• Volume 34,Issue 1,2012 Table of Contents
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    • Multi-method Linked to Study Future Seismic Tendency

      2012, 34(1):1-9.

      Abstract (783) HTML (0) PDF 596.81 K (1061) Comment (0) Favorites

      Abstract:Several earthquake precursory methods are combined to investigate the future large earthquake potential in the research region.First the Pattern Informatics(PI) method is used to quantify localized changes surrounding the epicenters of large earthquakes and to objectively quantify the anomalous areas(hot spots) of the upcoming events.Then the seismogenic regions of the ensuing large events are delineated by integrating with associated active fault zones.Finally,the earthquake potential in the region is evaluated using 3 other short-to-intermediate-term earthquake prediction methods(Load Unload Response Ratio,State Vector,and Accelerate Moment Release).In the spatial scale the approach can achieve the gradual approximation to the seismogenic zones;while in the temporal scale,the approach can achieve the natural transition from the long term to the short-to-intermediate-term earthquake forecast.As a retrospective study,the large earthquakes(ML6.5) occurred in western China in last 3 years are examined.The results may suggest that,rather than a single precursory method,the multi-methods combined approach can be a useful tool to provide stronger constraints on forecasts of future large events.

    • Study on the t-D Earthquake Location Method

      2012, 34(1):10-13.

      Abstract (769) HTML (0) PDF 530.04 K (1092) Comment (0) Favorites

      Abstract:By the locating method study using the micro-seismic data of portable seismic array observation in the southeast area of Gansu province,a location approach of t-D based on global grid search is proposed.Earthquakes located by this method which do not need to set up velocity model,compared to conventional location method,their positioning are basically same in epicenter location,and have higher resolution in focal depth.

    • Delaunay Triangulation Interpolation Algorithm and Its Application on MT Mapping

      2012, 34(1):14-17.

      Abstract (838) HTML (0) PDF 304.94 K (1446) Comment (0) Favorites

      Abstract:A rapid two-dimensional linear interpolation algorithm based on the Delaunay triangulation for magnetotelluric(MT) inversion process is researched and implemented,and is applied to the data griding in real-time imaging of MT inversion.The result of using the algorithm in true case shows that the algorithm is stable,fast with good interpolation effect,and is easy for simulating topographical data.It can meet the needs of real-time imaging in MT inversion.

    • Theoretical Calculation for the Signal Noise Ratio of the Underground Electric Resistivity Observation in the Two-layered Horizontal Homogeneous Medium

      2012, 34(1):18-22,104.

      Abstract (828) HTML (0) PDF 398.13 K (1212) Comment (0) Favorites

      Abstract:In the model of homogeneous medium of two horizontal layers,the effect caused by disturb current on surface when observing the geo-electric resistivity in different geo-electric sections is calculated.The result shows that the effect caused by disturb current is determined by the type and parameters of geo-electric section,the distance from electrodes to disturb current and the depth of electrodes.The result of this article may be used as a reference when choosing the electric structure under stations,determining the depth of electrodes and escaping from disturb current.

    • Relation between the Source Rupture Process and Surface Rupture Zone of the M_S7.1 Yushu Earthquake

      2012, 34(1):23-28.

      Abstract (796) HTML (0) PDF 976.10 K (810) Comment (0) Favorites

      Abstract:Based on the digital teleseismic P-wave seismograms recorded by 15 long-period seismograph stations of the global seismic network,source rupture process of the April 14,2010 Yushu MS=7.1 earthquake is studied by a inversion method,and compared with surface rupture zone which was investigated after the earthquake.The result shows that the earthquake is a unilateral rupture event on the whole.The source rupture initiated at the hypocenter(33.2°N,96.6°E,focal depth 10 km),and propagated to the southeast at first.The rupture broken though the ground surface departed from 20 km of the epicenter,it extended 50 km along strike,the maximal slip is 2 m.These results are coincide with the investigated feature of the surface rupture zone.

