Li Zailiang , Lu Zhenye , Yang Jialing
1988, 10(3):1-7.
Abstract:A lot of physical mechanism explaining earthquake lightning depends on the condition of high temperature rise when an earthquake crack propagating. This work has studied the temperature fields near a running crack tip from the theory of dynamic fracture mechanics. The numerical results have shown that when an earthquake is occurring, the temperature rise near the propagating crack tip may reach several hundred to near one thousand degree.
1988, 10(3):8-18.
Abstract:The equations of which the seismic waves are propagated in the viscoelastic medium have been built by imitating the viscosity properties of the earth with several ordinary viscoelastic bodies in this paper. The solutions of the problem have been obtained based on the proper approximate methods. It is given that the concept and the method which is used to estimate the viscocity Q value according to correct other factors causing the seismic waves energy decrease with Chebyshev polynomial approximate to power spectrum. At the end of this paper, the feasibility of the method has been is discussed.
1988, 10(3):19-24.
Abstract:In this paper, according to three kinds of seismic patterns as precursory of strong earthquakes, i. e. aftershock burst pattern b, earthquake swarm patterns and weight sum pattern ∑, put forward by Keilis-borok and Knopoff et al., taking Kangding-Luhuo seismic zone as a example, the existence and prediction effect of three kinds of seismic patterns are tested. The results show that, during 1967-1982, one, two and all of three kinds of seismic patterns can be produced in the seismic zone before 5 strong earthquakes (M≥6.0). The prediction effect of three kinds of patterns are rather satisfactory. Particularly, the prediction effect of the weight sum pattern ∑ is better. When the value of the pattern ∑ exceeds certain threshold value, there always were earthquakes (M≥0.6) to occur afterwards. Simultaneous appearance of two or three kinds of patterns can eliminate false forecast and improve the accuracy of earthquake prediction.
Lin Changyou , Wu Yuxia , Liu Xiaoling
1988, 10(3):25-38.
Abstract:In this paper some advance on the error research in magnetotelluric data process are reviewed. Using the measured MT data, we discuss characters of the error distribution of MT response functions and the characters of the error propagation in its estimation; further expound the practically applied effect of the multi-channel coherent function method, modified by author, on the unbiased estimation and the diminution of the errors of the estimated values; and also discuss some problems on the synthetical error evaluation using several MT parameters.
1988, 10(3):39-44.
Abstract:This paper makes a study for seven types of the SEM characteristics of the mineral arrangements of the gouges in Anninghe fault zone. The Combinations of the mineral arrangements are discovered, The movements of the stick slip and the steady-state slip of the fault zone are discussed by the combinations for the first time.
1988, 10(3):45-50.
Abstract:In 1986, the writer et al. suggested that a whole geosound sequence can be obviously divided into five periods, namely period of acoustic emission generating, period of acoustic emission accelerated, relativelly quiescent period of acoustic emission, period of main acoustic emission and period of acoustic emission decayed, based on the variation process of geosound wave form before and after earthquakes.
In this paper, the application and significance of the geosound sequence in the short-term and imminent prediction are further studied. In fact, the obtained results indicate that the observations of geosound on-site are compatible with the data of seismicity and experimental results in laboratory at all, so the geosound sequence might probably be used in the short-term and imminent pediction. Especially, the relative quiescent period in acoustic emission before earthquake can be taken as an impending earthquake signal.
Lu Yangquan , Qian Jiadong , Liu Jianyi
1988, 10(3):51-56.
Abstract:The results of experimental study on resistivity changers of the Xiaol-langdi sandstone samples with the bilateral shear method are presented in this paper.
The main feature of the results is that the trends of resistivity changes in different directions with respect to the loading direction are different during the loading process up to sliding. The resistivity increases steadily in the direction parallel to the loading direction but no change in the trend prior to the main sliding; the resistivity in the direction perpendicalar to the loading direction firstly decreases with big magnitude, then with small magnitude as loading stress increases and clearly shows the behavior of a sudden anomalous change right before the main sliding with the magnitude of 5.0%; the resistivity in the direction which is 45° with respect to the loading direction shows a trend of slow increases and after the trend reaches a maximum value it decreases. Furthermore, this paper also deals with possible causes of these results and their application in the study of earthquake prediction.
