• Volume 7,Issue 2,1985 Table of Contents
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    • THE MODERATE EARTHQUAKE BEFORE LARGE SONGPAN EARTHQUAKE IN 1976

      1985, 7(2):1-7.

      Abstract (553) HTML (0) PDF 502.23 K (505) Comment (0) Favorites

      Abstract:In August 1976, the strong earthquakes with Ms=7.2,6. 7 and 7.2 respectively occurred in Songpan-Pingwu, Sichuan Province, which is the largest event in the middle section of the north-south earthquake belt in China since 1933. A series of moderate earthquakes of magnisitudes 5.0-6.5 occurred here during 1933-1976. This Paper deals with the characteristics of the moderate earthquakes, such as: shock in epicenter, the release of seismic energy, the change of small shock frequency in focus region, epicenter distribution as well as magnitude attenuation of the aftershoks. It suggests that moderate seismicity during 1973-1974 should be the precursor of songpan-Pingwu earthquake in 1976. we can separate them from commom ones based on their features mentioned above. The significant characteristics can be regarded as: from 1972, the release of seismic energy had assumed a striking contrast between focus region and its surrounding region, a reversal past proportional change relation: The epicenter diffusion of aftershocks of these moderate events couldn't be seen; on the contrary, the main shocks were very clear. The durations between moderate earthquakes and their own largest aftershocks lasted over 4 days, not only in near regions but also in many other areas. In early 1976, i. e. half a year before largeearthquakes, an abnormal seismic quiet had been kept in the region till their occurence.
      Besides, combinating with the migrating feature of historical large earthquakes in these regions, it is possible to prereveal the location and time of Songpan-Pingwu earthquakes in 1976. The preparing process of the shocks seemed to be divided into stages by 1949, 1972 and early 1976 respective 17.

    • PREDICTIVE IMPORTANCE OF THE SHENWO EARTHQUAKE TO THE HAICHENE GREAT EARTHQUAKE

      1985, 7(2):8-13.

      Abstract (647) HTML (0) PDF 420.31 K (767) Comment (0) Favorites

      Abstract:The earthquake (m=5.2)occurred in Shenwo reservoir region in Liaoning Province on Dec.22, 1974. In this paper by analysing its status of the event in the regional seismicity before and after the Haicheng earthpuake (m=7.3), measuring amplitude ratio of P, S waves and half of the period of first p arrivals, it has shown that the action form of tectonic stress and its concentrative level in Shenwo region were unchanged before and after the largest earthpuakes among this seismic sequence and it was after the Haicheng earthquake that great change took place to them.
      The authors believe while monitoring the temporal spatial variation of seismicity in the extensive area, we should notice that a larger earthquake could occur in the vicinity if the seismological parameters such as amplitude ratio(the action form of tectonic stress)and half of the period of first p arrivals(seismic stress drop and concentrative level of tectonic stress) were unchanged before and after the largest earthquake in a moderate seismic sequence.

    • THE VARIATION OF ROCK SUSCEPTIBILITY WITH UNIAXIAL PRESSURE

      1985, 7(2):14-22.

      Abstract (415) HTML (0) PDF 568.56 K (720) Comment (0) Favorites

      Abstract:The piezomagnetic curve under uniaxial pressure has been measured by inducing method to the five kinds of strong magnetic pyrogenetic rocks in Beijing-Tangshan region. It has been found out in the test that the curve may be divided into two different morphological phases. The curve of piezomagnetism rises when the pressure is exerted on it in the iniatial stage, and then it falls straight at an invariant speed. There exists a certain relationship between the curve form, the kind of rock specimen and the number of circulation. The variation of piezomagnetic coefficient is-(0.9-3.0) ×10-4cm2/kg. on an average magnetic susceptibility decreases 20-30 per cent from the beginning of pressurization to the rock destruction. It has been discovered as well that there does not exist a clear relationship between the variation of susceptibility and volume expansion of rock.
      This paper gives a preliminary explanation to the piezomagnetic curve mentioned above with the theory of magnetic domain in ferromagnetism.

    • Q ESTIMATES IN THE NORTH OF NINGXIA AND ITS NEIGHBOURHOOD with THE CODA OF OVERLOADED RECORD OF LOCAL EARTHQUAKES

      1985, 7(2):23-30.

