SEISMOLOGY AND GEOLOGY

STUDY ON SEISMOGENIC PROBABILITIES OF POTENTIAL HYPOCENTER REGIONS IN THE CENTRAL QINGHAI-TIBET PLATEAU USING A TECTONOPHYSICAL METHOD

Wang Shengzu

1993, 15(1): 1-20.

Asbtract ( )

PDF (2517KB) ( )

Related Articles | Metrics

A deterministic-cum-probabilistic tectonophysical method is used to estimate the hypocentral parameters and seismogenic probabilities of the potential hypocenter regions before and after the Nov. 5. 1988 earthquake (M_s=7) west of Tuotuoheyan in terms of the tectonic feature, stratigraphic structure, geoth-ermal environment, and driving background in the central Qinghai-Tibet plateau. As a result, the earth-quake risk tendency of this area is discussed.

BOUNDARY ELEMENT MODELLING OF FORMATION MECHANISM OF SOME CHARACTERISTIC GEOMORPHOLOGY OF THE XIANSHUIHE FAULT ZONE

Zhang Chao, Chen Lianwang, Zhao Guoguang

1993, 15(1): 21-27.

Asbtract ( )

PDF (866KB) ( )

Related Articles | Metrics

Ground surface deformations due to some kinds of active structures have been modeled by the boundary element method. In terms of the theoretical results and the related geological data for the Xianshuihe fault zone, the formation mechanisms of the Dandu upheaval along the northwestern segment of the fault zone and the Huiyuansi pullapart basin in the middle have been discussed. It is concluded that the Dandu upheaval is caused by the local horizontal stress concentration due to the barrier of the fault bend to the left lateral strike slip on it; and the Huiyuansi basin reflects the effect of horizontal extension in the crust which is created by the non-equal left lateral strike slips on the two left stepping faults. Such structures may show the segmentation of the Xianshuihe fault zone and could control to some extent the start and end of some seismic ruptures.

ACTIVITY OF THE JINSHA AND LANCANG SUTURES, NORTHERN QINGHAI-XIZANG PLATEAU IN LATE QUATERNARY

Wu Zhangming, Wang Yipeng, Ren Jinwei, Ye Jianqing

1993, 15(1): 28-31.

Asbtract ( )

PDF (10593KB) ( )

Related Articles | Metrics

LATE PALEOZOIC PALEOMAGNETISM AND TECTONIC IMPLICATION FOR NORTHEAST JUNGGAR BLOCK, XINJIANG UYGUR AUTONOMOUS REGION, CHINA

Cheng Guoliang, Li Yongan, Li Suling, Li Qiang, Zhang Hui

1993, 15(1): 32-44.

Asbtract ( )

PDF (1748KB) ( )

Related Articles | Metrics

The virtual geomagnetic poles (V. G. P) in Late Paleozoic for the Junggar block are not distinct obviously from those of the Tarim and the Kazakhstan blocks but the observed paleolatitudes close to the expected values calculated from paleopoles of Kazakhstan block. Therefore the Junggar and the Kazakhstan blocks were a coherent geotec-tonic unit in the Late Paleozoic. The paleomagenetic data show that the Junggar ocean in the Devonian was closed in late Carboniferous at Urlunqur River area. The tectonic evolution of Tarim and Kazakhstan blocks underwent an almost the same course as that of Siberian platform which is representative of eastern Laurasia. Siberian platform has moved northwestward from lower to higher latitudes from Late Paleozoic to early Meso-zoic and migrated southeastward since Jurassic.

THE CRUSTAL MAGNETIC STRUCTURE IN THE EASTERN QINGLING MOUNTAINS

Zhan Chuanfu, Wang Zhehui

1993, 15(1): 45-50.

Asbtract ( )

PDF (1008KB) ( )

Related Articles | Metrics

Inversion of the aeromagnetic data has been made for the crustal magnetic structure and the deep fault structurs along with the magmatic intrusion and geological data; the crustal dynamic process and tectonic evolution in the eastern Qinling Mountains have been discussed as well.

APPLICATION OF PATTERN RECOGNITION TO DETERMINATION OF POTENTIAL SEISMIC SOURCES IN LIAONING PROVINCE AND ITS ADJACENT AREA

Jiang Xiuqin, Wang Guoxin, Li Dongchun

1993, 15(1): 51-56.

Asbtract ( )

PDF (859KB) ( )

Related Articles | Metrics

On the basis of seismogeology, geophysics and seismicity, the improved Cora-3 and Hamming method are used to delineate the potential seismic sources with magnitude of 6,6.5 and more than 7 in Liaoning Province and its adjacent area, the results deduced from two methods are consistent each other. Through the tests of k value, deleting objects and characters it is enough to prove the achieved result reliable and convincing. This work may bridge the gap in regrad to the field of the pattern recognition which has been carried out in Liaoning region and provide a basis for determing the potential seismic sources in Liaoning Province and its adjacent area.

THE SOUTHERN YELLOW SEA Ms 5.3 EARTHQUAKE OF JAN.23,1992

Li Jialing, Chao Hongtai

1993, 15(1): 57-60.

