• Volume 5,Issue 4,1983 Table of Contents
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    • PRELIMINARY RESEARCH OF LOCAL EARTHQUAKE CODA MAGNITUDE

      1983, 5(4):1-11.

      Abstract (674) HTML (0) PDF 806.92 K (689) Comment (0) Favorites

      Abstract:The seismic coda wave of local earthquakes are composed of back scattering waves owing to numerous randomly distributed heterogeneities in the earth's crust. On this view, in consideration of linear relation between the seismic moment and the local Richter magnitude, a formula of the coda magnitude Mc is derived by using seismic coda of any lapse time, measured from the earthquake origin time. Its simplified form may be cinsistent with the relation of the duration magnitude M approximately. We may regard Mc that describes the size of the seismic moment of the focus as a generalized form of M. Hence a possible way is proposed for the explanation of the physical background for the duration magnitude.
      In Danjiangkou and its nearby regions a quality factor of coda wave, a function of the medium and a expectancy relation between the seismic moment and the local Richter magnitude are attained by applying to the data from the Danjiang Station. At the same time, we found a formula of the duration magnitude and a simplified formula of the coda magniude for the station.

    • SIGNAL EARTHQUAKE MIGRATION

      1983, 5(4):12-19.

      Abstract (551) HTML (0) PDF 633.04 K (447) Comment (0) Favorites

      Abstract:Studying earthquake migration has some significance for the earthquake prediction. In the earlier research, the earthquake migration could only be used in predicting its direction in stead of pointing out the earthquake region.
      In this paper, the author studied the seismicity before some strong earthquakes in China and found that the earthquake risk region may be determined by usingsignal earthquake migration. These signal earthquakes may be divided into two kinds:1. signal earthquakes occurred in the tectonic zones refuted to the tectonic junction region by targe earthquake. 2. signal earthquakes of repeat migration across seismic gap. Using these signal earthquakes we can roughly estimate where the earthquake risk region is.

    • ON JUDGING THE ANNUAL STRONG EARTHQUAKE HAZARD IN GANSU, NINGXIA, QINGHAI AND XINJIANG OF NORTH-WEST CHINA BY USING THE LOGICAL FUNCTION

      1983, 5(4):20-26.

      Abstract (580) HTML (0) PDF 548.31 K (569) Comment (0) Favorites

      Abstract:The logical algebra (Boolean algebra)has been widely used in a number of technical branchs. It is a pity that its application in earthquake prediction seems rare. So far as the research method on earthquake prediction is concerned, related to seismicity and its mechanical trigger factor is both quite widespread and noticeable, but it is still very difficult to apply the results obtained from abovementioned research concretely to earthquake prediction, because of the inregularity and complication in seismicity. The author tries to improve the results of abovementioned research by introducing the method of logical algebra. For this purpose, the general method for logical function which is adequate for earthquake prediction has been studied in this paper. As an instance for applying this method, selection 12 predicting foctors which consist of solar activities and seismicity on a global scale by means of the data in the period of A. D. 1914-1973, the predicting equation for logical algebra function to judge the annual strong earthquake hazard in continental crust in Gansu, Ningxia, Qinghai and Xinjiang of north-west China with magnitude Ms≥7 has been constructed. The historical coincident percentage for this equation in A. D. 1914-1973 is 100%, and the coincident percentage of the text of extrapolation in A. D. 1974-1982 is 88.9%, and this equation is useful for judging large background on annual earthquake situation in the abovementioned regions, This research indicates that the method of logical algebra function is one of hopeful methods concerning integrated earthquake prediction.

    • A PRELIMINARY STUDY OF FOCUS MECHANISM IN AREA OF GANSU HEXI

      1983, 5(4):27-32.

