2011, 33(4):313-318.
Abstract:A new numerical simulation method with convolutional algorithm for elastic waves propagation in heterogeneous two-phase media is derived from the convolutional differential simulation for the propagation in homogeneous media,and the second-order Biot wave equation is expressed as first-order velocity-stress hyperbolic equations,in which the unknown wavefield vectors are velocity and stress components in both fluid and solid phases.The temporal term in the wave equation is computed by stager-grid finite difference method and the spatial term is computed by the new convolutional differentiator.The wavefield characters of heterogeneous two-phase media are studied in both single and two-layered models.The results show that on the subsurface in the two-layered model,two types of fast P-wave and one type of S-wave can be observed when seismic wave is reflected,meanwhile in the media with large attenuation coefficient the slow P-wave is hard to be observed.
WANG?Yan , LIU?Jun-min , WANG?Xiao-ming , WANG?Hai-jun , TANG?Heng-zhuan , LI?Liang , TANG?Wei
2011, 33(4):319-321.
Abstract:Threshold Monitoring(TM) is a method of using real-time seismic data to evaluate the monitoring capability of Seismic network.After preprocessing seismic stations' data,short-term average(STA) instead of signal's amplitude is used for calculating events' magnitude,but it can product bias error.In this paper a method for calculating seismic station's parameters of TM system is researched,and magnitude's correction coefficents for parts of seismic stations in Xinjiang region are calculated,using the historical event records to choose the optimal frequency band for calculating the difference between log(A/T) and log(STA) in each stations.A correction table for these stations and evaluation of the monitoring capability including these magnitude's corrections are reasonable.
ZHANG?Yong-zhi , XU?Hai-jun , WANG?Wei-dong , LIU?Jie , SHAN?Feng
2011, 33(4):322-325.
Abstract:Weihe Basin is a typical fault basin,and is one of the strong underground fissures and ground subsidence regions in China.In this study,by using the particle swarm optimization algorithm combined with the dislocation model.The three dimension slip velocity of main faults are computed in Weihe Basin by using GPS data observed from 2004 to 2007.The results show that(1) characteristics of faults activity are consistent with geological results basically,except Hancheng-Huaxian opening fault,all other faults are normal dip faults;(2) the slip velocity of Qinling northern margin fault is the largest,about 4.5 mm/a,and that of Guguan-Baoji fault is the smallest,about 1 mm/a;(3) the activity of faults are strongest in EW direction,moderate in NE direction and weakest in NW direction.The characteristics of distribution is stronger in southern area and weak in northern area of the basin.
WANG?Yan-ping , LIU?Wen-tang , ZHAO?Yong-an
2011, 33(4):326-330.
Abstract:The disaster relief transportation after a large earthquake need to be not only without delay but also adequate.Based on Layer Splicing,this paper presented a scheme of structure about Multi-start(start from several sites) Earthquake Rescue Transportation System,which can mine the potential of actual post-earthquake traffic network adequately,and avoid traffic jam caused by several transportation lines from several sites.Furthermore it can even satisfy the requirements to transportation volume.
SUN?Chong-shao , MIN?Xiang-yi , ZHOU?Min-du
2011, 33(4):331-335.
Abstract:Based on seven strong aftershock accelerograms recorded by three mobile stations installed on the top,half way and foot of a small hill respectively near Wenxian county town after the great Wenchuan earthquake,through adjusting the reference line of the records and calculating the root-mean-square(RMS) of the records,the influence of the local topography on ground motion during strong shocks are studied.The result shows that the isolated-protruding topography has obviously amplifying action to the ground motion acceleration.So it is necessary to evaluate the influence of local topography on ground motion during strong shocks in urban and town planning.
LIU?Peng , ZHENG?Kai-feng , YANG?Lei , WU?Zhen-wang
2011, 33(4):336-341.
Abstract:The beam-shear key pounding effect is the direct factor to cause shear key of a bridge damage.In order to quantitatively analyze the change of bridge transverse seismic response caused by collision,the Kelvin contact element model and the SSH numerical calculation method are used to derive the numerical calculation method and procedure for bridge transverse seismic response considering the beam-shear key pounding effect.And MATLAB language is used to develop the computer program.According to the comparison of calculational result and test result obtained by reference,it shows that the proposed method is computationally efficient and accurate.A example is given to introduce the practicability of the proposed method.
