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Relocation of Microearthquakes in beijing and Its Neighboring Areas and Its Tectonic Implications

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Earthquake Research in china 1996年第1期10卷 42-50页

作者： Wang Suyun,Xu Zhonghuai,Yu Yanxiang,and Huan Wenlininstitute of geophysics,SSB,{2. {3.,china

The 3.8 microearthquakes that occurred in beijing and its neighboring areas(3.°-41°,114°-117°E)during 1979 to March of 1992.are relocated in this *** of hypocenter locations is improved by rechecking and supplementing readings of arriving times of the seismic phases used,testing and selecting the appropriate crustal model,and modifying the computer *** the relocation,the number of earthquakes with focal depth determination has been increased to 3.3.from the previous *** overall average RMS residual of the observational arrival times has been reduced to 0.45±0.18 s from the previous value of 0.80±0.40 *** 10% of the relocated hypocenters,which are mostly in border regions of the area covered by the beijing Telemetered Seismic Network,have been shifted more than 10 *** of the relocated earthquakes are concentrated in the intermountainous basins,such as the Huai’an,Xuanhua,Huailai,and Zhuolu basins,and are related with the basin boundary faults between

关键词： Seismic location Focal depth Epicentral distribution Active fault

Discussion on Principles and Methods in Estimating the Maximum Potential Earthquakes in Low Seismicity Areas

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Earthquake Research in china 2000年第2期14卷 89-99页

作者： Chen Jiageng, Yan Jiaquan, Xu Guangyin and Hao Yuqininstitute of geophysics, CSB,{2.,{3. institute of geophysics CSBBeijing 100081China

Five principles and methods are proposed for estimating the maximum potential earthquakesin low seismicity areas,and their applicabilities are discussed,taking Sichuan basin as asample *** proposed principles and methods are not only on the grounds of thegeological tectonics but also considered fully the mutual complementation between geologicaland seismological *** will be helpful to the study of engineering seismology andthe assessment of designing ground motion parameters in low seismicity areas.

关键词： Low seismicity area Maximum potential earthquake Causative tectonics Diffusive earthquake

Mesozoic Replacement of Bottom Crust in North china Craton:anorogenic mantle-crust interaction

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Mesozoic Replacement of Bottom Crust in North China Craton:a...

中国科学院地质与地球物理研究所2.02.术年会

作者： Mingguo ZHAI~a Qicheng FAN~b Wenjun LIU~a. a.institute of Geology and geophysics,Chinese Academy of Sciences,{2. 10002. b.institute of Geology,china seismological bureau,{2. 10002.

The study of Precambrian granulite terrain in the North china craton and the granulite xenoliths in Cenozoic volcanic rocks shows that there are differences between the Precambrian lower crust and the present *** study further shows that the Mesozoic tectonic inversion in the North china craton not only causes changes in basin-range system but also changes in the composition and texture of the lower crust and upper *** have been many models suggested,such as delamination,mantle-root structure etc,for the mechanism of thinning of the eastern lithosphere,all related to the evolution of orogenic *** have noted in our work that most or all of the lowermost crust of the North china craton has been substituted by the Mesozoic lower *** has been occurred not only the edge of but also within the ***,the processes of the North china craton mantle uplifting and the quick thinning of the Paleozoic lithosphere may be seen as the replacement of bottom crust in the North china *** upwelling mantle plume possibly existed during Jurrasic-Cretaceous,and strong crust-mantle interaction is a major way of replacement of bottom crust,while the details of thermal and chemical corrosion is still not ***,it may be inferred that this has no direct relationship with the evolution of orogenic belt and is different from the lithosphere delamination at the root of orogenic belt.

关键词： Mesozoic lower crust replacement of bottom crust North china

Concordant structural variations from the surface to the base of the upper mantle in the North china Craton and its tectonic implications

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Concordant structural variations from the surface to the bas...

