XU Jie , WANG Ruobai , WANG Chunhua , SONG Changqing
1998, 20(2):1-7.
Abstract:In previous seismotectonic studies,the emphasis was placed on the inherited active fault zones.In the recent tectonic stage that essentially keeps in step with the current regional geologic environment and the stress field,however,there are also some newly-generated fault zones.By studying the seismicity in North and Southwest China,it has been known that the NE-trending Tangshan-Hejian-Cixian and NW-trending Tengchong-Gengma-Lancang seismic zones are just two newly-generated fault zones.To distinguish them from the inherited fault zones,they are called the newly-generated seismotectonic zones.This paper deals with the existence of these two seismogenic zones from their seismicity and geological structures,gives a preliminary analysis on their characteristics and shows their significance.
ZHANG Yuansheng , LI Qinghe , XU Guoming
1998, 20(2):8-15.
Abstract:The damped least squares method in seismic wave travel-time inversion was expounded.In order to increase the uniqueness of solution, the interpretation results of deep seismic sounding data were constrained as a special condition.The genetic algorithm for seismic wave form inversion was discussed.
JIANG Jingxiang , LAI Aijing , HU Qun , XU Yangang
1998, 20(2):16-21.
Abstract:In this paper,several examples of predicting the Jiashi strong earthquake swarms in 1997 by using the drill-hole strain data are introduced and the primary characters of strain anomaly are analyzed. The results show that before the Jiashi swarms the trend change curves of drill-hole strain at Wushi station 250 km from the epicenter departed from their normal pattern and the short-imminent strain values changed suddenly.
HUANG Xuexiang , DING Jianhai , ZHANG Shulan
1998, 20(2):22-28.
Abstract:The relation between the anomaly of daily low-point displacement of geomagnetic vertical component and the MS≥5.0 earthquakes since 1985 in Xinjiang area is analyzed.The result shows that there are the characteristics both in seismicity and Geomagnetic low-point displacement anomaly in the area and they have a close ralation to the internal and external environments of earthquake preparation.
1998, 20(2):29-35.
Abstract:The basis to predict earthquakes by the double magnetic storm time method is that the crustal expansion and contraction caused by the migration of strain energy present a cycle with a double time relation.The Tangshan MS7.8 earthquake was the strongest one in 1970s in our country,it had a relation to four groups of magnetic storm energy based on the double magnetic storm time method.Every group of magnetic storm was headed or followed by earthquakes.When the residual energy accumulating after these earthquakes,the crust expanded and contracted,the geomagnetic field was affected and the magnetic storm formed.So the magnetic storm has a relation to variation of earthquake energy and earthquakes can be predicted by the double magnetic storm time method.
1998, 20(2):36-42.
Abstract:In this paper,the correlativity of seismic activity in Guangxi with those in the master seismic zones (belts) of China has been studied by using correlative analysis method of grey system theory.The results show that the degree of association of seismic activity is the largest between the Guangxi seismic zone and the southeast coastal seismic belt (r=0.86). Based on the results,the correlativity of seismic activity in the Guangxi seismic zone with that in the southeast coastal seismic belt has been discussed further.It is found out that the change of seismic activity has been synchronous in the Guangxi seismic zone and in the southeast coastal seismic belt since 1900,and that the correspondence relation of moderately strong earthquakes in the zone with those in the belt is very obvious.
CUI Duxin , JIANG Zaisen , WANG Shuangxu
1998, 20(2):43-51.
Abstract:In this paper,two new indices,quasi-acceleration of crustal vertical movement and crustal volume change rate,are presented,which will describe the characteristics of crustal vertical deformation field.The crustal shear deformation,extension deformation,quasi-acceleration and volume change rate are calculated by using releveling data in Hexi area,Gansu since 1970s. The relation between these indices and earthquake risk region judgment is analyzed systematically.The procedure of crustal deformation field evolution in Hexi area is studied.
XING Chengqi , ZHANG Jie , LU Dehui
1998, 20(2):52-57.
Abstract:Based on the comprehensive analysis of tectonic deformation,tectonically spatial distribution relation,fault plane occurrence change,tectonic stress field,etc.,it is considered that the Quaternary movement forms of the active fault zone along north margin of Mt.Altun underwent a gradual change process from compressional thrust through left-lateral strike-slip simultaneously with compressional thrust to pure left-lateral strike slip.Acting upon the change,evolution of regional tectonic stress field in the studied area is roughly divided into three stages during which the directions of compressive principal stress axes are near NS, NNE and NE in the order from the earlier to the later.The changes of tectonic stress field and fault movement form mainly are caused by the eastward slip of secondary block and eastward flow of lithospheric mass resulting from continuously northward push and pressure of the Indian plate.