      Abstract (523) HTML (0) PDF 492.40 K (734) Comment (0) Favorites

      Abstract:In this paper the focus mechanism and stress field of the seismic activities in area Hexi is studied by using the method of the solution in the small compound earthquake. The result shows that there is a clear difference between the seismic upsurge period and seismic quiet period in the seismic area; and it may be used as an indication of seismic activities in the area.

    • ANALYSIS OF ANOMALOUS STATUS OF OIL WELLS IN THE VICINITY BEFORE AND AFTER THE MAGNITUDE 5.3 EARTHQUAKE OF LULONG

      1983, 5(4):33-39.

      Abstract (484) HTML (0) PDF 550.75 K (543) Comment (0) Favorites

      Abstract:The status of oil, water and gas in some oil wells in North China has been analysed. It is considered that there were immediate earthquake precursors prior to the magnitude 5.3 earthquake of Lulong. The anomalous variations were respectively initiated from two to five prior to earthquake in oil wells, such as well No.647 of Qikou, well No.11 and No.12 of Tanggu and well No.11 of Dazhongwang. The anomalous amplitude increased to 1-3 times higher than that of the normal background level. The sudden changes in which the amplitudes were even fifteen times higher than the level prior to shock, occurred half before the earthquake in the well No.18 of Tanggu. In the study the emergent mechanism for variations of oil, water and gas status is discussed. It is proposed that the best of observation procedure for examining the tectonic stress of the pusher type well is to datermine the pressure of the closed well.

    • ANALYSIS ON THE RELATIONSHIP BETWEEN THE WATER LEVEL IN A DEEP BOREHOLE AND ITS INFLUENCE FACTERS

      1983, 5(4):40-46.

      Abstract (598) HTML (0) PDF 538.77 K (787) Comment (0) Favorites

      Abstract:Based upon the reasonable calculatian of the some factors that can change the water level, the borehole data per hour during a period of 27 days in Yah zhou County, Shandong Province have been analysed by gradual regression method. The result was that influence of some factors on the water level has been better eliminated, and obtained the residual △(t) curves with random fluctuations, their mean error σ=6.97mm and complex correlation coefficient R=0.987. The mechanics process of the influence of some factors on the water level is preliminary discussed and some factors influence values are given Besides, by means of filtering analysis, the air-pressure data have been calculated, thus further understanding the assumption on air-pressure effect.

    • A STUDY ON TECTONIC MOVEMENT OF INTRAPLATE BLOCK AND GEOTHERM-EARTHQUAKE EFFECT IN FUJIAN, GUANGDONG AND JIANGXI

      1983, 5(4):47-59.

      Abstract (695) HTML (0) PDF 1.01 M (993) Comment (0) Favorites

      Abstract:Based on the experimental results of the thermal springs, the earthquakes, the structures, the distribution of magmatite and the thermal breaks, this paper states the characteristics of the geotherm field and discusses the relations between block movement and the Geotherm-Earthquake in Fujian, Guangdong and Jiangxi regions. The result of this study shows that the block differentiation actions are very strong in the regions since the Yanshan movement, it is closely related to the two important thermal stage actions (90 million to 120 million years from now and 157 million to 165 million years from now)in crustal deep. Modern thermal field is mainly the result of the geothermal stage action which continued to develop in Mesozoic Era. It is found that the front peak of magmatic action in Fujian-Guangdong tectonic zone had become Weak and backed obviously from ocean to inland in Cenozoic Era. But there remain the characteristics of block structure that cold block and thermal block alternated from northeast to southwest. The stronger the activities, the more remarkable the Geotherm-Earthquake Effect, and there was the characteristic that the activities gradually became stronger and stronger from inland to Taiwan.
      Analysing the ratio that the Geotherm-Earthquake energy in south Fujian-north Cuangdong block was depleted and disperred, we found that each of the blocks has specific DEPLETING-DISPERSING STRUCTURE, which is the thoroughfare that energy is transmitted and changed between the lower crust and upper mantle. It depends mainly on the foundation heat flow in upper mantle and the lateral nonuniformity. The energy flow of the Geotherm-Earthquake fakes about 2% of the geothermal flow of the ground.
      Applying the equifinal principle, we study the problem that tectonic force and thermal stress act unitedly on the preparation of intraplate earthquake and the breaking mechanism, and put forward that the end points and inflection points of the rhombic block circumference are the favourable locations, which cause easily thermal break. Therefore, it is possible that Manson-Coffin effect causes the thermal fatigue of the depth rock and elastic breakearthquake. Thus it may be inferred that to study the Geotherm-Earthquake structure is a new subject which has the theoretical and practical significance.

