1987, 9(1):1-9.
Abstract:This Paper continues to 《The Non-Linear Stage for the complex Focus System and the Prediction of Large Earthquakes》[1]. By means of the fractor in contemporary statistics physics,[2][3]the paper deals with the Similar unlimited mosaic properties of the different stratification planes and the multiple levels of non-linear stage for the complex focus system. From this, according to the acceleration of the obvious creep in seismometry, the first non-linear layer is obtained, and every layer can be calculated, The certain non-linear time interval is:
T2(a)=T2(1)/Ca,n=1、2、3…
where C is the ratio between T, the time of earthquake preparation in some area and T2[1], the non-linear time interval of the first layet. This is a statistical quantity. The statistics of the document[1] shows that as to the large earthquakes in different areas, C value is fixed at about 5. The ratio of every non-linear layet and the accompanied precursary abnormalities of unstability obtained according to the above formula, can give a definite prediction of earthquake for moderate and short terms.
1987, 9(1):10-17.
Abstract:In this paper, the relationship between the regularity of spatialtemporal distribution of great earthquakes in Southwestern China and the force source has been discussed. It has been divided into three different kinds:i. e. A, it is related to the frontal collision along plate boundaries. The epicenters are distributed in the interior part of Asia continent and the activity order A is taken to be finished. B, it is related to the increment and adjustment of tectonic stress field caused by the relative motion of intraplate blocks such as the Sichuan-Yunnan rhombic block. The activity order B in this period is taken to be finished as a whole, except some unclear localities. C, it is related to a shear-push action along the Andaman-Burma suture line, resulting in earthquakes in Southwestern Yunnan in a shorter period of several years. This kind of force source can cause the quickest reaction in the internal part of a plate.
Shao Shiqin , Zhang Cheng , Deng Qizang
1987, 9(1):18-25.
Abstract:This Paper discusses how to calculate the travel time of nearby-seismic wave, gives out the four kinds of equations of time interval of near-by seismic wave for the interval mutiple-layer crust model, deals with the theoretical time-interval equations and their solution ways, obtains the experience and the methods of time interval curve for the fitting observation, designs the solution of the theoretical time interval equations as well as the fitting observationary curve and the calculation program in making the table.
Zhang Bi'ao , Dong Zhiping , Han Youzhen
1987, 9(1):26-32.
Abstract:This paper deals with the features of geothermal field in the investigated area. By means of the data of 38 geothermal gradient and their calculated heat flow values, Curie isothermal surface has been calculated. The results are:
1. The mean geothermal gradient in this investigated area is 3.2c/100m; and the mean heat flow value is 1.52 HFU.
2. The depth of Curie isothermal surface in the different regions changes from 14 km to 34 km below sea level. In the belt of Curie isothermal gradient occurred strong earthquakes principally. Finally the preliminary study was done on the relationship between geothermal field and the occurrence of earthquakes.
1987, 9(1):33-41.
Abstract:On theoretical investigation of the literature[1], the propagation characteristics of long-period seismic and deformation waves that are produced by indefinite plane sliding in rheology medium, and the time-space distribution of complex patterns at two special frequency bands of three displacement models for source are quantitatively calculated.
In addition, the dependences of Comyzlep patterns on other parameters are explored.
These results can be used for analysing the slow earthquake and some precursors of short-term and imminent earthquake.
1987, 9(1):42-47.
Abstract:At 4:45 on Sept. 12, 1985, 20 days later after Wuqia earthquake(Ms=7.4), a strong aftershock of Ms=6.7 occurred. A violent seismic accelerograph recorded its waves about 4 kilometers to the epicenter which was determined by the seismograph network. The maximum acceleration of its eastwest component is 123.8 gal, which is four times greater than its vertical component. The corresponding period of the acceleration peak value of the response spectrum of this earthquake is longer than those in Heicheng, Tangshan and Songpan. The intensity of the earthquake motion near the epicenter is equal to 7, but its real failure is only 6.
1987, 9(1):48-53.
Abstract:One type of the seismomagnetic effects is represented,——oscillatory geomaglletic abnormality before some earthquakes. Based on the inclusion model a possible physical mechanism of above seismomagnetic effect is represented as well.
When the inclusion is in instable stage there are lots of microcracks in it, if there are fluid surrounding the inclusion, dilatancy that occurs more rapidly than fluid can diffuse into the newly created pore space, which can reduce the pore fluid pressure. A decrease of pore fluid pressure increases the effective compressive stress, and the inclusion will be hardening when fluid diffuses from surrounding material into the inclusion, the pore fluid pressure increases total compressive stress decreases, and the inclusion is weakened and is instability again. According to the theory of fluid diffusion of magnetic effect, the oscillatory seismomagnetic effect will cause this process. Finally, the reasons of different types of oscillatory seismo magnetic effect are discussed.