1998, 20(2):58-61.
Abstract:In this paper,the theoretical formulas of the damage rate of seismic hazard and the total damage evaluation were deduced by using the formula of document[1],moreover,the rationality of earthquake resistance reinforcement was discussed,finally,the rationality of the theoretical evaluation was tested by calculating some actual cases.This study will conduce to deeply understanding the essence of hazard damage through the ralationship between hazard evaluation and theoretical intensity attenuation.
MA Erman , WANG Yanbin , ZHOU Junxi , LEI Zhongsheng , LIN Xuewen
1998, 20(2):62-69.
Abstract:A MS5.8 earthquake occurred in Yongdeng county of Gansu Province on July 22,1995. It caused buildings to get damaged,property to get lost and personnel to get wounded or to die. Immediately after this event,scientific investigation and earthquake disaster assessment groups are sent to the earthquake area.According to the principle and method in The Working Guidebook of Earthquake Disaster Investigation and Loss Assessment and based on the survey of general situation,natural environment,social economy,pillar estate,population and buildings,we investigated the samples of building destruction and loss of property in areas of intensity Ⅷ,Ⅶ,Ⅵ,Ⅴ.According to the earthquake disaster assessment software EDEP 93,the data base is set up.Results of scientific and reasonable earthquake disaster loss assessment are provided.The characteristics of earthquake area are analysed and the earthquake disaster distribution characteristics are also researched.Last,the experiences and lessons of protection against earthquake and disaster reduction are summed up.
QU Jianpeng , ZHU Zuoquan , YANG Guodong , LI Zhuguo , SHI Shuiyue
1998, 20(2):70-75.
Abstract:The magnetotelluric sounding results show that electrical structure is simple inside Ordos block and complex in the arcuate fault zones on the western border of the block.In the arcuate fault zones,lateral change of conductivity is severe and the low resistivity layer in upper mantle tends to deepen.This is different from Yinchuan fault basin where upper mantle structure is uplifted.It is considered that tectonics are tensional in the Yinchuan basin and compressional in the arcuate fault zones.In addition,deep electrical structure is uplifted between Daluoshan and Huianpu.It is shown that this is a deep-seated fault where the North-South tectonic belt passes through.
ZHANG Suping , WANG Lanwei , ZHENG Weiping
1998, 20(2):76-79.
Abstract:Two microcomputers which are within near distance (generally less than 50 meters) from each other are connected by using their standard serial interface RS-232C,according to a special link mode and without MODEM.When receiving,the way of hardware interruption is used to realize the real-time receiving of informationsand to share earthquake data.
1998, 20(2):80-87.
Abstract:A special coding-and-decoding transmitting system with multichannel remote control commands is introduced in this paper.Its key circuits are the keying decoding circuit,data selector circuit,ring time-delay demarcation circuit,coding circuit,oscillating frequency demultiplier circuit,control system circuit and carrier frequency amplifier circuit.The circuits have clever designs,strong practicability and wide application range.The long-term practice has proved that the system was very stable and reliable,and accorded with the demands of technical indices in the original designs.
1998, 20(2):88-89,92.
Abstract:A MS6.1 earthquake occurred in sea on the east of Changjing River mouth on Feb.9,1996.Tiltmeter at Huzhou station 290 km from the epifocus recorded medium- and short-term anomalies,and that at Ningbo station 240 km from the epifocus recorded short-term anomalies. This paper gives a description of anomaly evolutionary process and prediction of three factors.
1998, 20(2):90-92.
Abstract:甘肃省现有5个地应力观测站,分布在其东部和南部.近5年来,在全国资料评比中,这5个站的资料均被评为优秀,其中刘家峡站的资料质量较高,曾对其以西250 km范围内发生的几次6级以上地震有较好的反映[1],例如1986年门源6.4级地震前出现5个月的异常,1990年共和7.0级地震前出现7个月的异常,同年景泰6.2级地震前出现4个月的异常.
WANG Hualin , ZHANG Jie , LI Haiquan , YAN Nailing
1998, 20(2):93-104.
Abstract:Taking paleoearthquakes,historic and recent earthquakes as time domains,and North China,Shanxi seismic zone,Hebei plain seismic zone and Tancheng-Lujiang seismic zone as units,authors analyze and study the recurrence intervals and migration characters of great earthquakes in North China.On this basis,a dynamic problem of seismic activity,block frame motion,earthquake migration and seismicity trend in North China are discussed.
Sopyright:China Earthquake Engineering Journal