    • Monte Carlo Simulation of System Reliability of Gravity Retaining Wall

      2012, 34(1):29-32.

      Abstract (760) HTML (0) PDF 237.68 K (1066) Comment (0) Favorites

      Abstract:A model is formulated for calculating the reliability of gravity retaining wall corresponding to such failure mode as overturning,base sliding,insufficient bearing capacity of foundation and tensile strength of the wall,and a gradual equivalent method is employed to calculate the reliability of the structural system.The design parameters are assumed to be random variables with normal distribution,the random sample is extracted by using MATLAB library function normrnd.The reliability of several monadic failure modes and the reliability of the structural system are calculated by selecting a real retrofitted gravity retaining wall as numerical example and the result is compared with the theoretical analysis results made by author.The result shows that the reliability calculated from the two methods are consistent.

    • Study of Seismic Response Influence Parameters on Damping Connective Structure

      2012, 34(1):33-38.

      Abstract (843) HTML (0) PDF 373.68 K (1144) Comment (0) Favorites

      Abstract:Aimed to damping connective structure,using series-parallel particles layer model,along the connected-building direction put the El Centro1940 seismic wave for the structure,the influence on seismic response is discussed while the natural vibration period ratio of adjacent structures and damping stiffness of connective structure are changed.Research results show that the natural vibration period ratio of adjacent structures and damping stiffness of connective structure have a greater impact for the seismic response of the damping connective structure,on the other hand,there is a period ratios and damping stiffness which make the seismic response to optimal.The result provide some reference to the practical application and research.

    • Discussion on the Prediction of the Yushu M_S7.1 Earthquake in Qinghai Province in 2010

      2012, 34(1):39-43.

      Abstract (718) HTML (0) PDF 312.85 K (1102) Comment (0) Favorites

      Abstract:The source combination model of the Yushu MS7.1 earthquake in Qinghai province on April 14,2010 is discussed.Using the view point of slowing down in critics the foreshocks before the Yushu earthquake are identified in some sense.The occurrence date prediction of the Yushu earthquake is suggested to be determined by the methods of "rhythm of multiplied nine days in different years" and the "two times of magnetic storm".

    • Estimation of Casualty in Strong Earthquake Using Empirical Regression Method

      2012, 34(1):44-49.

      Abstract (741) HTML (0) PDF 383.25 K (1082) Comment (0) Favorites

      Abstract:Based on the review of researches on several models for earthquake casualty estimation in recent years,according to the empirical estimation model of PAGER system which is released by USGS in October,2007,two regional applicable earthquake casualty estimation models are developed using the loss records of 128 earthquakes from 1970 to 2008 in China.And using 234 earthquakes occurred from 1980 to 2007,a linear regression relationship between the number of the seriously injured and the number of death caused by earthquakes is established.At last,by comparing the estimation of casualty using the models with the actual number of victims in 2008 Wenchuan earthquake,it is proved that the model can make approximate estimation.

    • Discussion on the Late Quaternary Activity and Earthquake Risk Potential of Longquanshan Fault in Sichuan

      2012, 34(1):50-56.

      Abstract (811) HTML (0) PDF 841.44 K (2730) Comment (0) Favorites

      Abstract:The Longquanshan fault zone is a regional fault which is located between strongly concaved block of western Sichuan basin and stably uplifted block of middle Sichuan.After the Wenchuan earthquake in 2008,the earthquake risk potential of this fault has been greatly concerned.In this paper,the distribution,late Quaternary activity,deep structure and formation mechanism of Longquanshan fault zone are discussed.It's possible that the north segment section of Longquanshan fault zone is distributed along the west side of Lonquanshan mountain at east of Deyang city.The fault emerges in both wings of anticline on the middle segment of the fault;and the south segment of the fault is mainly W-dipping.The fault has been active since Late Pleistocene.The previous terrace investigation demonstrated that the fault zone even actived in Holocene.Considering the evaluating the earthquake risk potential of this fault,further investigationg on the activity time,deep structure and movement mode of the fault zone is deserved to be done.