      Abstract (545) HTML (0) PDF 504.22 K (825) Comment (0) Favorites

      Abstract:On the basis of Akis theory of coda, this paper develops a new method to estimate Q-Value for the upper crust medium with the coda data of the overload seismogram recorded by single station with this method, and distributions of Q-value in North Ningxia(38°-41.5N, 104°-107°E)are determined. The results point out that Q-value in Yin Chuan graden between Wuzhong and shizuishan(Q-value 100-200)is clearly lower than that in neighbouring Alashanzuo Banner and Dengko(Q-value: 200-300), and there are anomalous regions of Q-valne in the partial zomes. Finally, the obtained results are discussed.

    • RESEARCH ON SOME CHARACTERISTICS OF THE SEISMIC CODA

      1985, 7(2):31-39.

      Abstract (624) HTML (0) PDF 567.25 K (867) Comment (0) Favorites

      Abstract:Based on studying seismic coda characteristics of both artificial and natural sources, we have discussed the coda amplitude decline, the coda frequency and the other parameter Q1, which change as time goes by.
      The results indicate that the different parameters α, K, Q get identity of variation. Comparing the results from seismic source and from the experiment, we believe that they are similar to each other So it is possible to carry some prophetic Information in some parameters ofco da defore an earthpuake occurs.
      we will improve our work in future.

    • EXPERIMENTAL STUDY ON THE TECHNIQUE OF CALIBRATION OF THE INSTRUMENT FOR MEASURING RADON IN WATER BY THE SCINTILLATION METHOD

      1985, 7(2):40-49.

      Abstract (501) HTML (0) PDF 660.50 K (880) Comment (0) Favorites

      Abstract:This paper is a report which systematically summarizes the experiments on the technique of calibration in the instrument for measuring radon in water by scintillation method. The following aspects are involved in this study:
      1. The selection of the standard radio-active souree of radium in calibration.
      2. The inspection and regulation of the instrument.
      3. The sealing time for accumulating radon of the liquid source.
      4. The time for expelling radon before sealing.
      5. The background value of radio activity in the counting sell.
      6. The volume of standard source.
      7. The volume and shape of the diffusion bottle (used for collecting the samples of radon in water)
      8. The time interval between two consecative calibrations in the scintillation sell, and the live time of the sell.
      9. The suggestion on setting up the standard source in the level of the provicne, which is more superior than that used in the stations.

    • ANALYSIS OF ABNORMAL FEATURES TO THE DYNAMIC STATE OF GROUNDWATER BEFORE SOME EARTHQUAKES IN XINJIANG REGION

      1985, 7(2):50-57.

      Abstract (449) HTML (0) PDF 504.36 K (555) Comment (0) Favorites

      Abstract:In this paper the authors have rearranged and analysed the data of groundwater level and some oil wells in Xinjiang Region and discussed the abnormalfeatures of groundwater dynamic state before moderate strong earthquakes. We think that in this region the short-term and imminent precursors of groundwater level are conspicuous. But such anomalies can only be observed in the limited area close to the anomalies of earthquake source, and they are roughly divided into twot ypes, the descending and the spouting Afew problems relating to the groundwater in the process of earthquake preparing are under discussion as well.

    • PRELIMINARY ANALYSIS AND STUDY ON THE MACROSCOPIC PRECURSORS OF LANDSLIDE

      1985, 7(2):58-63.

      Abstract (529) HTML (0) PDF 449.58 K (765) Comment (0) Favorites

      Abstract:The field investigation has told us that a series of macroscopic precursors and anomalous phenomena suddenly arise before many of large-middle scale landslides happen. In this paper, to forecast both the time and the probobility of the occurrence of large-middle scale landslides is discussed by analysing and studying the precursors and the anomolies, their temporal-spatial distribution and their physical mechanism. Results of priminary study are:
      1. The occurring of most of large-middle scale landslides is companied, before theevents with macroscopic precursors and some particular anomalous phenomena which are of obviously temporal-spatial distribution and characteristics of some sequences.
      2. Accoding to the relationship between the macroscopic precursors (or anomolies)and the motion of the slide-body, the author has raised several macroscopic symbles and anomalous messages which appear close to the time when major slide of large-middle scale landslides occurs.
      3. The result shows that it seems probable to forecast and pre-dict the occurring of large-middle scale landslides, and to identify the stability and the slide tendency of the slide-body according to these symbles and messages.
      4. In addition, it has been also discussed how to distinguish the macroscopic precursors of both landslide and earthquake.

