• Volume 15,Issue 4,1993 Table of Contents
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    • A SEISMICITY MODEL AND ITS FRACTAL BEHAVIOR

      1993, 15(4):1-6.

      Abstract (599) HTML (0) PDF 360.64 K (569) Comment (0) Favorites

      Abstract:A hierarchy model simulating seismicity has been proposed, which can produce fractal characteristics of seismicity, such as Gutenberg-Richter relationship. Quantitative relation between fractal dimension D and b-value is obtained. The average epicenter distance between the earthquakes with magnitude m is derived by using the hierarchy model, which can be used to seek the potential earthquake regions.

    • AUTONOMOUS SYSTEM AND THE COMBINATION MODEL OF FORMING EARTHQUAKE SOURCE

      1993, 15(4):7-11.

      Abstract (554) HTML (0) PDF 352.66 K (904) Comment (0) Favorites

      Abstract:The concept of autonomous system in physics was firstly applied to the studies on seismogenesis and earthquake prediction. On this basis the authors have gone to further step to discuss autonomous system combining with the combination model. It is pointed out that for single seismogeinic body the adjusting elements may appear a characteristic of periodic movement before the occurrence of a great earthquake and form fluctuation aggravation of precursors. For large seismogenic system the time variation of seismicity of large area appears a certain periodic characteristic. The synchronization in autonomous system and some quantitative relations about oscillation period have been applied in generation of earthquakes. The theory of autonomous system and non-autonomous system are important for earthquake prediction.

    • ANALYSIS AND RESEARCH OF SqFOCUS POSITION OF THE MID-LOW LATITUDES IN CHINA

      1993, 15(4):12-22.

      Abstract (531) HTML (0) PDF 809.54 K (780) Comment (0) Favorites

      Abstract:Using the geomagnetic data of several great solar activities from Mar. 1988 to Mar. 1989 of 9 stations in China, and the equivalent ionosphere current systems of infinite plate current, we analysed the variation features of Sqfocus position of the mid-low latitudes in China and obtained reasonable explanation of Sqfocus variability corresponding to Kp, Dst, Apindexes. It is showed that 1) In different Kpindex intervals, Sqfocus has different regularities. When Kp<4, Sqfocus moves to high latitudes as Kpindex is increased; When 4p<6, Sqfocus moves to low latitudes as Kpindex is increased; when Kp>6, Sqfocus is indistinct as Kpindex is increased.2) Sqfocus variation along latitude direction was mainly caused by ring currents, but variation along longitudinal direction was mainly affected by IMF sector effect.

    • DISCUSSION ON THE SEISMIC TYPE OF THE LONGLING EARTHQUAKE AND SOME PROBLEMS CONCERNED

      1993, 15(4):23-29.

      Abstract (494) HTML (0) PDF 553.96 K (752) Comment (0) Favorites

      Abstract:According to the migration characteristics of three main shocks of the Long ling earthquake from the south to the north and the temporal-spacial zoning characteristics of sources based on the seismic activities of three main shocks and strong after shocks, the authors consider that the seismic type of the Longling earthquake is belong to a type of great ensuing earthquakes, i.e. the three main shocks are located on different sources respectively which link each other from the beginning and the end, and the three source regions have its fore-and after-shocks respectively. The reason why the Longling earthquake occurred in complete granite has been interpreted by stereo model and shear creep fault in deep, It has also been explained, forming multiple source when the main shock occurred and developing aftershocks because of the relative complete medium and the strong regional compress stress. A method to estimate magnitude of multiple source summing the length of each source fault has been advanced.

    • THE SPACE-TIME DISTRIBUTION FEATURES OF SHALLOW GEOTEMPERATURE ANOMALY IN THE BOUNDARY REGIONS BETWEEN QINGHAI AND GANSU PROVINCES BEFORE THE MENYUAN AND GONGHE EARTHQUAKES

      1993, 15(4):30-35.