中国科学院地质与地球物理研究所第十届(2.10年度)学术年会

作者： Ling Chen~* seismological Laboratory(SKL-LE),institute of Geology and {2.,Chinese Academy of Sciences,{3. 10002.,china

This study presents an integrated study of the North china Craton(NCC)based on recent high-resolution seismic images combined with observations on surface geology,regional tectonics and mantle dynamics. Seismic images reveal markedly concordant and rapid variations in crustal and lithospheric structure and thickness,upper mantle anisotropy,and discontinuity structures and thickness of the mantle transition zone near the boundary between the eastern and central parts of the *** rapid variations roughly coincide with the sudden change in both surface topography and gravity field as marked by the North-South Gravity Lineament(NSGL).Such a shallow-deep structural concordance may reflect different lithospheric tectonics and mantle processes in the two domains during the Phanerozoic reactivation of the *** structural variations are particularly present to the west of the NSGL,especially between the Archean Ordos Plateau, which retains the characteristics of a typical craton,and the surrounding Cenozoic rift systems which are underlain by a significantly modified and thinned *** observations provide deep structural evidence that the Phanerozoic reactivation was not confined to the eastern NCC as previously thought,but also affected areas in the central and western NCC,though to a much lesser *** both sides of the NSGL, lithospheric modification and thinning appear to be more pronounced along Paleoproterozoic belts suturing Archean blocks,demonstrating the importance of pre-existing lithosphere-scale structures in controlling the tectonic evolution of the *** further indicates that craton reactivation probably is common given the fact that structural heterogeneities are always present in cratonic *** seismic structural images together with geological,petrological,geochemical and mineral physics data suggest that the fundamental destruction of the eastern NCC lithosphere may have been triggered largely by the deep subduction of t

关键词： North china Craton Lithospheric reactivation Concordant structural variation Pre-existing structure Pacific subduction

A COMPREHENSIVE STUDY ON LITHOSPHERIC STRUCTURE IN NORTH china

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Chinese Science Bulletin 1988年第21期33卷 1803-1807页

作者：冯锐郑书真 institute of geophysics State Seismological Bureau Beijing Geophysical Exploration Brigade State Seismological Burcau Zhengzhou

In the last three years a vast amount of new geological and geophysical data have been collected and processed in our study. Then a strict three-dimensional gravitational computation combined with seismic data has bee... 详细信息

关键词： lithospheric structure gravitational inversion North china

Structure of the crust and uppermost mantle of the Yanshan Belt and adjacent regions at the northeastern boundary of the North china Craton from Rayleigh Wave Dispersion Analysis

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Structure of the crust and uppermost mantle of the Yanshan B...

中国科学院地质与地球物理研究所2.08学术年会

作者： Qunshu Tang~*,Ling Chen~1 seismological Laboratory(SKL-LE),institute of Geology and {2.,Chinese Academy of Sciences,{3. 10002.,china

We have used Rayleigh wave dispersion analysis and inversion to produce a high resolution S-wave velocity imaging profile of the crust and uppermost mantle structure beneath the northeastern boundary regions of the North china Craton(NCC).Using waveform data from 45 broadband NCISP stations,Rayleigh wave phase velocities were measured at periods from 10 to 48 s and utilized in subsequent inversions to solve for the S-wave velocity structure from 15 km down to 12. km *** inverted lower crust and uppermost mantle velocities, about 3.75 km/s and4.3.km/s on average,are low compared with the global *** Moho was constrained in the depth range of 3.-40 km,indicating a typical crustal thickness along the ***,a thin lithosphere of no more than 100 km was imaged under a large part of the profile,decreasing to only - 60 km under the Inner Mongolian Axis(IMA) where an abnormally slow anomaly was observed below 60 km *** overall structural features of the study region resemble those of typical continental rift zones and are probably associated with the lithospheric reactivation and tectonic extension widespread in the eastern NCC during Mesozoic-Cenozoic *** high velocities,up to～4.6 km/s,were found immediately to the south of the IMA beneath the northern Yanshan Belt(YSB),extending down to>100-km *** anomalous velocities are interpreted as the cratonic lithospheric lid of the region,which may have not been affected by the Mesozoic-Cenozoic deformation process as strongly as other regions in the eastern *** on our S-wave velocity structural image and other geophysical observations,we propose a possible lithosphere-asthenosphere interaction scenario at the northeastern boundary of the *** speculate that significant undulations of the base of the lithosphere, which might have resulted from the uneven Mesozoic-Cenozoic lithospheric thinning,may induce mantle flows concentrating beneath the weak IMA *** relatively thick