Zhang Yunlin , Si Yulan , Guo Shounian , An Haijing
1987, 9(1):54-61.
Abstract:This paper deals with the results of repeated observations in apparent resistivity on Ebo site, Qilian, Qinghai Province from 1979 to 1985 by of MT method. It is suggested that the observationary site is characterized by low noise background and high seismicity around it. During the observation the stability of the instrument was kept very high and the records obtained were taken in the period of magnetic storm or strong magnific disturbance. The error of results were analysed and discussed. It could be found that there were systematic changes in the apparent resistivity in some frequency range associated with the occurrences of earthquakes of M≈5 around the site. It is possible to get the stable impedance tenser apparent resistivity curves and other geophysical function of responses by MT observation with high accuracy, so that MT could be one of the means, which is used to monitor the temperary change of resistivity in the depth corresponding to the focus. Further observation and test of the temperory change of apperent risistivity by MT associated wity earthquake preparatory process is needed.
1987, 9(1):62-68.
Abstract:In this paper are analysed Characteristics of the distribution development, recent activity of east-northern structures and their mechanical feature in Gansu Qinhai and Ninxia areas and emphasized independent position of the genesis and kinematics of these structures and their control of earthquakes.
1987, 9(1):69-73.
Abstract:This paper introduces how the sample of sandstone makes various changes of its strength, deformation and the travel time of P wave vertical to stress direction, under dry and saturation conditions and along with horizontal stratification and vertical stratification when the single axis oading is conducted.
The results show that water makes an influence on the strength and the velocity of P wave of sandstone, and the sandstone sample of primary stratification has a definite direction of its strength, deformation and the velocity of P wave. The result is of the importance of reference to reservior earthquakes, seismic engineering and mines.
1987, 9(1):74-82.
Abstract:This Paper introduces the earthquake and the geological situation in Arsnan region, on the base of which are discussed the formation of the structure and its development and the characteristics of the seismic deformation zone. It is considered that Shelifu Basin has been developed and shaped since Iate Cenozoic Era, NE Arsnan fault has been in a strong activities since Quarternary and this earthquake is the result of the continuous activities of this fault.
1987, 9(1):86-102.
Abstract:With the expansion of human engineering activity both in scale and in sphere, there appears an accompaning new problem——induced seismicity in these decades especially in the last two decades. Many activities would intensify seismicity, such as impoundmen water in reservoir, large scale opencut mining and underground mining 9 waste liquid disposal,geothermal power generation as well as filling of high pressure water into the ground for a second time of petrolium exploitation, large scale drawing of underground water in cities and the post effect of underground nuclear detonation, ets. Since induced seismicity are accompanying engineering projects and occur near the large engineering projects triggering them, obvious social and ecnomic consequences would be incurred.therefore even as weak as M=5 magnitude, an earthquake has to be taken into account. Among various kinds of induced seismicity already known, reservoir induced seismicity (usually called reservoir earthquake) is most worth heeding. The Xinfengjiang Reservoir in China, the Kremasta Reservoir in Greese, the Kariba Reservoir in the border area between Zambia and Zinbabwe and the Koyna in India, all had triggered strong earthquakes of more than 6 magnitude one after another in 1960s, and such earthquake is most serious in Xinfengjiang and Koyna.
1987, 9(1):103-107.
Abstract:现在使用的R(△)是在原始震级基础上,由李善邦、郭履灿分别用我国的资料进行过两次修正后得到的。但是,由于地区的差异,R(△)还不能完全适合各个地区。本文的主要工作是参照文献[1]与[2]的方法,用统计方法对现使用的R2(△)进行修正,以得到尽可能代表新疆地区区域特征的量规函数R3(△)。此外,为了减小地壳横向非均匀性的影响,还求得了各台校正值。
1987, 9(1):108-112.
Abstract:近年来,国内外不少学者都在致力于现代构造应力场的研究,试图根据现代构造活动特征来探讨地震孕育和发生的规律。本文根据光弹模拟实验研究了我国中部地区现今构造应力场的特征,根据实验中的最大剪应力集中区,对本区未来强震的活动趋势作了初步的估计。
1987, 9(1):113-114.
Abstract:目前的地震分析工作依赖于人工查找走时表,因此计算速度慢、效率低,尤其是测定震源深度的准确率低,进而影响到震中的测定精度。为了提高工作效率,快速而又准确地分析计算出地震的各种参数,笔者编制了利用PC-1500袖珍计算机来分析处理近震的程序。
1987, 9(1):115-116.
Abstract:盛家峡水库位于青海湟水河南岸一级支流岗子沟的盛家峡谷(北纬36°22.5',东经102°21'),库容量450万立方米,坝高35米,建于1980年11月。近几年最高蓄水量为120万立方米,每年10~11月蓄水,第二年3-4月排空,属于年调节型水库。
Sopyright:China Earthquake Engineering Journal