SHI?Zhi-gang , LEI?Zhong-sheng , YUAN?Dao-yang , LIU?Xing-wang
2011, 33(4):342-348.
Abstract:According to the results of renewly checked historical earthquake data and field investigation to 1306 Guyuan earthquake in Ningxia Hui Autonomous Region,we delineated that the area damaged seriously by the earthquake(Ⅷ intensity) is located in the zone which involve Guyuan,Kaicheng and Chaona.The meizoseismal area(Ⅸ~Ⅹ intensity) is near Kaicheng of Guyuan countytwon,and magnitude of the event was about M7.The direction of the long axis of the area damaged seriously is NNW,and it is basically consistent with the Guyuan-Heshangpu segment of the Liupanshan eastern piedmont fault.This fault segment is active sinistral reverse fault in Holocene,locally preserves the remnants which is similar to the earthquake rupture zone and has the paleoseismic section.We concluded that this segment fault is relative to the 1306 Guyuan earthquake.
WANG?Zhi-jie , LUO?Ya-sheng , TAN?Dong-yue , LI?Hao-dong
2011, 33(4):349-353.
Abstract:Dry density is an important controlling index of the geotechnical engineering constructions.With different dry densities and different initial average principal stresses,the dynamic torsional shear triaxial tests are carried out on remodeled loess under the condition of pre-shearing stress,which is produced by rotation of principal stress axes(α0=45°).Research results show that the dry density has little effect on the dynamic shear modulu of remodeled loess under the condition of pre-shearing stress.Initial average principal stress has some certain effect on the modulu.If other conditions being the same,the dynamic shear modulu and initial dynamic shear modulu increase with the increase of dry density and initial average principal stress.The damping ratios of remodeled loess first decrease with the increase of the dynamic shear strain and then increase gradually.The effects of dry density and initial average principal stress on damping ratio of remodeled loess are insignificant.
XU?Shun-hua , WANG?Lan-min , WANG?Qiang , YUAN?Zhong-xia
2011, 33(4):354-358,385.
Abstract:Wudu is the area where using typical rammed earth rural houses in Gansu province.In experiments two wall specimens are built using local material and local construction technology,and the shearing strength of wall is investegated by pseudo-static test,the results show(1) the overlying load on the wall has greater effect on horizontal load capacity and deformation of the wall,with the overlying load from 10 kN to 18 kN,cracking load and ultimate load increased by 217% and 359%,ultimate top displacement is reduced by 30%;(2) the rammed earth wall is always destroyed along the horizontal and vertical contacts between layers,and eventually is fragmented into blocks with the role of horizontal cyclic loading.At last,this paper recommend to reinforce the rammed earth bearing wall of the existing rural houses with iron mesh.
2011, 33(4):359-362.
Abstract:In recent years,CCD technology has been developed very mature and applicated in wide range.In this paper the development of high precision water pipe inclinometer based on CCD is introduced.Using the contactless measurement method,the system reduces the effect of the float interference on measurement precision.It has a small size,is covenient in installation,can be used in mobile observation.
CHEN?Wen-kai , HE?Shao-lin , ZHANG?Su-ping , ZHOU?Zhong-hong
2011, 33(4):363-369.
Abstract:The great Wenchuan earthquake in 2008 induced a large number of secondary mountain hazards.In this paper,the earthquake-induced mountain hazards in Wenxian County,Gansu province,are interpreted using the image enhancement technology and human-computer interaction technology based on the multi-type and multi-temporal remote sensing images(TM,ASTER,SPOT,etc.) and the geoscience knowledge.Based on GIS spatial analysis function,the analysis of the relationship between mountain disaster and elevation,slope,vegetation coverage and earthquake intensity,as well as the rules of development and distribution of mountain disaster reveals the following characteristics in the study area.The geo-hazard mainly generated in the slope varying from 20 to 60 degrees,mainly occur in slopes with the altitude from 1 000 m to 2 500 m;developed in the area where the earthquake intensity is Ⅶ or exceeding Ⅶ.The result should be significant in reconstruction.
SHI?Hai-kuo , ZHU?Xin-yun , HE?Yong-zhong , ZHANG?Li-heng
2011, 33(4):370-375.
