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Identification　method　of　weak　seismic　phases　on　the　basis　of　wavelet　packet　trans-form

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Acta Seismologica Sinica(English Edition) 1998年第4期11卷 431-439页

作者： Xi-Qiang Liui (1) (2. Hui-Lan Zhou (1) Zhi-Zhen Zheng (3) Ping Shen (4) Xuan-Hui Yang (3) Yan-Lu Ma (1) 1. Graduate School University of Science and Technology of China 100039 Beijing China 2. seismological bureau of Shandong Province 250014 Ji’nan China 3. Center for Earthquake Data and Information China Seismological Bureau 100045 Beijing China 4. institute of geophysics China Seismological Bureau 100081 Beijing China

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关键词： wavelet transform wavelet packet transform transient spectra analysis weak seismic phase discrimination

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电力系统抗震研究概况

世界地震工程 2002年第4期18卷 79-84页

作者：李亚琦李小军刘锡荟中国地震局地球物理研究所北京100081 信息产业部电子信息中心北京100846

分析了电力系统的震害特点,概述了国内外电力系统抗震性能的研究现状,指出了一些值得注意的问题,并提出了一些研究方向。

关键词：电力系统变电站电气设备抗震性能

A thinned lithospheric image of the Tanlu Fault Zone,eastern China:Constructed from wave equation based receiver function migration

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A thinned lithospheric image of the Tanlu Fault Zone,eastern...

中国科学院地质与地球物理研究所2.06学术年会

作者： Ling Chen,Tianyu Zheng,and Weiwei Xu seismological Laboratory(SKL-LE),institute of Geology and{2.,Chinese Academy of Sciences,beijing 10002.,PR China

We apply the newly proposed wave equation-based receiver function poststack migration method to the Northern China interior Structure Project broadband data to image the lithospheric structure of the Tanlu Fault Zone area in eastern *** migration result reveals a 60- to 80-km-thick present-day lithosphere beneath the study region,significantly thinned from the Paleozoic lithosphere of >180 *** lithosphere asthenosphere boundary(LAB) is coherently imaged along the 00-km east-west profile,displaying an arc-like shape with its apex roughly coincident with the transverse location of the Tanlu Fault Zone on the *** obvious uplift from6 km to2.km of the Moho is also clearly detected right below this fault *** coincidence of the imaged Moho uplift and the LAB apex with the surface location of the Tanlu Fault Zone provides seismological evidence for the steep geometry and deep penetration of the fault system,and indicates that the Tanlu Fault Zone might have acted as a major channel for anthenosphere upwelling during the Mesozoic-Cenozoic continental extension and lithospheric thinning in eastern *** analysis and synthetic modeling suggest that both the Moho and the LAB are sharp and *** latter,in particular,is constrained to have a 3-7%drop in S wave velocity over a depth range of 10 km or *** a rapid velocity change at the base of the lithosphere in the study region cannot be solely explained by thermal variation,but likely reflects the presence of volatiles or melt in the asthenosphere,or is partially attributed to the compositional contrast between the preserved depleted and dehydrated cratonic lithospheric veneer and the uplifted hydrated and fertile asthenospheric materials.

关键词： Tanlu Fault Zone Receiver function Migration Lithosphere thinning

Time-frequency analysis of the dispersive Rayleigh wave in stratified media

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Chinese Journal of Acoustics 2006年第4期25卷 297-309页

作者： LU Laiyu WANG Chenghao ZHANG Bixing institute of Acoustics Chinese Academy of Sciences Beijing 100080 institute of geophysics China Earthquake Administration Beijing 100085

The dispersive characteristic of the Rayleigh wave propagating in a stratified media was analyzed by a time-frequency analysis method, the Reassignment of Smooth Pseudo-Wigner Ville Distribution （RSPWVD）. Theoretical simulations and experiments were implemented for a homogeneous half-space and a two-layered half-space. It is indicated that the group velocity dispersion curves in different frequency ranges obtained by experimental result are all corresponding to the dominant modes in their surface displacement amplitudes. Such a mode-identification of the multi-mode Rayleigh waves is required in inversing the medium parameters.

关键词： frequency ranges analysis method Rayleigh waves group velocity

Planetary wave-type oscillations in the ionosphere and their relationship to mesospheric/lower thermospheric *** disturbances at Wuhan(30.61N,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(30.61N,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 30-50%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 *** 39.7 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

Evaluation of Uncertainty of Earthquake Parameters for the Purpose of Seismic Zoning of Iran

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Earthquake Research in China 1997年第2期11卷 78-93页

作者： Mirzaei Noorbakhsh,Gao Mengtan,and Chen Yuntaiinstitute of geophysics,SSB,{2. 100081,China institute of geophysics,Tehran University,Tehran 14394,Iran