Ding Boyang , Lei Zhongsheng , Fang Shulan
1988, 10(3):57-65.
Abstract:Collecting intensity attenuation information of historical earthquakes and using Lny=a+bm-clnR-dR formula and ground motion attenuation in west part of U.S.A, authors got 20 experi mental attenuation relationships of different frequency by Hu Yuxian's method. Reforming in this paper:(1) Authors talk different from intensity on basement rock and loess region. The ground motion in basement rock is greater 0.6 time than in loess region. The coefficient 0.6 is from site response calculation of Xian and Baojl microzoning. (2) In unsymmetrial isoseismic on fault authors used longer side of short axis for safety. (3) Because of LnR and R is dependence, authors used 5 records of strong motion of Songpan earthquake in Aug.-Sept., 1976 for uncertainty assessment and didn't use formula of error of square.
Gao Delu , Guo Shifeng , Li Shugong , Chen Getian , Shao Jin
1988, 10(3):66-73.
Abstract:The authors present the principals, the measuring devices and method of a biaxial photoelastic strain gauge. It has been pointed out that the optimum position of measurement in the strain gauge depends upon the Poisson's ratio of the gauge material, only. Within a given positioning tolerance of ±0.25mm for the optimum measuring point, the maximum error of the measured differential principal stress is ±4%. Experiments show fringe patterns in the strain gauge with two clear and precisely perpendicular axes of symmetry, which indicate the directions of the principal strain. The biaxial photoelastic strain gauge made of proper materials with an outer diameter of 50mm, an inner diameter of 10mm, and a thickness of 4mm has a sensitivity of 6.45με. It provides a means of convenient, economic, and fast in-situ stress measurement.
Wei Siyu , Liu Shaocheng , Ao Guanghua , Teng Hongyuan
1988, 10(3):74-81.
Abstract:In this paper, the characteristics of geothermal activity and relations between these characteristics and magma activity, seismicity and deep structure in coastal areas of Fujian province are discussed, depending on the measurement of heat current, the shallow well temperature field and the study on the synthetic geophysical field in continental margin of Fujian province. The exploiting prospect of geotherm is discussed in this paper.
Liu Xiaohong , Hao Jinsheng , Fang Yaru , Cai Daien , Li Jihan , Geng Naiguang
1988, 10(3):82-84.
Abstract:为了研究断层的深部构造和深部断层物质的力学性质,在国外曾有人对一些大断裂带进行过地球物理勘探,得到横跨断裂带的速度剖面和密度剖面。在物探资料的反演过程中,由于构造和物性二者均是未知的因素,取得断层物质高压状态参量的实验数据是有意义的。人们在实验室中对断层泥的压密效应进行过实验研究。
Zhang Yuanfu , Zou Mingwu , Zheng Wenqing
1988, 10(3):85-88.
Abstract:1987年元月8日甘肃迭部发生了5.9级地震,地震前,我们根据该区域地壳垂直形变的中长期背景资料和固定台站的连续观测资料的异常变化,较准确地预报了这次地震。为了总结经验,提高预报水平,本文简略介绍了预报依据及震前的地形变特征,并进行了初步论证。
Zhao Guangkun , Jin Ming , Jiang Xuyuan
1988, 10(3):89-91.
Abstract:1979年郭增建、秦保燕首先提出前兆优显层[1],1982年又讨论了前兆优显层的深度,指出在深度5-8公里处是浅源大震前兆优显的层位,它可直接反映震源地方的动态过程,而且其前兆表现较其他层位要明显,并且各种干扰因素相对要少。
1988, 10(3):92-94.