Abstract:Based on the Aki model,adopting 82 digital wave datas of earthquake with ML≥2.0 from January,2008 to December,2009,which were recorded by Ningxia earthquake network,the average Q values of seismic coda in Ningxia and adjacent region are calculated,and the relationship between Q value and frequency is polyfited.The whole region's result is Q(f)=(212±87.62)·f0.7584±0.19.Compared with other domestic regions,the Q value of seismic coda is relatively lower,but the dependence on frequency is higher.According to the regional seismic geology,tectonic characteristics and the homochronous seismic activity,the research region is divided into four concentrated minor-earthquake areas: Ji Lantai,Yin Chuan,Wei Ningtong and Gu Hai,and the Q values of four regions are counted.Comparison shows that Q values of seismic coda reflects the characteristics of seismicity in each area.
ZHAO?Zhen-shen , ZHANG?Hui , SU?He-jun
2011, 33(4):376-379.
Abstract:According to the forming mechanism of soil gases above faults,the abnormal geochemical features of mercury and radon on Maqu active fault are analyzed.The position,occurrence and mechanical property of Maqu active fault are determined by the abnormal geochemical features,and which are consistant with the scale and characters of the fault from the fault section.The conclusions provided a useful reference for active faults evalution.
LI?Gang , ZHOU?Li-xia , WANG?Xiao-lei , QI?Shi-chao , YAO?Hui-qin , SUN?Jing-yan
2011, 33(4):380-385.
Abstract:Using the Open Source Systems such as Nagios,Cacti,NagVis,an Operation Monitoring System has been developed in the Industry Network of Earthquake Administration of Tianjin.It can focus on monitoring various types of network equipment,instruments and services.It achieves the failure alarm system in the network with the duty system linkage,and improves ability of the overall operation monitoring as well as response abilit to failures.
MA?Dong , FENG?Xiang-dong , ZHANG?Su-xin , WANG?Xiao-shan , LI?Jun-liang , WANG?Xiang
2011, 33(4):386-391.
Abstract:On July 30,2010,ML3.8 and ML3.3 earthquakes occurred in Yixian,Hebei province.The epicenters were located about 7 kilometers from the Yixian seismic station.The stations around the epicentres mainly are deformation stations.Although magnitude of Yixian earthquakes are small,but there were co-seismic responses in 12 observation items,that is outstanding case for moderate-small earthquakes.The earthquakes are relocated according to seismic waveform data from seismic network of Hebei province.The focal mechanism solutions according to both the rapid report directory and the relocation result.The trends of focal fault of two earthquakes are NEE,and the nature of the fault are positive and right-lateral strike-slip.
2011, 33(4):392-402.
Abstract:In recent years,the "earthquake early warning"(EEW) technology has been developed rapidly around the world,some cases show that EEW has successfully provided seismic early warning information and got earthquake disaster mitigation effectiveness.In this paper,the approaches of the EEW,including front wave detection,using the P wave,onsite warning and regional warning are introduced,and the applications of EEW in Mexico,Japan,Turkey,China Taiwan,Romania and other countries and region areas are introduced also.Some problems and challenge in the earthquake early warning,as well as its perspective are analyzed.
ZHAO?Jun-juan , LI?Cheng-fan , YIN?Jing-yuan , ZHANG?Gui-fang , SHAN?Xin-jian
2011, 33(4):403-407.
Abstract:Among many radar targets,artificial corner reflectors construction is a special kind of scatter construction.In this paper,the basic conceptions of artificial corner reflector technique in interferometer synthetic aperture radar(CR-InSAR) are introduced,the features of common used dihedral corner,triangular pyramidal trihedral corner,cubic trihedral corner and rectangle trihedral corner reflectors and their radar cross section(RCS) computer simulation are expetiated.Finally,the major area of application and some problems which are in the production and erection process of artificial corner reflectors are discussed.
2011, 33(4):408-412.
Abstract:Using present deformation monitoring equipments and technique means,in order to avoid various interference factors and provide reliable precursor information for earthquake forecasting,a new way for deformation monitoring is presented in this paper.The new method consists of three parts,the first is to take acting force as deformation observation aim;the second is to changes spotting way of seismic station from independent observation in each station to station group concentrating observation;the third is to adjust spotting way of the FSQ water tube tilt-meter and SSY quatz tilt-meter from relative observation in single direction to absolute observation for same point using both equipments.
Sopyright:China Earthquake Engineering Journal