Abstract:Seismic wave is a non-stationary signal,which can not be analyzed comprehensively by classical Fourier transform because of the lack of local information.To non-stationary signal,time-frequency analysis is a powerful analysis tool.In this article,the short time Fourier transform,S transform,Choi-Williams distribution and Zhao-Atlas-Mark distribution are introduced briefly.Their application results and merits demerits in distinguishing seismic waves are summarized by using the four methods to numerical examples and real seismic signals.

Abstract:Based on the observation data recorded by Gansu Seismological Network（2001-2008）,using the SAM technique for S wave splitting analysis,the 319 shear-wave splitting parameters at 7 stations are obtained in southeastern area of Gansu province.It is shown that the average polarization of fast shear-wave is consistent with the regional maximum horizontal compressional stress,it is an efficient tool to depict regional stress field.The dominant polarization direction at stations which located on active fault or cross point of some active faults is consistent with the strike of main earthquake-controlling fault.However,for some stations the fast S wave polarization directions are not consistent with the fault strikes and the direction of regional maximum horizontal compresstional stress,probably owing to the influence of local complicated crustal structure.

Abstract:Based on digital seismograms recorded by Zipingpu reservoir digital seismic network and YZP station of Chengdu Digital Tele-seismic Network from August 2004 to May 2008 before Wenchuan MS8.0 earthquake,the seismic source parameters of 261 earthquakes above M 1.6 are calcalated.The result shows： seismic moments Mo were 1.35×1012~5.98×1014 N·m;the stess drop increased with earthquake magnitude;and the relationship of corner frequency relying on seismic moment and earthquake magnitude was not come into existence in Zipingpu reservoir area.This may have relation with augment of pressure,pervasion and infiltration of water along Longmenshan fault belt after reservoir sluice.

Abstract:The geometric and kinematics characteristics,activity segmentation and seismic risk of northern piedmont fault of Changling mountain in Gulang county,Gansu province are studied through the field investigation,trench excavation and b-value calculation.The results show that the northern piedmont fault of Changlin mountain can be divided into four secondary faults,distributes as an inverse ＂S＂ style in whole,and was active in early and middle stage of Holocene.For the latest motions,f1 at west acted as normal fault with left-lateral moving inclined to south,section f2 at west and section f3 at middle segment acted as normal fault with left-lateral moving inclined to north,while east segment f4 acted as normal fault inclined to south again.The west end of the fault is partitioned with Gulang fault by Qinjiadashan mountain and Tertiary fold system,and the east end of the fault is partitioned with Guanguanling fault by Baidunzi left-lateral pull-apart basin with step distance of 3.5 km.Due to the elapsed time of the last seismic action being very long and the modern stress quick accumulation,the fault area has high seismic risk in future time.

Abstract:The northern region of Qinghai-Xizang plateau is divided into four separated seismicity areas according to the regional geological structures,stress field and dynamic environment,they are Qilian mountain seismic belt,southeastern Gansu province,Caidam-Gonghe block and Kuma seismic belt.The starting times for the minimum earthquake magnitude with complete recording catalogue in every areas are confirmed on the base of b-value and seismic frequency.The alternative characteristics of active and calm periods for moderate-strong earthquakes in each area are concluded.Finally,the quantitatively characteristic parameters of earthquakes activity which have magnitudes bigger than moderate-strong event in average,active and calm periods are calculated separately,and also the state parameters of small event activity in three periods are obtained for the four areas.

Abstract:Based on the comprehensive research on geological structure,tectonic motion strength,history strong earthquake activity,crustal shorten velocity and local stress field characters,the northern Xinijang region is divided into five tectonic regions,they are Altai seismic belt,Urumqi tectonic region,western segment of northern Tianshan mountain,central part of Tianshan mountain and eastern segment of Tianshan mountain.By calculating the mean value of strain energy release,converting magnitude,annual occurrence rate with different magnitudes,b value and parameter m of strain accelerating release model etc.,the seismicity state of each tectonic region are analyzed quantitatively,and the character index of activity state in every tectonic regions are obtained.It may offer the quantitative criteria for seismic trend analysis and judgment.

Abstract:According to the textual research on the historical earthquake records about Hongyapu earthquake in 1609 and field surveying result of castle and wall in Hongyapu,Qingshuipu and Suzhou,it is considered that the extremely seismic area of the event located between Hongyazi and Jinfosi,the intensity was Ⅹ,magnitude reached about 7.25,the direction of long axis of isoseismal lines are NWW.We also emend three incorrect records in historical data.

Abstract:Based on the comprehensive explanation of controllable source audio frequency geo-magnetic sounding and previous geophysical prospecting data as gravity,earthquake,geo-magnetic sounding and direct current electric sounding,the tectonic framework of uplift with depression and features of Xining basin are obtained.According to distribution character of geothermal field,the geothermal reservoir type of Xining basin is discussed.It is indicated that the Xining depression in Xining basin is extensional and transtensile fault depression,characterized by higher geothermal field and geothermal gradient,it has both geothermal reservoir of fracture convection type and basin conduction type.While Datong and Pingan depression in Xining basin are compress-shear depressions,characterized by lower geothermal field and geothermal gradient,with reservior of basin conduction type.Xining depression is a favourable exploring region for geothermal resource.