    • ON THE ACTIVE FAULT IN THE LOESS

      1983, 5(4):60-68.

      Abstract (545) HTML (0) PDF 808.33 K (826) Comment (0) Favorites

      Abstract:The loess covers the extensive areas in China, but tie active faults in the loess ahe often ignored. This paper systematically describes the various characteristics and the evolutionary processes of the loess faults. Together with a number of data in sedimentlogy, Geomorphology and Seismology, the author further divides the active faults of the loess into two types of different feature——the slow creep and the quick rupture. on estimating the trend of the future earthquake the later should be paid enough attention to.

    • >短文
    • THE FENGJIASHAN RESERVOIR EARTHQUAKES

      1983, 5(4):69-69.

      Abstract (799) HTML (0) PDF 134.41 K (444) Comment (0) Favorites

      Abstract:陕西宝鸡地区冯家山水库是一个小型水库。库坝为水石混合重力坝,坝高74米,库容量4亿立方米,1974年3月11日开始截流蓄水。当水位达到蓄水以来最高水位线706.11米时,在距大坝3-5公里的库区内连续发生了ML=0.5小震35次,尤其是在1975年10月2日11时至3日5时的19个小时内,竟发生小震达26次之多。

    • GEOPHYSICAL STUDY ON THE CRUST AND UPPER MANTLE STRUCTURE IN CHINA

      1983, 5(4):70-85.

      Abstract (573) HTML (0) PDF 1.05 M (469) Comment (0) Favorites

      Abstract:Crust and Upper mantle is the important place in which human beings live and obtain all sorts of resources, energy sources, transform and make use of the nature, and a place for the basic study of Geoscience,Since 1960s, the study of it develops rapidly. The physical exploration on the crust and Upper mantle of China's continent, costal area and transitional zones has a special position in the study of global plate tectonics and its driving mechanism.

    • RECENT TECTONICS AND SEISMIC ZONING IN NEW ZEALAND

      1983, 5(4):86-94.

      Abstract (646) HTML (0) PDF 600.48 K (573) Comment (0) Favorites

      Abstract:New Zealand is a country very prone to violent earth movements in the South Pacific Ocean. Active faults are distributed throughout the country. There have been 17 large earthquakes with M≥7 which occured in New Zealand since 1846. However, fault movement in various regions exhibits a great difference in size, features and intensity. In this paper, the size of active fault, the rate of horizontal and vertical crust movement since Late Quatarnary, the heat flow, the isostatic gravity and the velocity of Seismic wave beneath just the M-continuity, etc, in verious zones of New Zealand are introduced and compared. The characteristics of both recent tectonic movement and geophysical properties of the crust in different regions have been analysed briefly. From these, it leads to the result that 6 different tectonic zones cart be divided in New Zealand.
      The regional characteristics of seismic activities in each tectonic zone are also discussed, based on the historical and instrumental earthquake records in New Zealand from 1960-1980.

    • >报导
    • SYMPOSIUM ON GENESIS OF EARTHQUAKE IN LANZHOU

      1983, 5(4):94-94.

