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Condition Assessment of August A. Busch Bridge Deck Using Portable Seismic Property Analyzer and Ground Penetrating Radar 被引量:1
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作者 Samie Hamad Wajdi Ammar +1 位作者 Salah Shaniba Abdelmajeed Altlomate 《Open Journal of Civil Engineering》 2022年第1期14-21,共8页
Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSP... Ground penetrating radar (GPR) and the portable seismic property analyzer (PSPA) have been extensively used in the past two decades for monitoring, quantifying, and mapping the deterioration of bridge decks. Using PSPA and GPR ensures regular monitoring of bridge conditions, leads to the early detection of deterioration. This research is to address the condition of August A. Busch bridge deck owned by the Missouri Department of Conservation. Visual inspection, GPR, and PSPA data were acquired on the bridge deck. Over 90% of the bridge deck was in fair to good condition with an average compressive strength of over 2500 psi. GPR data showed no indication of significant deterioration. The overall bridge deck was determined to be in fair to good condition. 展开更多
关键词 Ground Penetrating Radar Portable seismic property Analyzer Bridge Deck Concrete Deterioration
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Simulation by Dislocation Model and Anomaly Property Determination of Huge Leveling Deformation at Linfen Seismic Station 被引量:1
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作者 Liu Ruichun Jin Hongliang 《Earthquake Research in China》 CSCD 2016年第1期100-107,共8页
In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation fiel... In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation field distribution based on the rectangular fault dislocation model and measured the ground deformation field of the study area using D-InS AR technology. The results are as follows:( 1) Theoretically,the ground vertical deformation field caused by fault movement could be within the elliptical deformation area with the long axis parallel to the fault strike. The largest deformation region is located in the center of the area in the hanging wall of the fault,and the deformation gradually decreases to zero toward the periphery; the impact range induced by the two deformations is respectively as follows: The long axes are about 18 km and26km,the short axes are about 12 km and 17 km and the obvious deformation amplitude is about 1- 3mm and 4- 14 mm.( 2) The measured deformation field by D-InS AR shows that there is no continuous deformation area consistent with the fault strike,and only the presence of land subsidence possibly caused by groundwater excessive exploitation,with the deformation amplitude about 10- 12 mm and 1- 5mm.( 3) The measured deformation field is not consistent with the theoretical result on deformation area and amplitude,which indicates that the fault movement is not the main cause of Linfen huge leveling deformation,but may rather be because of local deformation of the soil layers in the hanging wall of the fault.( 4) By combining the fault dislocation model simulation with the D-InS AR technology measurement,we can determine effectively the nature of the anomalyof the huge cross-fault leveling deformation,thus provide scientific basis for verification of significant leveling anomalies. 展开更多
关键词 The leveling at Linfen seismic station Huge deformation Fault dislocationmodel D-InSAR Anomaly property determination
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Elastic and Seismic Properties of Dabie-Sulu Ultrahigh Pressure Metamorphic Rocks 被引量:1
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作者 WANG Qian JI Shaocheng +2 位作者 SUN Shengsi Matthew H.SALISBURY Hartmut KERN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第1期20-37,共18页
