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Summation and decomposition of principal stresses in the crust

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Acta Seismologica Sinica(English Edition) 2004年第1期17卷 114-118页

作者： SHI Yao-lin(石耀霖) computational geodynamics laboratory Graduate School of Chinese Academy of Sciences Beijing 100039 China

In the compilation of World Stress Map, 9％ of data comes from overcoring and hydraulic fracturing measurement, 23％ from borehole breaking off, 63％ from earthquake focal mechanism, and 5％ from young geological inve... 详细信息

关键词： stress tensor earthquake mechanism

Discussion on the dynamic mechanism of Great North China area based on the observed stress data

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Acta Seismologica Sinica(English Edition) 2005年第1期18卷 1-11,124页

作者：冯向东魏东平陈棋福 computational geodynamics laboratory Graduate School of Chinese Academy of Sciences Earthquake Administration of Hebei Province Shijiazhuang 050021 China Institute of Earthquake Science China Earthquake Administration

Based on the constrained data from the observed stress orientation and the observed stress regime, the tectonic stress fields of the Great North China area has been simulated by using the pseudo-3D finite element method. The results indicate that the stress fields in this area are basically controlled by the push forces coming from the Pacific Plate and from the Tibet Plateau, and the WNW-ward action from the Pacific Plate play a more important role in North China plain block. In addition to that, the stress field in this area is also partly formed by the extension action from the mantle upwelling in perpendicular at the basin margins.

关键词： Great North China area stress regime finite element method dynamic simulation

Timing and structural controls on skarn-type and vein-type mineralization at the Xitian tin-polymetallic deposit, Hunan Province, SE China

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Acta Geochimica 2018年第2期37卷 295-309页

作者： Miao He Quanlin Hou Qing Liu Jiheng Zhang Jinfeng Sun Shichong Wu Haofeng Zhu Key laboratory of computational geodynamics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences 416 Geological Team Bureau of Geology and Mineral Exploration and Development of Hunan Province

Xitian tin-polymetallic deposit, located in the eastern Hunan Province, SE China, hosts quartz vein and skarn in the contact zone between carbonate and two stages granites. Critical geodynamic questions for South China are whether different types of mineralization form in the same time and how the magmatism–tectonic system controls the ore-forming process. Based on the distribution of the orebodies, six cassiterite samples from different types of mineralization are collected for dating. In-situ LA-MCICP-MS U–Pb isotopic data yielded concordia low intercept ages between 154 and 157 Ma, indicating that different types of mineralization belong to the same magmatism–mineralization system. Coupled with the study of the kinematic indicators, it suggests that the structural control of the wall rocks constrain the types of mineralization. These results provide further evidence of a close temporal link between the structure and the tin-polymetallic mineralization in Xitian deposit. Considering the structure in the district, granite dome plays an important role in the ore-forming process. The age and structural signatures in Xitian deposit are the response to the subduction of Pacific Plate.

关键词：矿化作用湖南省类型结构控制静脉 SE 中国

Temporal variation of noise correlation function(NCF) in Beijing and surroundings:Its relation with climate events and implications

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Earthquake Science 2009年第1期22卷 75-81页

作者： Changsheng Jiang Zhongliang Wu Institute of Geophysics China Earthquake Administration Beijing 100081 China laboratory of computational geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China

Noise correlation function （NCF） was calculated using the data of the Beijing Capital-Area Telemetered Digital Seismograph Network from June 12 to September 12, 2005. Signal-to-noise ratio （SNR） is used to characterize the quality of NCF at each station pair. The SNR （in dB） is shown to be dependent on the separation distance R of the station pair via SNR= A -BlogR. ＇Normalized average SNR＇ for all the station pairs can then be calculated, as represented by the value of SNR taking R = 250 km in the empirical SNR-R relation, to measure the overall quality of the NCF result. The ＇normalized average SNR＇ of the NCF shows temporal variation and is apparently dependent on the root-mean-square （RMS） velocity of the microseism. The result obtained by this experiment provides clues to the explanation of the properties of NCF, such as the dominant mechanism underlying （diffuse wave fields or uncorrelated sources）, and the dependence of SNR on the time length of recordings.

