• Volume 9,Issue 4,1987 Table of Contents
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    • COMBINATION MODEL OF EARTHQUAKE DEVELOPMENT AND STOPPING PHASE IN SEISMOGRAMS-On the Rupture Process of the Tangshan Earthquake

      1987, 9(4):1-14.

      Abstract (604) HTML (0) PDF 935.04 K (542) Comment (0) Favorites

      Abstract:Firstly, this paper discussed the causal relationship between the combination model and stopping phase in seismograms. According to the combination model which was proposed by Guo Zhenjian et al in 1973, there are shear-stress concentration region, tension-stress abdicatation region and weaker medium abdication region at ends of accumulation element. When a rupture propagate from a stronger medium region into a weaker medium abdicatation region, the rupture will be speeded, then stopped quickly, thus stopping phase is produced. These termination factors are caused by the adjustment element of the combination model. The amplitude of stopping phase is related to abdication degree of the adjustment element. The better abdication degree, the more striking stopping phase.
      Secondly, this paper took the Tangshan earthquake of July 28, 1976 for example to study the stopping phase and rupture process. The result shows that the Tangshan earthquake is a bilateral rupture, total length is 96 km.

    • THE TEMPORAL FRACTAL STRUCTURE OF SMALL SEISMIC ACTIVITY BEFORE THE MENYUAN EARTHQUAKE(M=6.4)

      1987, 9(4):15-20.

      Abstract (517) HTML (0) PDF 438.41 K (533) Comment (0) Favorites

      Abstract:This paper, by means of the fractal method and fractal dimension D, studies preliminarily on the temporal fractal structure of seismic activity in the Menyuan area during 1970-1985. The result shows that there is D value and it changes from 0.58 to 0.42 before the Menyuan earthquake(M=6.4). It indicates that the temporal structure of seismic activity in this area trends forward more neterogeneows, i. e. the symmetry is broken or the ordering is strengthened, when the strong earthquake is more approaching to occur.
      The ordering has the characteristic of the multiple levels with self similar mosaic structures. It has not only the prediction meaning but also the theoretical meaning.

    • EXPERIMENTAL STUDY ON THE RELATION BETWEEN THE STRUCTURAL FORM OF FAULTS IN EARTHQUAKE SOURCE AND ITS STRESS ACCUMULATION PROCESS

      1987, 9(4):21-27.

      Abstract (497) HTML (0) PDF 494.83 K (801) Comment (0) Favorites

      Abstract:There are two combinatory structural forms of faults in the crust. The main faults of them(called the bottom faults)are respectively borne press stress and tention stress when the faults perpendicular to the main faults (called the vertical faults)creep or fracture. The former is called the Model P structure for short, the later the Model T structure. This paper has studied experimentally the effects when the vertical faults creep or fracture on the process of stress accumulation at the main faults and discussed the results with some phenomena in the seismic activity.
      1. When the vertical fault in the Model P structure creeps, the press stress perpendiuclar to the bottom fault increases, it can delay the occurrence of the main earthquake and increase the energy of this earthquake; In the Model T structure the press stress decreases and the shear stress on the bottom fault increases a little, it can urge the occurrence of the main earthquake.
      2. If a part of the vertical fault is a locked and healed fault or intact medium and when it fractures, it can suddenly increase the shear stress and decrease the press stress on the bottom fault in the Model P structure. So the larger foreshocks on this type of vertical fault can be considered a sign that the main earthquake on the bottom fault is coming.
      3.The experimental results under the condition that the unixal pressure or the displacement is constant indicate the stress accumulation process on the main earthquake fault.
      4. The fracture of main earthquake on the bottom fault can develop the aftershocks on the vertical fault and even causes great aftershocks.
      5. The phenomenon that the foreshocks of some earthquakes scatter on a belt has interpreted. It is helpful for deciding he fault plan of the main earthquake in the Model P structure.

    • OPTIMAL DISTANCE OF REDUCING SEISMIC RISK

      1987, 9(4):28-33.

      Abstract (548) HTML (0) PDF 400.01 K (793) Comment (0) Favorites

      Abstract:After a large earthquake took place, the accumulated stress and strain in focus and its neigborhood was released quite fully, so that the parallel faults in a certain range couldn't accumulate enough stress and strain to result in a large earthquake for some time. It means that a large earthquake has an effect of reducing seismic risk of in some distance for some time. So it is important to determine the distance and buration of reducing seismic risk. This paper, on the basis of the large earthquakes occurred in mainland of China, calculated the earthquake intervals for different length of time, From these statistial data the dominant interval and the optimal distance of reducing seismic risk were got. The dominant interval and the optimal distance of reducing seismic risk are inversely proportional to length of time. The distribution of earthquake intervals can be simulated by a normal probability function. Besides, the ground displacement at the distance of reducing seismic risk was given by the elastic dislocation theory.