Abstract:这次地震前近三年门源地区气压、温度均有上升趋势,降水起伏较明显。年平均气压和夏季(7-9月)月早均气压比多年平均值高1.0-2.6mb。1984年年平均气温比1983年高0.5℃,1985年比1984年高0.6℃,1985年年平均气温为0.7℃,比多年平均值高0.17℃,是近十年来最高的。
Dang Guangming , Tu Delong , Ye Jianqing , Zhang Ruibin , Jia Yunhong
1988, 10(3):95-97.
Abstract:1986年8月26日,青海省门源县境内发生了6.4级地震。地震发生后,青海省地震局与兰州地震研究所联合对震区进行了宏观考察。但由于自然条件所限,未能进入极震区。在这以后,青海省地震局、兰州地震研究所、青海省地质局联合组队,再次深入震区进行考察,确定了宏观震中及地震裂缝带,圈划了极震区等震线。本文主要以第二次考察所取得的资料为基础,论述和分析了这次地震极震区的地质震害类型和分布特征以及烈度分布特征。
Feng Deyi , Masaji Ichikawa , Hideteru Matsumoto , Chen Jinlin , Wu Guoyou
1988, 10(3):98-123.
Abstract:The present paper is a preliminary technical report of the development of ocean-bottom seismograph observation in the Bohai Sea area of China, conducted under financial support from Japan Foundation for Shipbuilding Advancement.
This report mainly includes the following contents:
(1) The seismicity and seismic risk assessment of the Bohai Sea area and its vicinity.
(2) Conditions for sea-bottom seismograph observation in the Bohai Sea area.
(3) Some results of preliminary study on instruments and techniques for ocean-bottom seismograph observation in the Bohai Sea area.
(4) The results of experimental modelling researches on the noises of ocean-bottom seismograph observation in the case of shallow sea.
The historical and present seismicity, the long-term seismic risk, and the relation between large earthquakes which occurred in North China and Japan have been studied. The problems on influences of a strong earthquake and tsunami upon the Bohai Sea navigation routes and near populated areas were discussed. Based on the result the necessity of sea-bottom seismograph observation in the Bohai Sea area was explained.
The conditions in the Bohai Sea area, introduced in this paper, include the sea-bottom geomorphology, strong waves and meteorological conditions, and the sea navigation and Sea work condition in this sea area.
Some problems on the instruments and techniques for sea-bottom seismograph observation in the Bohai Sea area were studied and discussed. The preliminary seismograph observation test at the platform of an oil well in the Bohai Sea area was made by the Seismological Bureau of Tianjin, Some new techniques, and successes in noise reduction and signal transmission etc. of sea-bottom seismograph observation advanced by the Meteorological Research Institute of Japan Meteorological Agency (JMA) may be applied to the sea-bottom seismograph observation in the Bohai Sea area. On the basis of these results, a preliminary project to develop the sea-bottom seismograph observation in the Bohai Sea area of China was proposed.
To study the noises of sea-bottom seismograph observation in the case of shallow sea, a new experimental modelling research has been completed. The noises caused by sea surface source and sea interior source were studied separately. Some important experimental results have been presented.
The preliminary results, obtained in this paper, may be useful to develop the sea-bottom seismograph observation in the Bohai Sea area and its vicinity.
1988, 10(3):124-127.
Abstract:Seismologists are interested in the linear structure and neted tectonic framework and their relations to seismicity from the remote sensing images, but do not pay enough attention to seismicity. The circular structure is a kind of particular tectonic pattern showing on the sensing images. By using the remote sensing, author has analysed seismo-tectonic environment in the northwestern region of China for several years. About the action of circular structure on study of earthquakes, some points of view are presented in the following.
1988, 10(3):130-130.
Abstract:节气是我国古人的创见,它属于东方科学观点,在农时上具有重大意义。除此之外,我们发现,它在灾害预测上也有价值。我们曾发现上海的龙卷风以及与我国同纬度的美国的龙卷风的发生在节气日占优势。今年以来我们对我国的灾害性天气作了检验,发现绝大多数也发生在节气日或其附近,其余多在期望日或其附近。
Sopyright:China Earthquake Engineering Journal