    • STUDY ON THE CONDITIONS OF THE STATION LOCATION OF TELLURIC CURRENT IN GANSU PROVINCE

      1985, 7(2):64-76.

      Abstract (473) HTML (0) PDF 926.17 K (1033) Comment (0) Favorites

      Abstract:The lithologic character conditions of 15 telluric curreng stations in Gansu Province are focussed to be analysed and discussed in this paper, so are the tectum and the influecnce from its thickness, the conditions of hydrogeology and telluric current.A superficial analysis is made about the influence on the resistivity from temperature with a view of physics mechanism. We consider it an effective mtehod in earthquake prediction that the variation of the resistivity at the depth of hypocenter monitored at regular intervals dy electrical sounding can tell us the variation of the temperature in earthquake source. With the help of the colleagues, the author has done the work of ortho-electrical sounding in most of the stations in Gansu Province. Meanwhile focal point of this work is to make the electrical measuring profile in the previous pole regions of Jiayuguan station and it is explained that why the abnormal relationship can be built between the annual variation of resistivity of the previous pole lines at this station and the morphogenesis of underground water.To verify and confirm the aboved-mentioned conditions of the station location, it is necessary in this paper for 258 earthquakes occurred near the station for years to be counted up and for the relationship between these shocks and the amomalies of resistivity to be analysed. A synthetic comment is presented here on the favourable and unfavourable conditions of the station location in Gansu Province.

    • THE PRELIMINARY STUDY OF THE RELATION BETWEEN CRUST AND TOP STRUCTURE OF UPPER MANTLE IN SEVERAL LARGE EARTHQUAKE AREAS IN CHINA

      1985, 7(2):77-84.

      Abstract (616) HTML (0) PDF 550.23 K (796) Comment (0) Favorites

      Abstract:Based on the crust structure in China and its vicinity areas, especially background of deep crust structure where some large earthquakes took place in recent years, this paper discusses the possible structure model for the occurrence of earthquakes.
      The results show that all modern seismicity occurred in the places where the thickness of crust changed rapidly or the structure twisted; Moreover, in these areas shocks would exist on the slopes or fringes of lifting parts of top upper mantle and other lifting areas nearly. In these spots the stress easily accumulates and breaks take place frequently.
      This is the deep structure background of occurrence of earthquakes Furthermore, the areas where deep earthquakes take place are closely related to the high gradient variation of gravity field, magnetic field, and to low resistance layers, low and high velocity layers.
      This kind of relation between earthquakes and deep geological structure as well as features of geophysical fields must be envisaged in the earthquakes prediction and in searching for their origin.

    • THE APPLICATION OF FIBER OPTIC COMMUNICATION TO THE COMPUTER SYSTEM

      1985, 7(2):85-88.

      Abstract (499) HTML (0) PDF 260.01 K (1029) Comment (0) Favorites

      Abstract:The paper describes the Fiber Optics Communication in the microcomputer closed loop control system for our work. It contains the circuits of serial emitter and receiver, in which the baud rate may be adjusted over zero to 25ok bit/s, as well as the circuits of the encoder and decoder for both syschronous and data information.

    • DISCUSSION ON EARTHQUAKE PREDICTION FROM THE STEREOGRAPHIC CROSS MODEL

      1985, 7(2):89-94.