      Abstract (526) HTML (0) PDF 115.48 K (762) Comment (0) Favorites

      Abstract:中国地球物理学会于1983年8月20日至24日在兰州召开《地震成因》学术讨论会。来自全国各地的中国科学院、国家地震局所属研究所和有关高等院校代表90余名参加了会议,会上宣读了70余篇论文。中国地球物理学会理事长顾功叙做了书面发言。与会代表就地震成因方面近几年来在理论和实践上取得的研究成果做了生动的报告和热烈地讨论。

    • >短文
    • A METHOD FOR FURTHER STUDYING THE SEISMIC VELOCITY RATIO ANOMALIES

      1983, 5(4):95-98.

      Abstract (520) HTML (0) PDF 292.23 K (524) Comment (0) Favorites

      Abstract:A new method for studying the seismic velocity ratio anomalies was proposed. Its characteristics are:1). in the normal case the velocity ratio is a constant; 2). the anomalies are more obvious; 3). the data are added as many as possible, including those of earthquakes occurred in the boundary of the anomalous velocity ratio region, so that the information of the earthquake preparatory region can be provided in time. When the method is adopted to check the earthquake preparatory region in Gansu Province, better results have been obtained.

    • SOME IMMEDIATE ANOMALIES OF DEOPHYSICS AND GEOCHEMISTRY AROUND THE EPICENTER BEFORE TANGSHAN EARTHQUAKE

      1983, 5(4):99-102.

      Abstract (546) HTML (0) PDF 317.53 K (638) Comment (0) Favorites

      Abstract:Before Tangshan earthquake, magnitude 7.8 on July 28, 1976, many stations observing apparent electrical resistivity, ground water level and radon content in well water were set up within an area of radius 200km around the epicentre and the measurements were carried out for a long time at these stations.
      About 13 days (mainly within 10 days)before the occurence of Tangshan earthquake, the obvious sudden anomalies of the apparent resistivity, radon content and groundwater level were observed on a normal background at some stations. The stations that observed the anomalies were only a few, but they mainly concentrated near Changdong fault zone, the other stations at which the weaker anomalies were observed were located near Beijing area in the west of the epicenter.
      The comparison of these three sorts of anomalise shows that they are at the same temporal and spatial Characters.
      According to the fault plane solution of the Tangshan earthquake and investigation of Chang-dong fault and earthquake activities above magnitude 3 before Tangshan earthquake it can be seen that:The spatial distribution of the three immediate anomalies is in agreement with the fault plane solution of the Tangshan earthquake and Chang-dong fault and in agreement with the distribution of the earthquakes. At the same time, the obvious anomalies and weaker anomalies are in agreement with the earthquake zone of ML≥4 and the earthquake zone of ML≥3 respectively.
      In this paper it is believed that these anomalies may be the reflections of the process of the stress strengthening before the main earthquake.

    • >报导
    • TRACES OF THE ANCIENT EARTHQUAKES FOUND IN THE SOUTH JINGTAI OF GANSU PROVINCE

      1983, 5(4):103-103.

      Abstract (539) HTML (0) PDF 139.97 K (450) Comment (0) Favorites

      Abstract:为查清海原断层全新世活动特征,今年六月我们在景泰南三塘上东南约2公里处大沙沟(间歇性河流)横穿海原断层的地方,开挖了探槽。

    • OFFSETTING OF THE EARTHQUAKE RUPTURE ZONE AND HOLOCENE ACTION ON THE JINGTAI SECTION OF THE HAIYUAN EARTHQUAKE FAULT

      1983, 5(4):104-105.

      Abstract (589) HTML (0) PDF 212.46 K (438) Comment (0) Favorites

      Abstract:近年来,随着古地震学的掘起,遥测遥感技术和大比例尺航片判读的引进,微地貌,14C年龄和树轮年龄测定以及考古等方法的应用,地震地质学的地表工作有了突破性的发展。其标志是描述地震地质现象的时间尺度大大缩小,使得从数百万年的新构造运动尺度缩小为几万年,一万年乃至数百年的人文历史尺度,能够大体与地震区划和地震预报所要求的时间尺度相适应。

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