      Abstract (574) HTML (0) PDF 412.42 K (593) Comment (0) Favorites

      Abstract:In this paper,the space-time distribution features of shallow geotemperature field in the boundary regions between Qinghai and Gansu Provinces during 1980-1990 before the Menyuan earthquake Ms=6.4 of 1986 and Gonghe earthquake Ms=7.0 of 1990 are studied.The main conclusions are as follows:
      In 1985,before the Menyuan earthquake,there appeared the shallow geotemperature rising, region,centered in Qinghai Lake,forming a elliptic area from Huangyuan to Mengyuan, and in 1986 the geotemperature value of the rising region decreased.From 1987,before, the Gonghe earthquake,there appeared, the rising region of shallow geotemperature with large and long time, concentrated in Huangyuan-Gonghe-Xinghai of Qinghai.In the region far from seismic centre,the geotemperature value went up early,and was small amplitude;nearby the epicenter,the geotemperature increasing was late but its amplitude was large.Immediately before the earthquakes,the shallow geotemperature showed undulating feature of sudden rising-sudden dropping.

    • THE CHARACTERISTICS OF ELECTROMAGNETIC WAVE ANOMALIES BEFORE Ms≥4.0 EARTHQUAKES IN GANSU PROVINCE AND ITS ADJACENT AREA

      1993, 15(4):36-44.

      Abstract (484) HTML (0) PDF 860.67 K (505) Comment (0) Favorites

      Abstract:Based on the observed data of electromagnetic wave of recent six years at 14 stations in Hexi corridor of Gansu Province, this paper analyses the characteristics of electromagnetic wave anomalies before 11 earthquakes (Ms≥4.0) occurred recently in Gansu province and its vicinities.The results show that the anomalous signal of electromagnetic wave mainly has two kinds:low-frequency pulse and paroxysmal pulse; The time appearing anomalous signal and intensity are related to magnitudes and epicentral distances. The greater the magnitude and the nearer the epicentral distance, the earlier the time appearing anomalous signaliis and the bigger the amplitude is; The anomalous signal of shallow earthquake is stronger, and appears pulse form; For deep earthquake the signal is weak relatively, and appears low-frequency pulsation.The anomalous signal shows a process of concentrated-calm-earthquake triggering.

    • THREE-DIMENSION INVERSION OF GRAVITATIONAL FIELD AND GEOIOGICAL EXPLANATION IN LANZHOU-TIANSHUI REGION

      1993, 15(4):45-51.

      Abstract (500) HTML (0) PDF 533.15 K (739) Comment (0) Favorites

      Abstract:Based on the result of deep seismic sounding and gravitational data, after makingtopographic correction for gravitational data and Mesozoic-Cenozoic deposition corrections, the deep structure of Lanzhou-Tianshui region. (E103°-107°, N33.5°-37°) was studied by using Parker-Oldenburg's 3-D inversion method of gravitational field. By synthesizing and analysing the geophysical and geological data of the region, it is pointed out that the region is a transitional belt of Qinghai-Xizang block, moreover, we think that that Longzhong basin is a fault block's structure one.

    • PATTERN RECOGNITION OF SITE TYPE

      1993, 15(4):52-60.

      Abstract (536) HTML (0) PDF 637.11 K (841) Comment (0) Favorites

      Abstract:By using the improved consecutive Hamming method, the site types in the Chengguan district of Lanzhou City and Zhangye area have been classified. The results show that it is feasible to classify site type using the method of pattern recognition. It not only improves the past empirical and macroscopic methods, but also makes it numeralization and computerization. The present method also increases the accuracy and velocity of recognition while improving the recognition ability. It is possible to comprehensively analyze, and pick up the various factors such as geology, topography, geomorphology, site soil features, etc, and to identify the site types quantitatively.

    • CONJUGATE EARTHQUAKE FRACTURE AND TECTONICS IN THE EASTERN PART OF NORTH CHINA

      1993, 15(4):61-68.