    • THE B VALUE OF ACOUSTIC EMISSION IN FRICTIONAL SLIDING OF ROCKS

      1987, 9(4):34-38.

      Abstract (499) HTML (0) PDF 368.53 K (517) Comment (0) Favorites

      Abstract:The frictional experiments of rocks are made and the b value of acoustic emission is measured. The experiments show that the b value is stable and increases a little before stick-slip; but the b value keeps constant stick-slip and the b value increases with the increasing of the normal stress.

    • RESEARCH ON THE ALPHA TRACK ETCH METHOD AND ITS APPLICATION TO EARTHQUAKE PREDICTION

      1987, 9(4):39-47.

      Abstract (544) HTML (0) PDF 1.34 M (528) Comment (0) Favorites

      Abstract:Based on a large number of tests, some questions about alpha track etch method in cincluding the chemical etch of track, the juding of track, the couning of track, the source of error, etc. were discussed in this paper. In order to apply the method to earthquake prediction, some relevant stipulations were established. Correspondence between the method and the Longxi earthquake (M=3.6) was also discussed.

    • CHARACTERISTICS OF SURFACE TEXTURES OF QUARTZ GRAINS FROM FAULT GOUGE OF SOME ACTIVE FAULTS IN THE MINLE BASIN AND THEIR SEISMOGEOLOGICAL IMPLICATION

      1987, 9(4):48-54.

      Abstract (505) HTML (0) PDF 1.40 M (812) Comment (0) Favorites

      Abstract:In this paper we go into in detail the surface microtextures of quartz grain from fault gouge of three active fault in the Minle Basin, and discuss sliding behavior and relative ages of these faults based on the surface characteristics of quartz grains. Results indicate that the central segment of the Yingluoxia fault is in stick slip, but both its two ends are in creep slip. Paleoearthquakes located in the central segment of the fault (Heihekou) occurred approximately in the late pleistocene or early Holocene. The Cihu Fault in the region is recently active, its feature of stick slip is clear. It is presented that the old Qingshuigou Fault occurred in the Sinian period also was active during Holocene epoch.

    • VERTICAL DEEP-WELL ANTENNA-A NEWTYPE DEVICE FOR ELECTROMAGNETIC WAVE OBSERVATIONS AND THE PRELIMINARY RESULTS

      1987, 9(4):55-62.

      Abstract (553) HTML (0) PDF 564.52 K (706) Comment (0) Favorites

      Abstract:We have manufactured a multichannel reception device-the vertical deep-well antenna, which can be used synchronously with the antenna on the surface. In this paper, the principle and the structure of the device are introduced, At the same time, the preliminary results from observations since 1985 and the anomalous characteristics of electromagnetic waves before the four moderate earthquakes (magnitude larger than 5) occurred within 300 km range around the abservational site at Wuliduo, Kunming, during the period of observation are presented as well.

    • THE SIGNIFICANCE OF THE ENGINEERING GEOLOGY ON GROUND MICROTREMOR

      1987, 9(4):63-68.

      Abstract (440) HTML (0) PDF 434.85 K (1046) Comment (0) Favorites

      Abstract:There is a dispute about the principal character of the ground microtremor but it is universally accepted that the microtremor is controlled by the condition of soil character of surface of the site. On the other hand it is necessary to have a further study on how deep the soil structure is reflected from the ground microtremor and whether it can be used to identify the type of the site soil and its combination type, In this paper on the basis of observations of the ground microtremor of the cover layer of 400 to 900 m thick in Xian and the data from deep drilling, the following results have been achieved:
      1. The maid factor which makes an impact on the frequancy of the ground microtremor is the site soil layer structure and its combinational type;
      2. The depth affecting the first predominant frequancy of spectrum of the ground microtremor would be 120-190m;
      3. The different frequancy featurдs are associated with different sites and conbinational types of soil structure;
      4. The surface layer plays the main part in t5e impact on the frequancy of microtremor.
      In terms of experiments of explosions, it is seen that the soil structure can be damaged when the acceleration of the surface motion reaches. 1.0 g namely 10 degrees of intensity. The frequancy spectra of microtremor before and after explosions seems alike while the amplitude of microtremor after explosions descents and the peak value moves to the lower frequency end. Compared these results with the spectra of ground acceleration during the explosions, the three are extremely resemble. Similar features could be seen in the spectra of the strong ground motion recorded in Wenxian Station associated with a strong earthquake of M=7 in Songpan.

    • SEQUENCE ANALYSIS METHOD AND ITS APPLICATION IN EARTHQUAKE PREDICTION

      1987, 9(4):69-73.