关键词： noise correlation function Beijing and surroundings signal-to-noise ratio

Polarimetric entropy of the ocean surface with a two-scale scattering model

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Acta Oceanologica Sinica 2014年第1期33卷 102-108页

作者： WANG Wenguang LI Haiyan SONG Xingai School of Electronic and Information Engineering Beihang University Key laboratory of computational geodynamics Chinese Academy of Sciences University of the Chinese Academy of Sciences National Satellite Ocean Application Service State Oceanic Administration

The relationships among an ocean wave spectrum,a fully polarimetric coherence matrix,and radar parameters are deduced with an electromagnetic wave ***,the relationship between the polarimetric entropy and ocean wave spectrum is established based on the definition of entropy and a twoscale scattering model of the ocean *** is the first time that the polarimetric entropy of the ocean surface is presented in ***,the relationships among the fully polarimetric entropy and the parameters related to radar and ocean are *** study is the basis of further monitoring targets on the ocean surface and deriving oceanic information with the entropy from the ocean *** contrast enhancement between human-made targets and the ocean surface with the entropy is presented with quad-pol airborne synthetic aperture radar（AIRSAR） data.

关键词： entropy ocean wave spectrum polarimetric synthetic aperture radar Polsar two-scale scattering mode contrast enhancement

Locating seismic scatterers at the base of the mantle beneath eastern Tibet with PKIKP precursors

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Chinese Science Bulletin 2010年第24期55卷 723-729页

作者： SHEN XuZhang 1,2,3 & ZHOU HuiLan 1 1 laboratory of computational geodynamics,Graduate University of the Chinese Academy of Sciences,Beijing 100049,China 2 Lanzhou Institute of Seismology,China Earthquake Administration,Lanzhou 730000,China 3 Lanzhou Base of Institute of Earthquake Prediction,China Earthquake Administration,Lanzhou 730000,China laboratory of computational geodynamics Graduate University of the Chinese Academy of Sciences Beijing China Lanzhou Institute of Seismology China Earthquake Administration Lanzhou China Lanzhou Base of Institute of Earthquake Prediction China Earthquake Administration Lanzhou China

Clear PKIKP precursors were observed from the Lanzhou CTBTO seismic *** measured their incident angles,arriving azimuths and differential travel times with respect to the PKIKP arrivals using array analysis *** measurements allowed us to locate the scatterers that generated the observed *** found that the scatterers are located in the lowermost mantle beneath eastern Tibet,which is featured by a high-velocity anomaly based on previous tomographic *** high velocity anomaly was interpreted as the slab remnants of the ancient Tethys *** thus speculate that the observed scatterers are either related or induced by the subducted slab.

关键词：地震前兆西藏东部下地幔散射定位地震台阵入射角度旅行时间

Ocean surface wave measurements from fully polarimetric SAR imagery

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Science China Earth Sciences 2015年第10期58卷 1849-1861页

作者： XIE Tao William PERRIE HE YiJun LI HaiYan FANG He ZHAO ShangZhuo YU WenJin School of Marine Sciences Nanjing University of Information Science and Technology Fisheries and Oceans Canada Bedford Institute of Oceanography Key laboratory of computational geodynamics Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences

A new method for the retrieval of ocean wave parameters from SAR imagery is developed,based on the shape-from-shading(SFS)***,the SFS technique has been used in the reconstruction of 3D landform information from SAR images,in order to generate elevation maps of topography for land ***,in order to retrieve ocean wave characteristics,we apply the SFS methodology,together with a method to orient the angular measurements of the azimuth slope and range slope,in the measurement of ocean surface *** method is applied to high resolution fine-quad polarization mode(HH,VV,VH and HV)C-band RADARSAT-2 SAR imagery,in order to retrieve ocean wave spectra and extract wave *** in situ buoy measurements are used to validate the reliability of this *** show that the method can reliably estimate wave height,dominant wave period,dominant wave length and dominant wave direction from C-band SAR *** advantage of this method is that it does not depend on modulation transfer functions(MTFs),in order to measure ocean surface *** method can be used in monitoring ocean surface wave propagation through open water areas into ice-covered areas,especially the marginal ice zone(MIZ)in polar oceans.

