Hou Weirong , Wang Tingxuan , Zhao Yiquan , Liu Fengxiang
1996, 18(2):1-4.
Abstract:The earthquake waveform analyses and processing are not general processes of numerical analyses or data editing. In the processes,many links need to concatenate man's imagerecognize experiences and computer to judge correctly. Up to now,it is impossible for computer to automatically and accurately analyse and process the earthquake information without man's help. To analyse or process earthquake waveforms by man-machine concatenation in the telemetric seismic network is the first step in China. In order to develop the processing method,the authors successfully manufacture the earthquake waveform analyzing and processing system by man-machine concatenation in the Lanzhou telemetric seismic network.The system processes earthquakes through earthquake waveform displayed by computer.This system is suited not only to rountine earthquake waveform analysing,but also to time,location.and magnitude analyses of an earthquake event. In this paper,design, module structure,function and feature of this system are introduced.
Bi Qiuju , Liu Weihe , Fan Shihong , Qi Yufang , Zheng Tianxin
1996, 18(2):5-11.
Abstract:In this paper,the method of rapidly distinguishing the seismic trend is studied based on the spatial distribution characteristics of seismic sequence and by using the common ways in seismology. The preliminary test was made to rapidly judge the trend using the data from a single station and some useful results were obtained.
1996, 18(2):12-17.
Abstract:The Characters of reservoir earthquakes and mining earthquakes in Hubei, Hunan, Guangdong,etc.are analyzed comprehensively and a special earthquake belt, or an induced earthquake belt is established preliminarily based on the data of regional seismogeology, deep-seated structure,etc. It is considered that the special earthquake belt in Hubei-Hunan-Guangdong region has relation to active Zigui-Changde-Heyuan deep-fracture zone.
Wang Zhouyuan , Fan Shihong , Ji Fengying , Zhang Shuxun
1996, 18(2):18-25.
Abstract:Using P and S wave arrivals of local and near earthquakes,the crustal structures' of 7 subregions in Gansu were.inverted. The results show that:(1)vertical heterogeneity of velocity for Hexi region is greater than that for Hedong region, and those of focal regions of Haiyuan and Gulang MS events are greater than those for other regions,but horizontal heterogeneity is contrary. Vertical and horizontal inhomogeneity of upper crust(bounded at about 19 km depth) is greater than that of middle and lower crust;(2) velocity along the northeast edge of the Qinghai-Xizang block decreases along SSW-NNE direction in a regularly manner for upper and middle crust(bounded at about 30 km depth),but increases for lower crust; (3)horizontal inhomogeneity is characterized by outstanding lower velocity zone,which strikes along Qilian fracture system of SSE direction up to near Lanzhou, then extends southward to Zhouqu-Wudu,in middle section crosses lower velocity zone of the north edge fracture in western Qinling, but higher velocity areas locate mainly in north of Jiayuguanyumen, near Jingtai and south of Lanzhou etc.; (4) moderate and greater earthquakes occurred in not only lower velocity zones,but also higher velocity and other areas. The focal velocity of the two M8 events mentioned above is the lowest in middle crust of studied region. Thus,future strong earthquake possibly will occur near Lanzhou and in Zhangye-Minle region.
Xue Shunzhang , Zhang Shuxun , Liang Zibin , Wen Xinmin , Li Gang
1996, 18(2):26-30.
Abstract:Based on the model of horizontal layered media under ground and relevent electrical sounding data,the characteristic parameters such as disturbance coefficients (α,γ) and abnormal coefficient(β) which can represent the electrical structure of the media under station andhave ability of restraining disturbance and reflecting earthquake are calculated, and theirphysical characteristics and application in earthquake prediction are also studied in this paper.
The results of comprehensive research show that the parameters mentioned above are more objective than electrical sounding curves and electrical parameters and have advantages of quantitatively representing the electrical condition of station and having more extensive application.
Zhao Jialiu , Li Hailiang , Li Jian , Wang Yanqiong
1996, 18(2):31-36.
Abstract:In the paper, influences of the same interference on measurement results of apparent resistivity are quantitatively studied by using different observational methods. It is shown that observation accuracy of apparent resistivity could be improved greatly through up-down transmission. This observation method is applied to ZD8 geoelectric instrument and experimental results can be reproduced by the theoretical calculations basically.
Zhang Lingkong , Liu Beishun , Gao Fuwang
1996, 18(2):37-42.
Abstract:Based on the comprehensive comparison analysis of the Sacks body strain,atmospheric pressure,water level and pumping data at Changping station in Beijing, the disturbance of pumping to body strain is systematically expounded and the method for eliminating the disturbance is discussed. The results show that the body strain curve after eliminating the disturbance was corresponding to the Datong earthquake in 1989. This paper studies not only body strain but also groundwater level change and compares their similarities and differences.
Lin Changyou , Luo Dongshan , Wu Yuxia , Lu Fulin , Yang Changfu , Chen Junying
1996, 18(2):43-50.
