Table of Content

06 March 1996, Volume 18 Issue 1

Previous Issue    Next Issue

Brief Report

THE TECHNIQUE OF TM DATA IMAGE PROCESSING IN THE INVESTIGATION OF ACTIVE FAULT ZONE ──XIANSHUIHE ACTIVE FAULT ZONE AS AN EXAMPLE

Zhang Jingfa, Wang Silong, Hou Xiaoqiang

1996, 18(1):  1-16. 

Asbtract ( )   PDF (8708KB) ( )  

Related Articles | Metrics

Fault movements tend to result in the variation of landscape and water system regime, which can be displayed directly or indirectly on TM images through color and spatial texture features. Data image processing techniques were used to extract and analyze the water system features,texture features and the water-bearing information of Xianshuihe region. Detailed study was made on the geometric morphological features and tectonic geological background of Xianshuihe active fault zone.

THE THEORETICAL RESEARCH ON THE RELATIONSHIP BETWEEN DURATION OF THE STRONG AFTERSHOCK ACTIVITIES AND RECURRENCE INTERVAL OF LARGE EARTHQUAKES

Zhang Guomin

1996, 18(1):  17-24. 

Asbtract ( )   PDF (1070KB) ( )  

Related Articles | Metrics

Some resarch results show that there is a relationship between duration of the strong aftershock activities and recurrence interval of large earthquakes, namly the longer the duration of the strong aftershock activities, the longer the recurrence interval of large earthquakes. In this paper, using rheology model, we derive the mathematical formulas of duration of the strong aftershock activities and recurrence interval of large earthquakes, and give the lognormal relationship between the recurrence interval of large earthquakes and the duration of the strong aftershock activities from theoretical research. Therefore the research in this paper provides theoretical basis for establishing the relationship between duration of the strong aftershock activities and recurrence interval of large earthquakes.

DISTRIBUTION OF PALEOTECTONIC RESIDUAL STRESS WITH DEPTH AND RESIDUAL ENERGY IN LONGMENSHAN FAULT ZONE

An Ou, Gao Guobao

1996, 18(1):  25-29. 

Asbtract ( )   PDF (723KB) ( )  

Related Articles | Metrics

Based on the anisotropic elastic theory of rock mass,the X-ray method is used to mesasure three-dimensional components of macro-residual principal stress,horizontal and verticl maximum shear stresses as well as its elastic strain energy density distributions with depth in rock mass on core samples taken from large aperture borehole series at three slies of the studied area on the Longmenshan fault zone. The regularities of their distribution with depth are analysed and the residual elastic strain energy stored in the rock mass of this fault zone are estimated.

GEOLOGICAL FEATURES AND FORMATION MECHANISM OF THE NAPPE AND BACKTHRUST ALONG THE YARLUNG ZANGPO RIVER(EAST SECTION)

Hao Jie, Zhou Xinhua, Li Qi, Chen Wenji

1996, 18(1):  30-36. 

Asbtract ( )   PDF (1192KB) ( )  

Related Articles | Metrics

There are two fault systems: Zangpo main nappe system(TMNS) and Zangpo backthrust system(ZBTS)along the Yarlung Zangpo River(east section).The TMNS consists of a series of the north-dipping thrust faults, such as the Renbung-Nedong subduction zone(RNSZ) and the Gangdese thrust-type ductile shear zone(GT).The former juxtaposes the Zangpo Ophiolite over the "Tethysan-Himalayan Zone" that is called as the N- Himalayan accretional complex in the paper, and it was formed from 100Ma to 40Ma.The Tethysan-Himalayan oceanic crust subducted under the Zangpo remnant oceanic crust which is composed of the basement and front ridge of the Xigaze-Sangri forearc basin; The latter juxtaposes the Gangdese batholith over the sedimentary sequence in the forearc basin or the Zangpo Ophiolite, and it was formed during the collision between the Indian plate and Asian plate from 40Ma to 26Ma. The ZBTS is consisted of a series of the south-dipping brittle thrust faults. Its main fault lies between the N-Himalayan accretional complex and the sedimentary sequence of the Xigaze-Sangri forearc basin or the Zangpo Ophiolite.The ZBTS is clearly younger than the TMNS, because its hanging wall strata overlie the TMNS. We have two guesses for the formation of the ZBTS. The first, during the late of the collision, the north part of the accretional complex locally thrust over the Zangpo ophiolite and the forearc sequence from S to N with the accretional complex shortening in NS direction;The second,the ZBTS composes the front zone of the N-Himalayan detachment fault system caused by gravity with rising of the Himalayan Mountains.

