Table of Content

01 September 1993, Volume 15 Issue 3

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Brief Report

A DISCUSSION ON THE RELATION OF CIRCULATION DEPTH OF HOT SPRING WATER TO SEISMIC ACTIVITY ON THE NORTHERN SEGMENT OF THE HONGHE FAULT ZONE

Lin Yuanwu

1993, 15(3):  193-206. 

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Heat reservoir temperature of water samples collected from 14 hot springs on the northern segment of the Honghe fault zone is calculated by using SiO₂-geothermometer, and in connection with local geothermal gradients, circulation depth of the hot spring waters is also calculated. Meanwhile, frequency and focal depth of earthquakes occurring from 886 to 1987 are counted up and analysed. From the point of view of weakening effect of water on fault and its wall rocks, the author discusses the effect of deep circulation of the hot spring water on strength and frictional force of fault and seismic activity. The result indicates that difference in the seismic activity on each sub-segment is related to the degree of weakening effect of water on the various sub-segments. It is suggested that the Eryuan sub-segment on which the circulation depth of the hot spring waters is greatest corresponds to a slip zone, while the Jianchuan and Midu sub-segments on which the circulation depth of the hot spring waters is smaller, and Dali sub-segment with very few hot spring correspond to the locked zones, and that a strong earthquake would be prepared at both ends of the zone in which circulation depth of hot spring waters is greater.

NEW PUBLICATION——COLLECTED PAPERS ON OIL AND GAS GEOLOGY OF YINGGE SEA BASIN

Xiao Shan

1993, 15(3):  206-206. 

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A SIMPLE AND CONVENIENT TEST FOR DETERMINING TRANSMISSIBILITY OF AQUIFER IN WELL

Zhang Zhaodong, Wang Xueju, Feng Zhaicheng

1993, 15(3):  207-212. 

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In this paper a new test method for determining transmissibility of an aquifer in well is described. Using a test of step change of air pressure at well head, the transmissibility of an aquifer in Liaocheng city is determined to be 14.4m²/d. But it was determined by pumping test to be 43.6m²/d. Both the data have the same order of magnitude. This test is more simple and convenient, more economical and faster than the pumping test. It is also more reasonable to explain the micro-regime of groundwater and easier to be used in practice.

ON NONLINEAR CHARACTERISTICS OF EARTHQUAKE PRECURSOR TIME WITH REFERENCE TO HAICHENG AND TANGSHAN EARTHQUAKES

Deng Zhihui, Ma Jin

1993, 15(3):  213-219. 

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Earthquake focus system is a dissipative system which continuously exchanges energy and mass with outside. There will be a series of bifurcations in the process of earthquake preparation. The precursors of 1975 Haicheng earthquake in Northeast China and 1976 Tangshan earthquake in North China are studied with nonlinear dynamic method. There are 5 similar precursor stages for the two earthquakes. The durations reduced sequentially from the first stage to the fifth stage. The ratio of the durations of the two adjacent precursor stages is a constant (about 5). Five stages bagan about 2.5 years, 5.5 months, 1 month, 6 days and 1 day separately before the earthquake occurred.The main precusor features are: (1) gravity anomaly, (2) strain and stress conversion or jump at the background of strain and stress anomaly, (3) anomaly of the groundwater in very large region, (4) great variation of the air temperature and the geotemperature, the fluctuation of air pressure and the abnormal behaviors of domestic animals, and (5) eaarthquake lighting, earthquake sounds frequently and seriously disturbed radiowave.This relationship of precursor stages resulted from the period-doubling bifurcations in earthquake focus body with the increase of earthquake preparation time. Each grade bifurcation point corresponds to one precursor stage start time. The ratio of the durations of two adjacent precursor stages approximates to well-known Feigenbaum number (4.67). According to this relationship, we can predict the start time of later precursor stages and main shock time when two or more precursor stages are known.

GEOLOGICAL TRIP ON TIANCHI VOLCANOES IN CHANGBAI MOUNTAINS AREA

1993, 15(3):  220-221. 

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THE DIFFERENCE OF THE BREAKING CHARACTERISTICS BETWEEN THE DATONG EARTHQUAKE SEQUENCE AND THE LANCANG EARTHQUAKE SEQUENCE

Diao Gulling, Yu Limin, Li Qinzu, Wang Shaojin

1993, 15(3):  222-228. 

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The breaking process and combinated relation of earthquake swarm in the Lancang earthquake sequence of November, 1988, and the Datong earthquake sequence of October, 1989, have been analysed and discussed by means of analysis of the data about focal mechanisms of stronger earthquakes, a lot of focal mechanisms of moderate and small events, the epicenter distribution, isoseismals, seismogenic structures and so on. It shows that there are defferences between Lancang and Datong sequences. The Lancang sequence is caused mainly by renewal activity of the three preexisting faults, and the Datong sequence-by newly generated volume fracture.

THE PELATIONSHIP BETWEEN TEMPORAL VARIATIONS OF PRESENT STRESS IN A PART OF FAULT PLANES AND SEISMICITY IN NORTH CHINA

Liang Haiqing, Liu Jianzhong, Liu Qixiang

1993, 15(3):  229-238. 

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49 sets of in-situ stress measured during 1966～1984 in North China have been used to calculate the effective stress ratio on active fault plane near measuring site. A certain relation was found between the variation of the ratio of effective normal stress to shear stress with time and seismicity. Because of the difference of seismicity at various sections, the corresponding effective stresses are different, even if along the same fault in the same time period. It can be thought from the analysed data that for the effective stress less than 0.5, the seismicity along the fault is weak and the fault is stable, and on the contrary, it is not stable.