Asbtract ( )

PDF (499KB) ( )

Related Articles | Metrics

In the northern area of southern Yellow Sea, an Ms 5.3 earthquake occurred on Jan. 23, 1992, which is just in the forecasted risk area of 1992. The earthquake sequence is distributed dominantly in NE-direction and secondarily in NW-direction, and the long axis of the isoseismic lines is slightly in NE-direction, accordant to the characteristics of structure near the epicentral region in which the NE-direction faults are dominant while the NW-derection ones are secondary. So we think that this earthquake might be generated by the two groups of the conjugate faulting trending NE and NW, respectively but mainly along the NE-direction one. Moreover, based on the intensity of the historical seismicity and the scale of the faults, we infer that the moderate-strong earthquakes will be dominant in this area with little potential for generating Ms≥7 earthquakes in future.

PETROLOGY EVIDENCE FOR SEISMIC EVENT IN GEOLOGIC HISTORY-WITH AN EXAMPLE OF SEISMITE IN THE SEDIMENT OF LATE JURASSIC LAKES IN THE EMEI MOUNTAINS, SICHUAN PROVINCE

Yin Guoxun, Tang Youyi

1993, 15(1): 61-65.

Asbtract ( )

PDF (764KB) ( )

Related Articles | Metrics

Seismite is a petrological record of seism event in geologic history. From the bottom to top, the seismite sequence is composed of microfault bed, rubble bed and homogeneous bed. As a peleo-seisometer. The seismite can be used to understand seismicity and migrating laws of seism in geologic history.As a living example of seismite the authors discovered in Emei Mountain, authors have described various characteristics and summarized the marks of seismites.

RELATIONSHIP BETWEEN MAXIMUM FOCAL DEPTH OF EARTHQUAKE AND SURFACE HEAT FLOW IN FUJIAN AND TAIWAN REGIONS

Hu Shengbiao, Wang Jiyang

1993, 15(1): 66-68.

Asbtract ( )

PDF (500KB) ( )

Related Articles | Metrics

HYDROGEN——A SENSITIVE ELEMENT TO PREDICTABLE EARTHQUAKE

Zhang Peiren, Wang Jihua, Sun Fengmin

1993, 15(1): 69-77.

Asbtract ( )

PDF (1252KB) ( )

Related Articles | Metrics

Following M7.8 Tangshan earthquake of 1976,6 moderate-strong earthquakes with magnitude of greater than 5 and a sequence of moderate-small earthquakes with magnitude of greater than 3.5 had occurred successively in the capital circle untill 1991, such as M6.9 Ninghe earthquake of 1976 and M6.1 Datong earthquake of 1989 and so forth. A distinct increase of anomalous cocentration of hydrogen in thermal underground water might be observed by the hydrochemical monitoring network lying in the Beijing area preceding or following moderate-strong earthquakes and parts of moderate-small earthquakes, with its amplitude up to a few times or more than ten times, even to tens,of times the normal background value, which returned to the normal following the earthquake, suggesting that groundwater hydrogen forms a part of geochemical compositions sensitive to the stress-strain of the layers and also that it is a hopeful tool for the prediction of earthquakes.

CONFERENCE OF ASSOCIATION FOR STUDY OF GEOLOGICAL SCIENCE AND TECHNOLOGY PERIODICAL PUBLICATIONS AND ITS SEMINAR HELD IN WUHAN

Xiao Shan

1993, 15(1): 77-77.

Asbtract ( )

PDF (1252KB) ( )

Related Articles | Metrics

STUDY OF GEOTHERMAL RESOURCE IN ZHEJIANG PROVINCE

Ouyang Ting, Zou Yong

1993, 15(1): 78-81.

Asbtract ( )

PDF (496KB) ( )

Related Articles | Metrics

REGRESSION ANALYSIS OF MORTALITY AND THE RATIO OF COLLAPSING HOUSES BY TANGSHAN EARTHQUAKE

Cheng Jiayu, Yang Zhe

1993, 15(1): 82-87.

Asbtract ( )

PDF (780KB) ( )

Related Articles | Metrics

The ratio of collapsing houses by Tangshan earthquake was determined by sampling from aero photographies which were taken after shock. Analysis of mortality shows that the death percentage related to collapse of houses is more than 80%. Based on the fact that the death is mainly caused by collapse of houses, the regression curve of mortality and the ratio of collapsed houses by Tangshan earthquake is formulated. This curve can be used to rapidly estimate the death after shock by using the phase of damaged houses which can be surveyed from aero photographes.

STUDY OF ISOTOPIC RATIOS OF SOME INERT GAS FOR THE WUDALIANCHI VOLCANIC REGION

Kong Lingchang, Zhao Yi

1993, 15(1): 88-89.

Asbtract ( )

PDF (280KB) ( )

Related Articles | Metrics

CALIBRATION OF STRESS AND CONFINING PRESSURE IN EXPERIMENT OF ROCK DEFORMATION UNDER HIGH PRESSURE AND TEMPERATURE BY USING NaCI PRESSURE TRANSMITTING MEDIUM

Yue Shi, Ma Ri

1993, 15(1): 90-96.

Asbtract ( )

PDF (858KB) ( )

Related Articles | Metrics

There is a great difference between the real confining pressure and axial stress in the specimens in the high pressure-temperature experiment, because of the existence of frictions between the pressure medium assembly and the wall of the vessel and the specimen assembly, and of the behavior of pressure transmitting solid medium in use. The two factors causing the error were determined by experiments.This paper is to introduce a new mothod of pressure calibration and the calibration results. The performance of NaCl to transmit pressure is obviously improved with temperature increasing, but without apparent variation with increasing confining pressure. The values of the frictions decrease with elevated temperature and increase with increasing confining pressure. Generally, the quantity of modified confining pressure and axial load determined is considerably high, even up to several hundred MPa, much of which may be taken by the high friction in the vessel.

Table of Content