      Abstract (550) HTML (0) PDF 606.74 K (749) Comment (0) Favorites

      Abstract:The relation between earthquake and tectonics in the eastern part of North China was examined.The starting point of examination is to analyze the tectonic appearances in occurrence processes of the strong earthquakes. By the data of focal mechanisms, surface deformations, aftershocks, isoseismals and geodetic measurements for 5 strong earthquakes occurred in 1966-1976, it was found that the earthquake fractures appear as conjugate shear fractures with asymmetric amount.There is a predominant newbornness in the relation of earthquake fracture to tectonics.

    • CALCULATION OF IMMEDIATE PREDICTION PROBABILITY FOR LARGE EARTHQUAKE IN CHINA

      1993, 15(4):69-76.

      Abstract (487) HTML (0) PDF 483.90 K (864) Comment (0) Favorites

      Abstract:Using the immediate burst precursor of large shocks and the distributive character of their time interval, we have studied the variation with time of the probability of immediate earthquake occurrence. The results show that the predicative level of single precursor is very low, but for multiprecursor, the comprehensive probability is able to describe the change before earthquake and a better prediction can made using it The conclusions were verified taking the Tangshan earthquake as example.

    • ESTABLLSHING MODEL AND PREDICTION ON THE HIGHEST YEARLY MAGNITUDE SEQUENCE OF THE NORTH-SOUTH SEISMIC BELT

      1993, 15(4):77-81.

      Abstract (541) HTML (0) PDF 326.72 K (519) Comment (0) Favorites

      Abstract:In this paper, by using the basic idea of the method of dividing into groups in data handling proposed by A.G.Ivakhnenko, according to the way of creature-organism evolution, we have given a method which can select the best form and parameter of the model automatically and construct the higher order autoregression model. Using this method, a trial of establishing model and prediction on the highest yearly magnitude sequence of the North-South Seismic Belt is taken. And the highest magnitude of the North-South Seismic Belt is predicted in the future 5 years.

    • STUDY OF MAIN INFLUENCES ON FIXED-POINT OBSERVATION OF FAULT GASES

      1993, 15(4):82-89.

      Abstract (501) HTML (0) PDF 544.77 K (664) Comment (0) Favorites

      Abstract:In this paper, the continuous daily observational data for 2-3 years at 5 fault-gas observing sites in dry areas and the meteorological factors in the same period are treated relatively by using mathematics methods. The factors of influence on fault-gas observation are found out preliminarily. It is considered that the air temperature is the main factor. The mechanism of the air temperature influences on the escape of underground gases is also discussed.

    • APPLICATION OF GREY SYSTEM METHOD IN EARTHQU AKE PREDICTION

      1993, 15(4):90-95.

      Abstract (578) HTML (0) PDF 456.40 K (821) Comment (0) Favorites

      Abstract:In this paper, taking the origin times of earthquakes with different magnitudes, which occurred in different areas of North-South Seismic Belt as samples, the GM (1,1) building model method of the grey theory is used to build 13 prediction models.Using these models, the origin times of coming earthquakes have been predicted.The origin time of Guyuan M5.0 earthquake, Ningxia on Nov.2, 1989 was predicted betterly using the model with 5.0≤M≤5.9.

    • THE SEISMIC SCREEN IN THE NORTH CHINA BLOCK AND THE ATMOSPHERIC TEMPERATURE ANOMALIES

      1993, 15(4):96-101.

      Abstract (513) HTML (0) PDF 432.20 K (423) Comment (0) Favorites

      Abstract:This paper has made a study of the relationship between the seismic screen activities in the North China block area from 1966 to 1976 and the temporal-spatial evolution of temperature anomalies in the Greater North China from February 1960 to January 1977.The principal conclusions are:(1) The atmospheric temperature increment (February 1960, September 1975 and February 1976) and decrement (January 1977) in North China are related with the start and close of the seismic screen activities; (2) The individual earthquakes in the seismic screen and the atmospheric temperature incremen:concurred in certain temporal phases if the 16.5 years from February 1960 to July 28, 1976 when the M7.8 earthquake in Tangshan occurred is divided by 0.618N into 18 phases in time.

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