Lame modulus (λ) and shear modulus (μ) are among the most important, intrinsic, elastic constants of rocks. Using 7. and μ could be much more advantageous than using P- and S-wave velocities (Vp and Vs). Here... Lame modulus (λ) and shear modulus (μ) are among the most important, intrinsic, elastic constants of rocks. Using 7. and μ could be much more advantageous than using P- and S-wave velocities (Vp and Vs). Here we quantified these equivalent isotropic elastic moduli for 115 representative rocks from the ultrahigh pressure (UHP) metamorphic terrane of the Dabie-Sulu orogenic belt (China) and their variations with pressure (P), temperature (T), density (p), Vp, Vs and mineralogical composition. Both moduli increase nonlinearly and linearly with increasing pressure at low (〈200-300 MPa) and high (〉200-300 MPa) pressures, respectively. In the regime of high pressures, 7. and IX decrease quasi-linearly with increasing temperature with temperature derivatives dλ/dT and dμ/dT generally in the range of -10×10-3 to -1×10-3 GPa/℃. Dehydration of water-bearing minerals such as serpentine in peridotites and chlorite in retrograde eciogites results in an abrupt drop in 7. while μ remains almost unchanged. In Z-p, μ-p and 7.-IX plots, the main categories of UHP rocks can be characterized. Serpentinization leads to significant decreases in μ and 7. as serpentine has extremely low values of Z, μ and p. Eclogites, common mafic rocks (mafic gneiss, metagabbro and amphibolite), and felsic rocks (orthogneiss and paragneiss) have high, moderate and low μ and λ values, respectively. For pyroxenes and olivines, λ increases but μ decreases with increasing Fe/Mg ratios. For plagioclase feldspars, both Z and μ exhibit a significant positive correlation with anorthite content. SiO2-rich felsic rocks and quartzites are deviated remarkably from the general trend lines of the acid-intermediate-mafic rocks in Vs-p, μ-p, λ-Vp,λ-Vs and μ-λ diagrams because quartz has extremely low λ (-8.1 GPa) and p (2.65 g/cm3) but moderate μ (44.4 GPa) values. Increasing the contents of garnet, rutile, ilmenite and magnetite results in a significant increase in the λ and μ values of the UHP metamorphic rocks. However, either λ or μ is insensitive to the compositional variations for pyralspite (pyrope-almandine-spessartine) solution series. The results provide potentially improved constraints on characterization of crustal composition based on the elastic properties of rocks and in situ seismic data from deep continental roots. 展开更多
关键词 seismic properties elastic constants ultrahigh pressure metamorphic rocks Dabie-Sulu deep continental roots
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Fabrics and Seismic Properties of Ophiolites: Implications for Mantle Flow
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作者 WANG Qin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期244-,共1页
Based on ophiolite sequences,seismic velocities of rocks and seismic profiles of ocean basins,the oceanic crust-mantle boundary can be defined as the contact between the solid,ductile deformed mantle and the
关键词 Fabrics and seismic Properties of Ophiolites Implications for Mantle Flow
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Microstructures, Fabrics, and Seismic Properties of Mylonitic Amphibolites: Implications for Strain Localization in a Thickening Anisotropic Middle Crust of the North China Craton
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作者 Siqi Liu Bo Zhang +5 位作者 Jinjiang Zhang Jian Zhang Lei Guo Tao Wang Baoyou Hang Xiaorong Li 《Journal of Earth Science》 SCIE CAS CSCD 2024年第3期769-785,共17页
Strain localization processes in the continental crust generate faults and ductile shear zones over a broad range of scales affecting the long-term lithosphere deformation and the mechanical response of faults during ... Strain localization processes in the continental crust generate faults and ductile shear zones over a broad range of scales affecting the long-term lithosphere deformation and the mechanical response of faults during the seismic cycle.Seismic anisotropy originated within the continental crust can be applied to deduce the kinematics and structures within orogens and is widely attributed to regionally aligned minerals,e.g.,hornblende.However,naturally deformed rocks commonly show various structural layers(e.g.,strain localization layers).It is necessary to reveal how both varying amphibole contents and fabrics in the structural layers of strain localization impact seismic property and its interpretations in terms of deformation.We present microstructures,petrofabrics,and calculate seismic properties of deformed amphibolite with the microstructures ranging from mylonite to ultramylonite.The transition from mylonite to ultramylonite is accompanied by a slight decrease of amphibole grain size,a disintegration of amphibole and plagioclase aggregates,and amphibole aspect ratio increase(from 1.68 to 2.23),concomitant with the precipitation of feldspar and/or quartz between amphibole grains.The intensities of amphibole crystallographic