    • Research on the Characteristics of Recent Focal Mechanism Solution and Seismic Activity in Xinjiang Area

      2012, 34(1):57-63.

      Abstract (723) HTML (0) PDF 698.99 K (1100) Comment (0) Favorites

      Abstract:The focal mechanism solutions and the distribution characteristic of 88 moderate-strong earthquakes in Xinjiang and its adjacent area from 2003 to 2009 are analyzed.The related discussion is given combining with the seismic activity characteristics and the region stress field in the same period.The result shows that stress field in Xinjiang area is mainly controlled by level pressure stress in NNW direction in this period,with certain difference from the principal compress stress P axis distribution in NNE from 1990 to 2002.The seismogenic faults of moderate-strong earthquakes exist certain multiplicity,it demonstrates the complexity of tectonic movement in Xinjiang area.The elevation angle′s change of principal compression stress P axis is related with alternation of strong and the weak of seismic activity.In the research time,the spatial distribution with different magnitude earthquakes have obvious level characteristic.

    • Quaternary Active Features of the NW-striking Fault Zone in Jiulong River Downstream Area,Fujian Province

      2012, 34(1):64-71.

      Abstract (794) HTML (0) PDF 471.38 K (1152) Comment (0) Favorites

      Abstract:The Quaternary active features and combination relation of NW-striking fault zone in the downstream area of Jiulongjiang in Fujian province are researched through analysis of Quaternary geology,geomorphology,high-resolution seismic profiling,dating and drilling.The results show that:(1) The Guokeng-Jiangdong fault(F1),Zhukeng fault(F3) and Jinfeng-Damaoshan fault(F7) actived in early Quaternary(Q1-2).Daishanyan-Hengkeng fault(F6) actived in early Quaternary and late Pleistocene on different segments.The Fuchuangshan-Kangshan fault(F4) and Jiulongjiang(west stream) fault(F5) actived in early late Pleistocene.The Haicang-Qiangyu fault(F2) actived in late Pleistocene.(2) The Guokeng-Jiangdongqiao fault and the Jinfeng-Damaoshan fault divided the research area into 3 blocks and formed the Structural Assemblage of Xiaotiankeng horst,Zhangzhou graben and Guojianshan horst.Than the Zhangzhou graben was divided into 3 blocks by the Fuchuanshan-Kangshan fault and the Daishanyan-Hengkeng fault,and formed the smaller Structural Assemblage of Yuanshan horst,Jiulongjiang Xixi valley graben and Maanshan horst.

    • Textural Research of Zhangye-Jiuquan Earthquake in 756 A.D.

      2012, 34(1):72-77.

      Abstract (958) HTML (0) PDF 417.36 K (1309) Comment (0) Favorites

      Abstract:On the basis of present and newly added historical earthquake data,we suggest that the parameters of Zhangye-Jiuquan earthquake in 756 A.D.drawn from the present earthquake catalogs are not definite and amendments should be made.The magnitude of this earthquake should be amended from 6 to about 7,the epicenter intensity should be amended from Ⅶ~Ⅷ to Ⅸ~Ⅹ,and the heavily-damaged area of this earthquake should be located near Luocheng,northern of Gaotai county town.

    • Study on the Seismic Fortification Parameters in the Loess Plateau of Eastern Gansu Province

      2012, 34(1):78-83.

      Abstract (800) HTML (0) PDF 1005.70 K (1069) Comment (0) Favorites

      Abstract:The feature of earthquake ground motion parameters of loess plateau in the eastern Gansu province are analyzed on the basis of geological tectonic environment,historic earthquake influence,building damaging features and earthquake risk probability calculation.The amplification factor and landform zoning of the seismic parameters are studied by the seismic response analysis of loess site and topography characters.The research shows that the earthquake impact is mainly caused by strong earthquake from long distance and the earthquake duration time of ground motion is longer in which the long-period component is abundant.The thick loess and landform have significant amplification to the earthquake ground motion and the seismic parameters have landform zoning behavior.Comparison with the seismic ground motion parameter zonation map,some suggestions to the seismic fortification parameters are proposed for the loess plateau in eastern Gansu province.

