-frequency distribution about simulation and actual seismic signals is given.The results indicates that wavelet packet transform may be used to describe the characteristics of seismic signals at any moment and is worth applying to processing seismic signals.

Abstract:The problems of spatial-temporal distribution characters,the process of evolutionand its inhomogeneity of M_S ≥ 7.0 earthquakes in northern part area of Qinghai-Xizang Plateau have been studied.The results show that the active fields of moderate-strong earthquakes have some common features which have appeared before M_S ≥ 7.0 earthquakes,and have several stages in gestation process with different active abnormal phenomenon.These features can be used to judge the tendency and preparation stages,and have practice value for prediction of the events w ith M_S ≥ 7.0 in the area.

Abstract:In this paper,the authors briefly introduced the systematic structure,main functions,technical features and application scope of ‘geoelectricity softw are for earthquake prediction (GSEP)’,as well as its running environment,developing platform,technical index.The contents for further exploitation and spreading prospect are also discussed.

Abstract:Of the mechanical parameters of active faults,friction coefficient holds special importance in establishing the kinematic and dynamic relationships of active faults and in establishing the criteria of fault reslipping.Now,the friction coefficient is generally got from gouge test by using the double shear method.It is difficult to detemine whether the result from this test can reflect the real situation of the faults.So it is necessary to find out a new way for quantitatively determining the fault friction coefficient and its evolution.Based on theoretical study and practice,such a new method is put forward by using fault kinematic and dating data.

Abstract:The BP neural network is applied to predicting the potential of sand soil liquefaction.The mean diameter,relative density,standard penetration number and effective over burden pressure are selected as the indices.The forecasting results show that the method is feasible.

Abstract:Based on the systematical analyses calibration results of GS-15-216 gravimeter in base line field of gravity and the comparison between the results and the scale values provided by manufactory,it is shown that scale value of the gravimeter should be calibrated periodically because of its change with time,repairing instruments or changing work status would change the value and since scale value is a function of scale position,it must be calibrated one segment by one segment to fit a constant curve.

Abstract:Digital geoelectrical equipment controlled by microprocessor may be casually deadlocked or reset when measuring the apparent resistivity due to some interferences.Through careful analysis,it is found that the fundamental interferences are from pow er circuit and strong electromagne-tic filed,which reduce reliability of the equipment.Fortunately,the anti-interference capacity and reliability of the equipment could be evidently heightened by adopting software and hardw are improvement.

Abstract:The ways of thunder and light destroying seismostations are summarized.There was a light rod at Changping station,but it did not work well in protecting the station from thunder and light.The principle and advantages of a new device against thunder-bolt with capacity earth connection is introduced.The devices were installed at 42 stations in Beijing City and Fujian,Zhejiang,Sichuan,Liaoning,Guangxi,Guangdong,Hainan,Shaanxi,Hebei Provinces.Facts have proved that the devices are satisfactory.

Abstract:祁连山中东段的范围东起宁夏固原,西至青海祁连县以西的托莱山一带.该区曾发生过1920年海原8.6级地震,1927年古浪8.0级地震,近期还发生过一系列中强地震,如1986年门源6.4级、1990年景泰-天祝6.2级、1995年永登5.8级等地震.

Abstract:Based on results of tex tual research on histo rical data,location of Yijitanbao which had been destroyed during the 1125 Lanzhou M_S7 earthquake is determined.Analysing destroyed range of the event from historical data and site investigation,epicentral region of the event may be from Hekou,Bapanxia,Xigu to Ag anzhen where Loess landslips is densely distributed.

Abstract:The key of data communication is transmission of digital signal.The A/D transformation and D/A transformation can be carried out by using the MODEM.Process of V°4 interface is analysed.A brief introduction to the basic principle of the T-1496 MODEM is given.

Abstract:Based on the data of earthquakes (M_S ≥ 7),earthquake deformation zones,active faults and active tectonic system in nor theastern Qinghai-Xizang Plateau,combined with the theories and methods of the earth system science,geological mechanics,seismogeology and modern seismology,the ‘commonness’ of the strong earthquakes in the region is discussed.A new concept,named as contemporary tectonic deformation system of the regional crust characterized by three dimensional dynamics is pro posed.A new cognition on the mechanism and distribution of the earthquakes in the region is presented.

Abstract:In the paper,some analyses about the failure of rocks are made.It is suggested that earthquakes are actually the instability of nonlinear system,and that load-unload response ratio (LU RR) reflects the closeness of rocks to the peak of stress and marks the danger level of some earthquake prone areas.It is found that the difficulty of impending earthquake prediction happens after the peak of stress.The possibility of impending earthquake prediction is also discussed.