Abstract:Using the MATLAB artificial neural network toolbox to establish BP neural network model based on Bayesian regularization algorithm,a method of earthquake damage prediction for multistory masonry building based on the survey data of earthquake damage from earthquake events is proposed.The input earthquake damage factors include building story number,construction quality and house integrity.The output value is building＇s destructiveness under seismic action.The result shows that the method can predict earthquake damage of multistory masonry building with good achievement.

Abstract:The earthquake corresponding relevancy spectrum（ECRS） method which based on multiple seismic parameters has been used in earthquake prediction in Xinjiang region for a certain extent in recent years.In order to test the efficency of ECRS method,a software ECRS1.0 for analyzed anomaly of ECRS is developed in this paper,according to the defining and anomaly identifying method of ECRS,and is applied in real earthquake cases.The result shows that the comprehensive precursor anomaly information for many seismic parameters can be extracted by this method adequately.In Xinjiang region,the high value area of anomaly appears before most moderate-strong earthquakes around epicentre within half-year to 1.5 year,spreads and strengthens to epicentre area gradually before event coming,and disappears or turns to low value after event in half-year to two years.

Abstract:Based on the scatter model（Sato）,using earthquake wave form data with ML≥ 2.0 from 2000 to 2008 recorded by Sheyang and Hai＇an seismic stations in the coastal areas of central Jiangsu province,the Qc values of coda with different lapse time in this region is calculated.The result indicates that this region has low Qc value,and the Qc values increase with lapse time increasing.Before Dongtai ML4.1 earthquake swarm in November,2006 and Xiangshui ML4.0 earthquake on May 6,2007,the Qc values of coda increased apparently.

Abstract:Paking array in Lanzhou Earth Observatary obtained ten groups of 3-directions strong ground motion records from the main shock of great Wenchuan earthquake.Based on the records the acceleration time history and characteristics of ground motion in loess site are studied.The result shows that peak ground acceleration（PGA） at different point in a small area of same site,with same seismic source and epicentral distance,had a certain degree of difference which obviously effected by site topography.In all ten strong motion observation points,PGA in EW direction were largest and PGA in the vertical direction were smallest.The difference of Fourier spectra in different points,especially for frequencies less than 1 Hz,is insignificant.

Abstract:Ningqiang MS5.7 Earthquake on May 27,2008,was the largest one in nearly 304 years in Shaanxi provience.Seven days before the earthquake,the data of vertical pendulum,plumbing instrument and extensometer all showed short-term anomalies at Ankang,Baoji,Ningshan and Xi′an stations.The trend of abnormal shape turned point in 2~7 days.Abnormal region lies between two fault belts,which are Lueyang-Yangxian fault and Zhushan fault in south,and Weihe fault in north.The epicenter distances 230~340 km.

Abstract:Strong earthquakes often occurred in Taiwan and northweatern regions in China.The corresponding and symmetry relation of the seismicity in recent 100 years between two regions is discussed using mathematical statistics method.The results show that the probability of MS≥6.0 earthquakes in the northwestern region is 95.08% in two years after MS≥6.0 earthquakes in Taiwan region.The time interval among MS≥7.0 earthquakes with 90% confidence degree were 2~4 years for both regions.There is no obvious difference in distribution of time interval of MS≥7.0 earthquakes for two regions by analyzing corresponding relationship between seismicity of two regions.

Abstract:In the field of earth science research,finite element method has long been deemed as one of the most important analysis tools.In this paper several main-stream fault-simulation approaches are summarized when international scholars conduct scientific researches in geosciences,especially in seismology and crustal geomorphology using continuum-based numerical method and finite element method,their relevant progress in geosciences are expounded.Generally speaking,the simulation models of geological faults can be categorized into four types： weak zone model,split node model,contact model,and block model.

Abstract:The research on river terrace,one of the most important topic in Geomorphology,is mainly focused on terrace age and genesis model.Considering both the status of research on river terrace at home and abroad,the research history of the terrace is reviewed,and four stages and features of the reaearch are summarized.

Abstract:In recent years,many subway-tunnel engineerings have being built in big cities of China for solving traffic crowd problem,but also met some engineering environment problems in building.In this paper,the researches on dynamic response theory of soil and test of dynamic properties of silty soil under subway loading,as well as long-term settlement of subway-tunnel in home and abroad are introduced in detail.The current problems in research of silty soil under cyclic loading from subway are analyzed and summarized.The development trend of the research in future are pointed out also.

Abstract:Based on the analysis of tectonic background of Xingtai MS7.2 earthquake in 1966,the range of Xingtai shock window is determined and the data of earthquake are selected.The predicting value of seismic high frequency anomaly in this shock window for M≥6.0 earthquakes in north China are analyzed and calculated.It is found that the high frequency anomaly showed better assessment of prediction efficiency.