      Abstract (481) HTML (0) PDF 297.11 K (730) Comment (0) Favorites

      Abstract:It is better to forecast the occurrence of an event by using pure-linear extrapolated method if the event is a stationary stochastic process. We are certain that the historical earthquake sequence is frequently non-stationary, but this non-stationary stochastic process can be transferred into stationary one by mathematical processing. We take the sequence of stress variation, that is the cube root of the released energy of an earthquake, 3E, as seismic sequence.
      In this paper, we forecast the seismic events of certain future period based on linear extrapolation of seismic sequences, which are M≥4.0 in Gansu province, M≥4.0 in the northern section of the North-South Seismic Zone and M≥7.0 in mainland China, respectively, using the expression of the reference 1:
      gN+1=a1gN+a2gN-1+a3gN-2+…+apgN-P+1
      And the result is satisfactory from the point of view of test.

    • BREIF ILLUSTRATION ON THE SEISMIC ZONING OF THE SEA AREA OF CHINA AND ITS VICINITY

      1987, 9(4):74-79.

      Abstract (583) HTML (0) PDF 259.48 K (447) Comment (0) Favorites

      Abstract:In 1986, the book of "countermeasure of earthquake" was published. In this book, it was pointed out that the countermeasure of earthquake in sea area have not been studied and need to study this problem in future. For studying the countermeasure in sea area, we have to compile a seismic intensity zoning of the sea area of China and its vicinity. We compiled this kind of map on the basis of earthquake activity, seismotectonics, topography and geophysical prospecting in sea area. The theoretical foundations of the compilation are described as follows.

    • >短文
    • ON WRITING THE ABSTRACT OF SEISMOLOGICAL JOURNAL PAPER FROM EXTRACT AND COMPILE OF THE ABSTRACT IN SEISMOLOGICAL LITERATURE SEARCHING SYSTEM——DISCUSSING WITH THE AUTHORS OF THE PAPER

      1987, 9(4):80-83.

      Abstract (495) HTML (0) PDF 321.36 K (516) Comment (0) Favorites

      Abstract:在计算机情报检索系统中,文献库存贮的是二次文献。二次文献是对原始文献进行分析、加工和整理后形成的。文献库数据文件中,文摘是每条记录最重要的内容之一。在地震学文献VAX计算机检索系统研制[1]过程中,作者参考了国外INSPEC文献磁带对中国地震学期刊论文文摘的摘编方法和国际标准ISO214-1976(E)[8]以及文献[2],对收录的期刊论文文献(英文)进行了处理加工(摘编)。

    • A PRELIMINARY STUDY ON THE BACKGROUND OF REGIONAL DEFORMATION OF THE MENYUAN EARTHQUAKE(M=6.4)

      1987, 9(4):84-87.

      Abstract (568) HTML (0) PDF 318.08 K (499) Comment (0) Favorites

      Abstract:1986年8月24日门源6.4级地震区及其附近,主要分布有四条总体呈北西西走向的大断裂(图1),即祁连山北缘断裂FD、肃南-老君山-冷龙岭断裂F1、清大坂-豹子崖-冷龙岭主峰断裂F2及属于北祁连构造带主干断裂之一的F3断裂,即昌马-俄博-古浪-海原巨型断裂带的组成部分。

    • RECENT STRUCTURAL ACTIVITY IN LINFEN BASIN

      1987, 9(4):88-90,83.

      Abstract (563) HTML (0) PDF 305.55 K (433) Comment (0) Favorites

      Abstract:临汾盆地位于山西省中南部,属山西断陷盆地之一,也是强震集中带,历史上曾发生过两次八级强震[1]。本文着重讨论临汾盆地地壳形变特征和近期断裂活动强度及其活动方式,为进一步研究临汾盆地近期地震危险性提供一些依据。

    • CHARACTERISTICS OF THE ELECTROMAGNETIC WAVE ANOMALIES BEFORE SEVERAL EARTHQUAKES

      1987, 9(4):91-93.

      Abstract (605) HTML (0) PDF 245.67 K (572) Comment (0) Favorites

      Abstract:据有关研究,震前辐射的电磁波频谱很宽,从超极低频到超高频都可能存在。因此,观测震前电磁波异常最好采用多频段接收方式。但是目前我们只能接收某频段的电磁波。

    • AN APPLICATION OF THE EXTREMAL VALUE THEORY TO THE SEISMIC RISK ANALYSIS OF SHANGHAI CITY

      1987, 9(4):94-97,76.

      Abstract (577) HTML (0) PDF 309.51 K (555) Comment (0) Favorites

      Abstract:极值理论在水文、海洋及地震中长期预报等研究中已得到广泛应用,但将它用于工程地震危险性分析则是近期才开始的。米尔内(W.G.Milne)和达文波特(A.G.Davenport)(1969)率先开展了这项工作,他们假定场地峰值加速度符合极值Ⅱ型分布,由此编制了加拿大地震区划图。Hattori(1979)用极值Ⅲ型分布对中国、中东等地进行了地震危险性分析。

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