APPLICATION OF RENEWAL PROCESS AND PROBABILITY ASSIGNMENT MODEL TO CALCULATING EARTHQUAKE OCCURRENCE PROBABILITY FOR POTENTIAL SEISMIC SOURCE AREAS

Dong Ruishu, Gu Degui, Ran Honglui

1993, 15(3):  239-246. 

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Considering the influence of the last earthquake, in this paper we study two occurrence rates of earthquakes with various magnitudes in the northern part of North China and test them by renewal process and double Poisson model; then we obtain earthquake occurrence probability for each potential seismic source area in future 50 years by using probability assignment model.

FORMATION MECHANISM OF MICROEARTHQUAKE SWARM IN YANGUAN AREA ON THE YANGTZE GORGES

Yang Qingyuan, Chen Xiancheng, Ma Wentao, Hu Yuliang, Hu Ping, Zhao Meng

1993, 15(3):  247-252. 

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The activity of microearthquake swarm is limited in an area of coal mine. There are two types of microearthquakes: one is the microearthquakes the first motion of which distributed in a quadrant belongs to double-couple sliding focal mechanism, with S wave energy higher than P wave energy. The other is the extreme-low microearthquakes, with P wave energy higher than S wave energy. The focal mechanisms are the nondouble-couple. Both they are coal-mine tremors, which can not be considered as an evidence for the northern extension of the Xiannushan fault.

THE TECTONIC PATTERN AND SEISMIC CHARACTERISTICS OF MABIAN-YONGSHAN SEISMIC ZONE

Han Derun

1993, 15(3):  253-260. 

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Many investigations have been made on a series of strong earthquakes that occurred in Mabian-Yongshan-Leipo, Daguan area successively. Basing on the characteristics of folds and faults and distribution of stress, we suggest that there exists a relative variation process, being from strong to weak, from west to east. It is inferred that the source of stress may be derived from a lateral pushing force and the resulting seismic zone forms a part of Mabian-Zhaotong-Qujing fault zone, being an eastern boundary of longitudinal tectonic zone in West Sichuan, and also being an earthquake-controlling basement fault zone along the boundary between geotectonic elements, Qinghai-Xizang plateau and Sichaun basin.

A DISCUSSION ON EARTHQUAKES IN HUAXIAN, SHANXI PROVINCE, AND IN YUEYANG, HUNAN PROVINCE, IN 1556

Pan Jianxiong, Wu Yebiao, Zhang Yuxin, Xue Jiamou

1993, 15(3):  261-267. 

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In 1556, seismic shocks occurred in Huaxian, Shanxi Province, and in Yueyang, Hunan Province. Whether the seismic shocks belong to one earthquake? For this purpose, we studied the attenuation of seismic intensity, the similarity of the isoseismal forms of several strong earthquakes in and near Huaxian area, and the W-E-trending Qinling tectonic belt acting as a barrier for the seismic wave propagation. The results show that the boundary of seismic intensity IV of the great Huaxian earthquake lies in Xiangyang-Guangshan zone, near the 23℃ N. That is to say, there is an aseismic belt between Huaxian and Yueyang, and south of the aseismic belt there is another high-seismic intensity area up to VII. For that the epicenter must be near Yueyang, From where the seismic intensity attenuated outward and a closed boundary of intensity contour was formed. It indicates that the earthquake occurring in Yueyang is simultaneous but independent from the Huaxian earthquake in 1556. After then the high seismic frequency in Yueyang area lasted about 20 years. It means a period during which the regional stress was adjusted after the earthquake, whereas the anticlockwise rotational deformation in the upper part of Cisi Pagoda in Yueyang might result from the strong earthquake.

AN ELEMENTARY INTRODUCTION TO NATURAL DRINKING MINERAL WATER

Jiang Fengliang, Zhu Kewen

1993, 15(3):  268-268. 

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SEDIMENTARY FACIES OF THE HOLOCENE BEACHROCKS ALONG ZHEJIANG COAST AND ITS SIGNIFICANCE

Ma Kejian, Feng Yingjun

1993, 15(3):  269-276. 

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The characteristics of sedimentary environment, petrology, organic remains in the beachrocks, and genesis of formation of the beachrocks along the Zhejiang coast are described in detail in the paper. The study is of important scientific significance.

REINTERPRETATION OF P_g WAVE REFRACTION DATA ALONG PROFILE HQ-13 IN JIANGSU BY GRM METHOD

Zhang Huifang, Xie Jianbo

1993, 15(3):  277-284. 

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In this paper, a new method, general reciprocal method(GRM), is used in interpretation of P_g wave data along HQ-13 line in Jiangsu Province. By the GRM method, wave data are firstly processed on microcomputer and then interpreted. The procedure is more fast and more effective than traditional method. The result of processing of drill data comfirms that the GRM solution is more accurate than that of T_oT_p method.

A BRIEF ON INTRODUCTION TO ENGINEERING SEISMOLOGY

Jiang Li

1993, (3):  284-284. 

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Brief Report

HOLOCENE EARTHQUAKE DEFORMATION ZONES AND THEIR DISPLACEMENT AND SLIP RATE ALONG THE XIDATAN-DONGDATAN OF KUSAIHU-MAQU FAULT IN NORTHERN QINGHAI-XIZANG PLATEAU

Ren Jinwei, Wang Yipeng, Wu Zhangming, Ye Jianqing

1993, 15(3):  285-288. 

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