QUANTITATIVE RELATIONSHIP BETWEEN SURFACE RUPTURE PARAMETER, EARTHQUAKE MAGNITUDE AND RECURRENCE INTERVAL FOR SURFACERUPTURING-EARTHQUAKES IN WEST CHINA

Ye Wenhua, Xu Xiwei, Wang Liangmou

1996, 18(1):  37-44. 

Asbtract ( )   PDF (1088KB) ( )  

Related Articles | Metrics

Quantitative relationship between length(L)and maximun displacement(D)of strike-slip surface rupture zone, earthquake magnitude(M_s) and recurrence interval(T) for earthquakes in west China is empirically fitted. The result indicates that the earthquake magnitude M_s and recurrence interval T are closely associated with both rupture length L and maximum displacment D.M_s can be estimated from multiplication product LD, and T is closely related to the ratio D/L. Given M_s or LD for an earthuqake,the larger the D/L valus is,the longer the recurrence interval T becomes. Given surface rupture length L for an earthquake with longer recurrence interval T, its M_s or LD is larger. Given maximum displacement D for an earthquake with larger M_s or LD, its recurrence interval is shorter.

A PROBABILITY INCEASING MODEL APPLIED TO LONG-TERM EARTHQUAKE PREDICTION

Jin Xueshen, Dai Yinghua, Ma Guihua, Zhao Yunrong

1996, 18(1):  45-51. 

Asbtract ( )   PDF (744KB) ( )  

Related Articles | Metrics

A probability increasing model of strong earthquake occurence is discussed based on conditioned probability equation inferred for earthquake occurrence with precursors,At same time,the various calculation ways for unconditional probability are shown with non-uniform spatial seismicity and seismic data.Finally,as a example,the unconditional probability and the probability of strong earthquake in coming 10 years in seismic zones of North China have been calculated by several methods.

STATISTICAL ANALYSIS OF CRUSTAL VERTICAL MOVEMENT IN QUATERNARY PERIOD

Huang Xiuming

1996, 18(1):  52-58. 

Asbtract ( )   PDF (1018KB) ( )  

Related Articles | Metrics

We have done statistical analysis for descending amplitude of crustal movement in Quaiernary period (DACMQ).Those indicators,such as mean H,standard deviation σ,asymmetry A_s and kurtosis K_u on DACMQ,denote various character of seismic dynamics in subdistricts.The author considers that this method can be used as a powerful quantitative indicator for evaluating degree of seismic risk and researching dynamics of the earth.

RESEARCH ON EARTHQUAKE SOURCE PARAMETERS OF THE SOURTH AND NORTH SEGMENTS OF YITONG-SHULAN FAULT ZONE

Dong Ruishu, Liu Zhiping, Ran Hongliu

1996, 18(1):  59-65. 

Asbtract ( )   PDF (787KB) ( )  

Related Articles | Metrics

In this paper,the difference of earthquake source parameters and medium property has been studied,by using small earthquake maps within a time domain.The preliminary study result shows that the two segments in question show differential source stress drop and Q value,which can be explained by the earthquake activity.This method is a supplement of the study of fault within the depths of earthquake source,and provides an important means for fault segmentation.

PRELIMINARY INTERPRETATION OF MT DATA ALONG PROFILE FROM YANGGAO TO RONGCHENG:APPLICATION OF DECOMPOSITION OF MT IMPEDENCE TENSOR

Zhao Guoze, Tang Ji, Liu Tiesheng, Zhan Yan, Jiang Zhao

1996, 18(1):  66-74. 