关键词： Rayleigh waves North china Craton Yanshan belt Crustal and uppermost mantle structure Lithospheric reactivation

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石油微观渗流数值模拟实验

系统仿真学报 2003年第10期15卷 1477-1480页

作者：赵树贤罗晓容中国地震局地壳应力研究所北京100085 中国科学院地质与地球物理研究所北京100029

应用基于骨架隐曲面造型技术,构造了一种抽象的孔隙空间模型,在此基础上运用系统模拟技术开发了一个石油微观运移数值模拟实验平台,用于模拟和展示石油在饱含水孔隙介质中的运移过程,并验证了以浮力为主要运移动力的动力学模型的适用性。

关键词：孔隙空间石油运移物理模拟数值模拟隐曲面八叉树

geophysics and Seismic Hazard Reduction

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Science Foundation in china 2003年第2期 38-42页

作者： Yu Guihua Zhou Yuanze Yu Sheng ( institute of Geology, china {2. {3., beijing 10002. Graduate School, CA S, beijing 100085 Department of Earth Sciences, NSFC, beijing 100085)

1 Introduction to the International Research on geophysics and Seismic Hazard ReductionThe earthquake is a natural phenomenon, which often brings serious hazard to the human life and material possession. It is a physical process of releasing interior energy of the earth, which is caused by interior and outer forces in special tectonic environment in the earth, especially within the lithosphere. The earthquake only causes casualty and loss in the place where people inhabit. Seismic hazard reduction is composed of four parts as seismic prediction, hazard prevention and seismic engineering, seismic response and seismic rescuing, and rebuilding.

关键词： were of Pro de for in

Planetary wave-type oscillations in the ionosphere and their relationship to mesospheric/lower thermospheric *** disturbances at Wuhan(3..61N,114.51E)

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Planetary wave-type oscillations in the ionosphere and their...

中国科学院地质与地球物理研究所2.06学术年会

作者： J.Xiong~(a,_),W.Wan~a,B.Ning~a,L.Liu~a,Y.Gao~b a institute of Geology and geophysics,The Chinese Academy of Sciences,P.O.Box 982.,{2. 10002.,PR china b institute of geophysics,china seismological bureau,{2.,PR china

Using wind,ionospheric and geomagnetic intensity data observed simultaneously at Wuhan(3..61N,114.51E) in 2.02.and 2.03.planetary wave type oscillations(PWTO) in the ionosphere and their relationship with oscillations in the mesosphere/lower thermosphere(MLT) and geomagnetic intensity have been *** cases of 2. and 5-day oscillations in the ionosphere are analyzed to distinguish MLT drivers and geomagnetic *** geomagnetic oscillations are the most important drivers for the PWTO with dominant periods of 5-,10-, *** the planetary waves in MLT winds are the main drivers for the quasi-2.day oscillations in the *** correlation coefficient of the occurrence rates of the 2.day oscillation in winds and in ionospheric f0F2.is 0.82.for the data from February to *** oscillations in the geomagnetic intensity can drive 3.-50%of 5-,10- and 13.5-day PWTO events in the *** we evaluate all of the possible events driven by geomagnetic oscillations, more than 70%of the events have a relationship with geomagnetic oscillations with 5- and 10-day *** 3..7 h PWTO in ionospheric plasma frequencies observed from day 161 to 166 in 2.02.are generated by an upward propagating wave with period 43.8 *** events of 6-day oscillations in the ionosphere observed during May to July in 2.03.have different *** first one is probably generated by 5.4-day upward propagating waves in MLT winds,but enhanced during a moderate geomagnetic *** second one is generated by the geomagnetic oscillations during a strong geomagnetic storm,r 2.05 Elsevier *** rights reserved.

关键词： Planetary wave Ionosphere Mesosphere and lower thermosphere