An efficient procedure is used for explicit description and evaluation of uncertainty of earthquake parameters in the uniform catalog of earthquakes in Iran and neighboring *** inadequate number of local and regional seismographic stations,poor station distribution,and Inadequacy of velocity models have resulted in conspicuous uncertainty in different parameters of recorded *** a comprehensive seismic hazard analysis such uncertainties should be *** of magnitude and location of events are evaluated for three different time periods,namely,historical,early instrumental,and modern instrumental time periods,for which existing seismological information differ widely in quantity,quality,and *** is concluded that an uncertainty of 0.2.0.3 units of magnitude and 10-15 km in epicenter determinations should be considered in the most favorable *** of the hypocenters of earthquakes in Iran can be considered as reliable,unless supported by other information such as

关键词： Evaluation of Uncertainty of Earthquake Parameters for the Purpose of Seismic Zoning of Iran ISC

Receiver function migration image of the deep structure in the Bohai Bay Basin,eastern China

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Receiver function migration image of the deep structure in t...

中国科学院地质与地球物理研究所2.06学术年会

作者： Ling Chen~*,Tianyu Zheng,and Weiwei Xu seismological Laboratory(SKL-LE),institute of Geology and{2.,Chinese Academy of Sciences,beijing 10002.,PR China

We apply a receiver function poststack migration method to image the crustal and upper mantle structures beneath the Bohai Bay Basin,eastern *** thick sediments of the basin appear to have a substantial influence on the migrated image of the deep *** using the surface reflected PpPs multiples instead of the commonly used Ps converted phases,a curved Moho is coherently imaged,showing a thinned crust of 30 km in the basin area compared with the >40-km thick crust in the west mountain *** incorporating the sedimentary velocity model into migration,both the 410-km and the 660-km discontinuities present a simple structural feature with relatively flat topography within the basin’s interior,although possible local structural complexities may exist at the base of the upper mantle around the boundary areas of the *** mantle transition zone is on average 10-15 km thicker than the global average,reflecting a cold lower upper mantle environment that is distinct from the warm shallow upper mantle of the region.

关键词： Bohai Bay Basin Receiver function Migration Mantle transition zone Sediment influence

Distinct lateral variation of lithospheric thickness in the Northeastern North China Craton

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Distinct lateral variation of lithospheric thickness in the ...

中国科学院地质与地球物理研究所2.08学术年会

作者： Ling Chen~*,Wang Tao,Liang Zhao,Tianyu Zheng seismological Laboratory(SKL-LE),institute of Geology and{2.,Chinese Academy of Sciences,beijing 10002.,China

A detailed knowledge of the thickness of the lithosphere in the northeastern North China Craton(NCC) is important for understanding the significant tectonic reactivation of the craton in the Mesozoic and Cenozoic *** achieve this goal by applying the newly proposed wave equation-based migration technique to the S-receiver functions recently collected in the *** negative signals are identified below the Moho in all the S-receiver function-migrated images and stacks,which we interpret as representing the S-to-P conversions from the lithosphereasthenosphere boundary(LAB).The imaged LAB is as shallow as～60-70 km in the southeast basin and coastal areas and deepens to no more than 140 km in the northwest mountain ranges and continental *** observations indicate widespread lithospheric thinning in the study region in comparison with the>180-km lithospheric thicknesses typical of most cratonic *** revealed topography of the LAB generally agrees with the lateral variation in upper mantle seismic anisotropy previously measured through SKS splitting *** particular,a sharp LAB step of～40 km is detected at the triple junction of the basin and mountains,at almost the same place where an abrupt change from NW-SE to NE-SW in fast polarization direction of shear waves was *** findings suggest a close correlation between the seismic anisotropy and hence deformation of the upper mantle,the lithospheric thickness,and the surface tectonics of the northeastern *** the thinned lithosphere and the NW-SE fast shear wave polarizations in the east areas probably are related to the dominant NW-SE tectonic extension in the late Mesozoic-Cenozoic time,the thicker lithosphere and the NE-SW fast polarization direction in the west mountain ranges may reflect earlier contractional deformations of the *** tests indicate that the LAB beneath the northeastern NCC is a well-defined zone 10-2. km *** with seismic tomography

关键词： lithosphere-asthenosphere boundary northeastern North China Craton S-receiver functions lithospheric reactivation

Confidence Evaluation of Medium-and Long-Term Earthquake Prediction by Use of the Analytical Hierarchy Process

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Earthquake Research in China 1996年第2期10卷 69-79页

作者： Wang Xiaoqing and Gao MengtanCenter for Analysis and Prediction, SSB, beijing 100036, China institute of{2., SSB, beijing 100081, China

This paper offers an approach to the relative confidence level of medium- and long-term earthquake prediction methods by use of the analytical hierarchy process (AHP). We construct the criterion judgment matrices according to the results of an expert questionnaire known as the Delphi scheme. From the matrices we can obtain a scale for the relative preference or priority weight of each factor. The quantitative weights might be applied to make synthetic prediction of earthquake risk areas in the northern part of the North China seismic region.

关键词： Seismic analysis Confidence level Prediction version.