关键词：海洋波浪合成孔径雷达图像角测量表面波全极化 SAR图像从明暗恢复形状调制传递函数

Oil spill detection on the ocean surface using hybrid polarimetric SAR imagery

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Science China Earth Sciences 2016年第2期59卷 249-257页

作者： LI HaiYan PERRIE William ZHOU YuanZe HE YiJun Key laboratory of computational geodynamics Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Fisheries and Oceans Canada Bedford Institute of Oceanography School of Marine Sciences Nanjing University of Information Science and Technology

Hybrid-polarimetric SAR(synthetic aperture radar) is a new SAR mode, with relatively simple architecture, low cost, and wide swath, which will be carried by several Earth-observing systems from now to the near future. Here, we show how the second Stokes parameter of hybrid-polarimetric SAR can be employed to detect oil on the ocean surface using the classic well-known Otsu threshold methodology, in relation to contributions from different polarizations and dampening effects on backscatter intensity, neglecting the specific scattering mechanisms and oil types for an oil-covered surface. The detection methodology is demonstrated to be reliable in three example cases: oil-on-water experiments conducted by the Norwegian Clean Seas Association, natural oil seeps from the Gulf of Mexico, and observations from the Deep Water Horizon oil spill disaster in 2010.

关键词：合成孔径雷达图像极化SAR 检测海面溢油混合地球观测系统海洋表面后向散射强度

Treatment of discontinuities inside Earth models:Effects on computed coseismic deformations

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Earth and Planetary Physics 2021年第1期5卷 90-104页

作者： Jie Dong Gabriele Cambiotti HanJiang Wen Roberto Sabadini WenKe Sun Chinese Academy of Surveying and Mapping Beijing 100036China Department of Earth Sciences University of MilanMilano 20133Italy Key laboratory of computational geodynamics University of Chinese Academy of SciencesBeijing 100049China

In this paper,we study how coseismic deformations calculated in 1066 Earth models are affected by how the models treat Earth *** the results of applying models 1066A(continuous)and 1066B(discontinuous),we find that the difference in Love numbers of strike-slip and horizontal tensile sources are bigger than dip-slip and vertical tensile *** collectively,discontinuities have major effects on Green’s functions of four independent *** the near-field coseismic deformations of the 2013 Okhotsk earthquake(Mw 8.3),the overall differences between theoretical calculations in vertical displacement,geoid,and gravity changes caused by discontinuities are 10.52 percent,9.07 percent and 6.19 percent,with RMS errors of 0.624 mm,0.029 mm,and 0.063μGal,*** difference in far-field displacements is small,compared with GPS data,and we can neglect this *** the shallow earthquake,2011 Tohoku-Oki earthquake(Mw 9.0),the differences in near-field displacements are 0.030 m(N-S),0.093 m(E-W),and 0.025 m(up-down)in our study area with the ARIA slip model,which gives results closer to GPS data than those from the USGS *** difference in vertical displacements and gravity changes on the Earth’s surface caused by discontinuities are larger than 10 *** difference in the theoretical gravity changes at spatially fixed points truncated to degrees 60,as required by GRACE data,is 0.0016μGal and the discrepancy is 11 percent,with the theoretical spatial gravity changes from 1066B closer to observations than from *** results show that an Earth model with discontinuities in the medium has a large effect on the calculated coseismic deformations.

关键词： discontinuities Earth model coseismic deformations GPS GRACE