Abstract:In this paper the source-effect characteristics of impedance apparent resistivity in magnetotelluric sounding (MTS), EM soundings with infinite line source(ILS)and electrical dipole source (FEM) which are EM soundings with different source equipments in frequency domain were discussed. On the basis of phenomenalized analysis a algorithm for reciprocated calculation of apparent resistivities in several EM methods——the source-effect correction algorithm was given(the 2-D apparent resistivity of TE mode in MTS and the 2-D impedance apparent resistivity of equatorial equipment in ILS and FEM). The model tests show that using this source-effect correction algorithm and through the 2-D apparent resistivity in MTS,the 2-D impedance apparent resistivity in ILS can be calculated in a better approximate degree. This algorithm is applicated to the calculation of the 2-D impedance apparent resistivity in FEM from the 2-D impedance apparent resistivity in ILS.
Li Qinglin , Li Wenshan , Zhang Xiaopu , Zhuang Jiancang
1996, 18(2):51-59.
Abstract:By using data for geothermal flow,geotemperature gradient and geothermal distribution,the distribution feature and difference are studied and the relationship of geothermal distribution with the shallow and deep structures of the crust is discussed in this paper. It is suggested that the values of geothermal flow and geotemperature gradient in Ordos block are lower,while a ring high anomaly belt appears in the vicinity of the block. The earthquake activities distribute mainly in the periphery of Ordos, that is to say,high heat flow, high geotemperature gradient and distribution of earthquakes in clusters are consistent in the vicinity of Ordos, indicating that a certain relationship exists between the geotherm and the earthquake activity.
Shi Xiaofei , Zhao Qiyuan , Lu Hanrang
1996, 18(2):60-66.
Abstract:According to the concrete situations of Wushan seismostation, a data management system has been successfully accomplished by using Fo-chase + 2. 10 in CCDOS environment. The system is mainly used to manage data and automatically generate all kinds of tables. The procedure is designed adopting top-down and stepwise refinement way. All of the modules have pull-down menu and man-machine interfaces are very friendly. In the procedure, maximum failure tolerance is adopted and its performance is very good. The practical run over a year has shown that the system perfectly satisfies the needs of day-to-day work of the Wushan seismostation.
1996, 18(2):67-73.
Abstract:The berth Xizang and south Yunnan the regions where earthquakes often occur. The seismic waves of the regions recorded by Gansu networks are obviously different from each other. The seismic wares in south Yunnan travel to lanzhou by way of the eastern margin of Qinghai -Xizang Plateau,their body wave trains mainly comprise short period compositions,and surface waves Lg1, and Lg2, are very remarkable and start sharply. The seismic waves in north Xizang travel to Lanzhou by way of the northeastern margin of Qinghai-Xizang Plateau, the short period part of seismic body waves is strongly absorbed by propagation medium, body wave and surface wave have some attenuation, Lg1, is not obvious or absent and Lg2, starts slowly and has a long period. The comparison results show that there are very different upper mantle and upper crust structures as well as different media and stratifications along the two propagation paths,so the absorptions to seismic waves are also different, resulting in differences of seismic records.
Lu Dehui , Xiang Guangzhong , Guo Wanwu , Chen Wenbin
1996, 18(2):69-95.
Abstract:The fault clay of some principal faults,including Altun,Changrna and Maornaoshan faults,along the northeastern border of Qinghai-Xizang Plateau is first studied. On the basis of the comprehensive analyses of the inner structures, country rock composition,fault clay thickness and quartz grain surface features within a fault zone,the fault activity ages and ways as well as the depth of fault gouges are discussed. The surface corrosion degrees of quartz grains can be classified into six types and each type has a corresponding age. The division standards of fault activity natures are proposed,by which the stick-slip and creep slip parts of a fault zone can be divided. Through the infrared spectroscopic analysis and rare earth element analysis, it is considered that the fault gouge formed at about 10 km depth within the crust.
Shao Shunmei , Zou Jinchang , Teng Ruizeng
1996, 18(2):74-79.
Abstract:The grain size distribution and microstructure characters of fault gouge in the east section of northern edge of western Mt. Qinling are studied for the first time based on the collected samples of natural fault gouge. The results show that the fracture zone takes stick-slip movement as the dominant factor and has creep-slip and extend-shear features at the same time.
1996, 18(2):80-83.
Abstract:遥测地震台网就是把不同空间分布的地震台网检测到的地震信号用遥测的方式实时或准实时地传送到台网中心进行集中记录和统一授时并用计算机处理地震数据的一种地震台网。遥测地震台网的速度快、精度高,使大地震参数的速报速度加快,并能及时建立地震目录库,可满足地震预报、科研、经济建设各方面对地震数据的要求。
1996, 18(2):84-89.
Abstract:近些年来,一些弱小地震在关中西部频频发生,它们主要集中在陇县-岐山-周至一带。据震源机制解分析,这些地震与陇县-岐山-周至断裂有关。该断裂是如何控制这些地震的发生与分布?断裂所在区域的地震危险区是陇县还是岐山?本文通过对陇县-岐山-周至断裂运动方式的研究,就以上问题进行了探讨。
1996, 18(2):90-95.
Abstract:周至地处陕西关中腹地。1988年1月和1993年4月,在周至分别发生ML4.3和ML3.6有感地震,这是近年来在关中地区发生的较引人注目的两次地震。震中烈度分别为V度和VI度,有感面积分别为1120 km2和630 km2(图1)。
Sopyright:China Earthquake Engineering Journal