1995, 17(4):1-12,22.
Abstract:Based on data of author's field investigating, measuring and trenching, the distribution and rate of Holocene displacement, paleoearthquake's traces and times, recurrence intervals of strong earthquakes (Ms=8-8.5) and model of the earthquake fracture along the 1668 Tancheng earthquake fault are studied in the paper.
1995, 17(4):13-16.
Abstract:Coriolis force is a inertial force in earth rotation.It makes the fall body turn to east and the rising block turn to west.This is the reason why in the circum-Pacific seismic belt,the tectonic zones of western Pacific are different from those of eastern Pacific
Huang Qingtuan , Lei Tucheng , YeShengji
1995, 17(4):17-22.
Abstract:A M5.0 earthquake occurred in Liancheng on Nov.26,1992.The macroscopic epicenter is situated between Huangdi and Laiyuan(116°57'E,25°32'N),epicentral intensity is Ⅵ+,focal depth is about 7.5 km,The is oseismal map of meizoseismal region shows oblong,Its long-axis strike is NNE,which is same as the that of the Huangdi-Meicuntou fault in epicentral area. The aftershocks were distributed along the fault and migrated from NE to SW. Tt is considered that the Huangdi-Meicuntou fault might be seismogenic structure of this earth-quake.
Chen Youfa , Lei Jianshe , Ding Hui , Dong Qizhen , Ma Qinzhong , Kang Haolin
1995, 17(4):23-30.
Abstract:In this paper,the physical base of the mean square deflection method extracting information of multi-parameter earthquake precursors has been studied.The physical base of this method is that rock properties including elasticity,deformational property,electric property,magnetic property,thermal property and so on will change obviously when crushing stress reaches up to more than 50 percent during earthquake preparation,which results in changes of absolute value,variation rate and measuring error of rock physical parameters.To calculate the changes by using the mean square deflection method,on one hand,eliminates the seasonal interference of precursor parameters,on the other hand,gives prominence to the precursory informations.
Zhao Yiquan , Yao Tongfu , Liu Fengxiang , Lei Fang
1995, 17(4):31-35.
Abstract:An earthquake(Ms 7.0)occurred in Gonghe county,Qinghai Province,on Apr.26,1990.Is it a tectonic earthquake or a reservior earthquake? The telemetric seismic network around the Longyangxia reservior has recorded a wealth of earthquake data for the past 8years,only after the Gonghe earthquake,the network recorded 8,145 aftershocks,thus provides rich data for solution of the above-mentioned problem,There have been more and moreMs ≥ 5.0 earthquakes in the region since 1994.Therefore,the Longyangxia reservior region merits seismologists attention and studies.
1995, 17(4):36-41.
Abstract:By using quartz thermometer and the experiential formula qSiO2=(TSiO2-b)/m given by C.A. Swanberg and P. Morgan in 1980s,this paper studies the silica heat flow values alongNorth-South seismic belt,and analyses their trend and fractal property. In contrast to geologi-cal background,the paper also discusses the relationship between silica heat flow values and tectonic activities and prospects of application of silica-heat-flow method.
Yuan Daoyang , Liu Baichi , Lu Taiyi , He Wengui , Liu Xiaofeng
1995, 17(4):42-47.
Abstract:In this paper,on the basis of division and comparison of the Quaternary system and geo-morphic units in Baoku river area and according to the ages of specimens,authors analysed the characters of dislocated micro-geomorphology. The results show that Baoku River fault does not cut the first-order to third-order alluvial or pluvial terraces crossed by the fault.Through the thermoluminescent dating, authors found that the Baoku river fault has not revived since 66±8 ka. B,P. The Baoku river fault is a left-lateral and compressional reverse fault,and belongs to late Pleistocene fault.
1995, 17(4):48-55.
Abstract:In this paper,based on analysis and comparison of data about cultural remains and drainage changes in the north of Tibet plateau,the recent depression centers of basins are delimited and feature of neotectonic movement and its relation to seismic risk zone are studied, which will contribute to develop the intensity regionalism work.
Guo Shounian , Zou Mingwu , Gan Weijun , Y. Gaudemer , J. Ruegg , G. King , F. Metivier
1995, 17(4):56-60.
Abstract:In this paper,the establishment and the first observation of the Tianzhu GPS monitoring network which is situated in the north margin of the Qinghai-Xizang plateau and overlaps the Gulang-Haiyuan active fault zone are introduced.The initial processing results show that GPS may become one of the best methods to research recent crustal movement because of its high precision and efficiency.
Gao Yuan , Ji Ying , Chen Yong
1995, 17(4):61-69.
Abstract:Using the model made from lots of spring-blocks, we may model the complication of earthquakes,In this paper,by cellular automata(CA) as mathematical tools,with the results of seismology and rock mechanics,comsidering about the energy gathering and energy losses,we do digital modelling for earthquake events,then do multifractal analysis for "earthquakes" events from this model in both time and space fields,and discuss self-organized critical(SOC)state,Further,we get the conclusion in which event distribution shows hierarchy structure,at least, in time field and is coincident with self-similarity nature.This CA model is a determinacy Chaos system, its statistics for frequency and magnitude of lots of events under the state of SOC accords with Gutenberg-Richter index law well.The results show that although self-organized (SO)state might be more accurate earthquake expression,SOC still is a very good mode in earthquake studies.
Liu Baoqin , Zhu Zuoquan , Jia Zheng , Cuo Wanwu , Li Zhuguo , Zhang Wenren , Qu Jianpeng
1995, 17(4):70-78.
Abstract:The MT survey in Tianshui area shows that there is a high conductivity layer in the depth of 43 km,which may be the reflection of the crust-mantle transition zone. The lithospheric thickness is about 95-110 km. There might be a large crust-lithosphere tectonic zone nearly in EW direction around Taijing, Tianshui, and there might be also a large crust-lithosphere tectonic zone nearly in NS direction mear Yebu and Longcheng,Qin an,The two zones are all the boundary lines of different tectonic units.The Tianshui M8.0 earthquake in 1654 probably related to the thermal stress caused by the deep heat anomaly.
Deng Mingde , Geng Naiguang , Cui Chengyu , Zhi Yiqiao
1995, 17(4):79-86.
Abstract:The rupture experiments for rock samples of different properties and structures during uniaxial loading were made in laboratory.The following major results were obtained:(1)The radiation temperature of rock samples changed along with increasing of stress,the range of temperature change was 0.2℃-0.8℃。(2)The obvious temperature precursor appeared before rock rupture.(3)High-temperature belts and regions or low-temperature belts and regions appeared before rupture for some rock samples,then the major faults happened along the belts and regions.(4)The temperature pulses appeared before rupture for some rock samples, the plus pulses were about 2.8℃ and the minus pulses were about-1.0℃.(5)When the stress increases,the increasing of temperature and the increasing of AE rate of samples appear complementary relation.
1995, 17(4):87-88.
Abstract:在实验室内,用压机对样品加压时,压机和样品同时变形。当加压到一定压力时,样品发生破坏。由于样品的破坏,使得压机的形变得以恢复。
Lin Changyou , Wu Yuxia , Yang Changfu , Chen Junying
1995, 17(4):89-98.
Abstract:The characteristics of conductivity anisotropy of earth medium due to EDA phenomena were demonstrated,tha pattern and characteristics of MT response function variations caused by the changes of conductivity anisotropy were analysed and studied, the distinguishability of MTS to the earthquake precursor of EDA electrical changes and the necessity of considering the anisotropy in the interpretation of MT data were explained, and the.inverse problem of MT data for the symmetrically anisotropic layered medium was discussed.
Sopyright:China Earthquake Engineering Journal