    • Distribution Characteristics of Wave Velocity Ratio and Poisson's Ratio in Handan-Xingtai Areas,Hebei Province

      2012, 34(1):84-87.

      Abstract (822) HTML (0) PDF 232.29 K (1337) Comment (0) Favorites

      Abstract:According to multi-station Wadati diagram method,using the data from 9 digital seismic stations in Handan-Xingtai region of Hebei province,the distribution characteristics of wave velocity ratio and Poisson's ratio values in this region are studied.The results show:(1) In 9 sub-regions,velocity ratio values are between 1.696~1.737,the correlation coefficients are among 0.988 3~0.999 1,the average velocity ratio value of the study area is 1.719,the average Poisson's ratio is 0.244.The Poisson's ratio result consistent with the crust medium which mainly consist of granite in the study area.(2) The wave velocity ratio values and d Poisson's ratio values vary in complex image in the study area.It objectively reflect the different medium properties of the upper crust and the complicated nature of geological structure under the study area.

    • Preliminary Study on the Minimum Distance between Strong Motion Station and Interference Sources

      2012, 34(1):88-92.

      Abstract (767) HTML (0) PDF 316.76 K (1078) Comment (0) Favorites

      Abstract:In order to provide quantitative reference for avoiding interference sources such as pump,train station and quarry blasting in strong motion station establishing and station environmental protection work,some tests on site are done and the vibration attenuation relationships of these three interference sources are discussed.The studies suggest that the distance from the station for early warning and fixed observation to pump should be more than 69 m,to train line(low-speed for passenger and freight) should be more than 228 m,and to quarry should be more than 723 m.The distance from the station for quick report to pump should be more than 19 m,to train line should be more than 156 m,and to quarry should be 428 m.

    • Integrality Analysis of the Earthquake Catalog for Hohhot-Baotou Area in Inner Mongolia

      2012, 34(1):93-98.

      Abstract (726) HTML (0) PDF 676.09 K (1136) Comment (0) Favorites

      Abstract:Taking the Hohhot-Baotou region(40° ~ 42°N,108°~ 114°E) in Central Inner Mongolia as study area,collecting the earthquake events with ML≥1.0 from January 1,2001 to April 30,2010,the number of seismic samples is sliding scaned and the minimum integrality magnitude Mc is calculated.The Mc change curve with time is drawn also.It is considered that Mc change along with the time is mainly reflected by monitoring capabilities of earthquake station network and seismic activities,but the station layout、the earthquake noise ratio and human factors can also cause short-term or discontinuous Mc change.Meanwhile in two assumptions made by Rydelek,the completeness of earthquake catalog in Hohhot-Baotou area is tested by RS method.The tested result is consistent with our Mc value,and also with the monitoring magnitude range obtained from the monitoring ability of local network.So the study result can truly reflect the integrality of earthquake catalog in Hohhot-Baotou area since 2001.

    • Study on PGA Attenuation of Three Strong Aftershocks of 2008 Wenchuan Earthquake

      2012, 34(1):99-104.

      Abstract (749) HTML (0) PDF 372.66 K (1050) Comment (0) Favorites

      Abstract:Using the data of three strong aftershocks after the 2008 Wenchuan earthquake recorded by Gansu strong motion stations,the free field acceleration attenuation in southern Gansu province are studied.The attenuation of Peak Ground Acceleration(PGA) with the epicentral distance follows the exponential law,and the forms of attenuation are parallel.However,the attenuation index of three strong aftershocks also has some differences.The condition of the strong motion stations has certain influence to ground motion intensity and frequency spectrum.So further research to get the universal attenuation law of strong earthquakes in southern Gansu province is needed.

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