      Abstract (484) HTML (0) PDF 397.64 K (730) Comment (0) Favorites

      Abstract:1983年作者在昆明举行的南北地震带会议上提出了立交模式。1985年正式发表(本刊)。本文是上一篇文章的继续,重点讨论了以下的问题。
      1.把立交模式应用于解释远距离的大震迁移,具体讨论了横穿青藏高原和鄂尔多斯地台的大震短期迁移现象。这种远距离跨越大地构造单元的震中迁移已往是很难理解的,但是从立交模式来看,则是很自然的。
      2.由于下岩石圈近于塑性,且相对均匀,所以在大区域构造压力作用下,其内形成的剪切滑移线与区域压力成45°角,因之如果己知若干地震排成一条线则可认为与其相交45°角的方向就是主压应力方向,这可与震源机制所求得的P轴方向相互补证。依此方法对华南和甘青地区的主压应力方向作了推求。
      3.在用相距较远的地震连直线的时候,对于中等强度的地震至少得三个地震连直线,对大震来说,两个即可。这是因为大震的断层面通入地下深,直接受到下岩石圈中蠕滑断层的影响。而中等强度的地震的震源断层面如插入地下浅时,则不直接受这个蠕滑断层的影响,因之取两震连线难排除偶然性。如三震相连则可能是深部蠕滑断层共同制约,不然为何在短时间电它们连成一条线。
      4.如果已知区域主压应力方向(用一些大震震源机制所求P轴方向的平均或用其他方法求得),则当一处发生大震后,可通过震中作与主压应力方向成45°夹角的直线,此直线即为今后震中迁移的较可能的方向,这个直线有时与已发地震的断层走向一致。
      5.一些外因,如固体潮和极移等有可能影响下岩石圈中蠕滑断层的动态,並由此影响上岩石圈中大震的发生。这是调制模式的另一种形式,即外因对震源的间接调制。
      6.我国震中迁移的事实表明,历史上短期震中迁移的始发地区可能是一个前兆穴位。在该区选择良好观测台址进行前兆观测可监视较大范围内的大震发生,特别是监视历史上震中迁移方向上今后再发生的大震。

    • >研究报导
    • ACTIVITIES AND EARTHQUAKES OF LANZHOU JINCHENGGUAN FAULT SINCE HOLOCENE EPOCH

      1985, 7(2):95-98.

      Abstract (477) HTML (0) PDF 344.54 K (423) Comment (0) Favorites

      Abstract:金城关断裂位于兰州市黄河谷地北缘,是兰州地区规模较大的断裂之一,中、新生代以来,对兰州市黄河谷地的形成、发展及其演变过程,对兰州地区的地震活动都起着重要的作用。

    • THE CHARACTERISTICS OF SAND VEIN AND SAND VOLCANO AND THEIR IMPORTANCE TO EARTHQUAKE

      1985, 7(2):99-103.

      Abstract (561) HTML (0) PDF 381.31 K (437) Comment (0) Favorites

      Abstract:沙脉和沙火山不是一种罕见的地质现象,在国外早有报导和研究。近十几年来,在我国,由于地震地质研究的不断深入,沙脉、沙火山屡有发现,本文就其特征及与地震的关系作一初步探讨。

    • GEOMAGNETIC ANOMALIES BEFORE THE WUNANSHA EARTHQUAKE (M=6.2) IN THE SOUTH OF THE HUANGHAI SEA

      1985, 7(2):104-105.

      Abstract (666) HTML (0) PDF 132.23 K (625) Comment (0) Favorites

      Abstract:1984年5月21日在江苏省东南部海域南黄海的勿南沙一带(北纬32.7°,东经121.7°)发生了6.2级地震。震前一个月以内,地磁低点位移平面图、幅相法在华北南部出现较明显异常。据此曾对该地震做了一定程度的预报。

    • THE DISCUSSION ON HEAT-FRACTURE MODEL

      1985, 7(2):106-108.

      Abstract (552) HTML (0) PDF 242.18 K (453) Comment (0) Favorites

      Abstract:任何解释地震发生过程的模式,必须要能说明各种与孕震有关的前兆观象。目前,膨胀-扩散模式在解释波速比的变化方面是比较成功的,但是对地壳的各种类型的形变、地温的变化、震源机制解中主压应力轴的转向或变化、发震构造型式等都不能在此模式中求得答案,因此,有必要提出更合理的模式来解释上述现象。

    • THE STANDARDIZED CURRENT OF AUTOMATIC TIME-SEQUENCE-CONTROLLED VIBRATION PICK-UP WITH ZZD PERIOD

      1985, 7(2):109-111.

      Abstract (619) HTML (0) PDF 224.44 K (694) Comment (0) Favorites

      Abstract:在整个传输系统中,由输入到输出是在一定的动态精度下工作的。为了对有线遥测传输、无线遥测传输、有线短中长距离直接传输等进行系统的幅频特性监视和维修,采用低功耗CMOS集成电路设计了长周期、中长(强)周期、短周期拾震器三分向时间程序自动控制标定电路。

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