Asbtract ( )   PDF (1279KB) ( )  

Related Articles | Metrics

Decomposion of the magnetotelluric impedance tensor is used in evaluation of MT data observed at sites along profile from Yanggao in Shanxi province to Rongcheng in Hebei province.The impedance tensor at some sites is influenced by strong local telluric distortion.Analysis on all data along the profile suggests that regional anomaly is two-dimensionality in general.The pseudosection of apparent resistivity and impendance phase for regional anomaly can be compared with tectonics.

STUDY OF THE ACTIVE FAULTS ON SHABANLIANG RIDGE IN DATONG BASIN AND ITS MECHANICAL SIMULATION

Dong Wenzhong, Hou Jianjun Liang, Haihua, Zheng Wentao

1996, 18(1):  75-82. 

Asbtract ( )   PDF (5059KB) ( )  

Related Articles | Metrics

Shabanliang ridge is a new uplift in the middle part of Datong basin and lies in an extensional environment.It is NE-trending and 60km long.Its bed rock is gneiss and is covered with Quaternary unconsolidated sedimentary layers,which include clay layers,fine-coarse sand layers gravel layers and loess layers.On the Shabanliang ridge there is a series of active normal faults in these unconsolidated layers.After field investigation,mechanical experiments in field and in laboratory to simulate behavior of active faults,the characeristics and types of the active structures on Shabanliang uplift are studied in this pater.The active sturctures,especially their extra ordinary pressentation forms in Quaternary unconsolidated sedimentary layers,are studied in detail,in order to find effective identification markers of active faults in Quaternary unconsolidated sedimentary layers.There are two kinds of active faults in general:visible and non-visible faults.The visible active faults can be divided into three types and the non-visible active faults can be recognized into four types.The difference between different types of faults is due to the difference in quality of sedimentary layers and forcing mode.By simulation experiments the influence of forcing mode (forcing slowly and rapidly) on sedimentary layers is analysed.These are very important to determine the most recent rupture time of active faults and how they are distributed in unconsolidated layers.By more precisely justifying the latest faulting,we can find the cycle of paleoseismic events more accurately and hence to evaluate the earthquake risk in engineering geology and to predict the possibility of earthquak.

EQUIDISTANCE ORDERING OF LARGE EARTHQUAKE (M≥7) IN NORTH CHINA

Xu Daoyi, Zheng Binghua, Zhang Cunde, G. Asteriadis, D. Arabelos

1996, 18(1):  83-90. 

Asbtract ( )   PDF (896KB) ( )  

Related Articles | Metrics

The spatial ordering of M≥7 earthquake epicenters in North China was studied quantitatively.The pattern of epicenters was identified in terms of simple geometric forms,such as isosceles triangles,equilateral triangles,and parallelograms.Statistics have been performed on the lengths of the sides of isosceles triangles which are considered equilateral.These side lengths are distributed in a range from 240-650 km.The equality of distances between large earthquakes permits us to reexamine the relationship between large earthquake and surface geological structure.It is suggested that the generation of large earthquakes may be more closely related with deep crustal structures,and surface faults are merely their expressions and response to their indirect effects.

FORMATION AND ITS SIGNIFICANCE OF HUANGHE RIVER CURVED REACH IN SHAPOTOU AREA,NINGXIA

Liu Chuanzheng

1996, 18(1):  91-96. 

Asbtract ( )   PDF (859KB) ( )  

Related Articles | Metrics

In the Shapotou,Ningxia,there is a abnomal curved reach,similar to "Ω" of Huanghe River just at the site where runs into the Zhongwei basin from the Heishan gorge.It is found that it is not a general snaking river but a river dislocation with two groups of listric faults of different directions and active behaviours across it.It is associated with the movement of both left-lateral strike-slip faults-nearly E～W striking Zhongwei-Tongxin fault system and right-lateral strkingslip faults-NNW striking Changle-Xingren fault system.