preferred orientations(CPOs)show a progressively increasing trend from mylonitic layers to homogeneous ultramylonitic layers,as indicated by the JAm index increasing from 1.9–4.0 for the mylonitic layers and 4.0–4.8 for the transition layer,to 5.1–6.9 for the ultramylonitic layers.The CPO patterns are nearly random for plagioclase and quartz.Polycrystalline amphibole aggregates in the amphibolitic mylonite deform by diffusion,mechanical rotation,and weak dislocation creep,and develop CPOs collectively.The polymineralic matrix(such as quartz and plagioclase)of the mylonite and the ultramylonite deform dominantly by dissolution-precipitation,combined with weak dislocation creep.The mean P and S wave velocities are estimated to be 6.3 and 3.5 km/s,respectively,for three layers of the mylonitic amphibolite.The respective maximum P and S anisotropies are 1.5%–6.4%and 1.8%–4.5%for the mylonite layers of the mylonitic amphibolite,and 6.0%–6.9%and 4.5%–5.0%for the transition layers;but for the ultramylonite layers,these values increase significantly to 8.0%–9.1%and 5.1%–6.0%,respectively.Furthermore,increasing strain(strain localization)generates significant variations in the geometry of the seismic anisotropy.This effect,coupled with the geographical orientations of structures in the Hengshan-Wutai-Fuping complex terrains,can generate substantial variations in the orientation and magnitude of seismic anisotropy for the continental crust as measured by the existing North China Geoscience Transect.Thickened amphibolitic layers by extensively folding or thrusting in the middle crust can explain the strong shear wave splitting and the tectonic boundary parallel fast shear wave polarization beneath the Hengshan-Wutai-Fuping complex terrains.Therefore,signals of seismic anisotropy varying with depth in the deforming continent crust need not deduce depth-varying kinematics or/and tectonic decoupling. 展开更多
关键词 amphibolitic mylonite MICROSTRUCTURES petrofabrics seismic property middle crust rheology tectonics.
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On the Disadvantages of the NEHRP Soil Classification
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作者 Alexander Stepanovich Aleshin 《Open Journal of Earthquake Research》 2021年第1期1-15,共15页
The study of the relationship of local ground conditions with the parameters </span><span style="font-family:Verdana;">of seismic vibrations carried out by the section of engineering seismology&l... The study of the relationship of local ground conditions with the parameters </span><span style="font-family:Verdana;">of seismic vibrations carried out by the section of engineering seismology</span><span style="font-family:Verdana;"> called seismic microzonation. In</span><i> </i><span style="font-family:Verdana;">this branch of applied science radical changes have taken place at the end of the last century. The Commission on Seismic Safety of the National Institute of Building Sciences of the United States has developed new recommendations, which are significantly different from all that used in the world practice of anti-seismic construction. The main provisions of this NEHRP (National Earthquake Hazards Reduction Program) classifica</span><span style="font-family:Verdana;">tion adopted in many national building codes, including Eurocode 8. At the same time, a number of papers appeared in subsequent years criticizing the </span><span style="font-family:Verdana;">use of the NEHRP soil classification. This article examines in detail and, </span><span style="font-family:Verdana;">most</span><span style="font-family:Verdana;"> importantly, comprehensively the shortcomings of the NEHRP classification. 展开更多
关键词 seismic Site Properties Classification Site Class
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Effects of Lattice Preferred Orientation and Retrogression on Seismic Properties of Eclogite
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作者 史锋 王永锋 +1 位作者 徐海军 章军锋 《Journal of Earth Science》 SCIE CAS CSCD 2010年第5期569-580,共12页
We report here lattice preferred orientations (LPOs) and seismic properties of eclogites from the Sulu (苏鲁) UHP terrane. Our results show strong fabrics in omphacite and amphibole, and approximately random fabri... We report here lattice preferred orientations (LPOs) and seismic properties of eclogites from the Sulu (苏鲁) UHP terrane. Our results show strong fabrics in omphacite and amphibole, and approximately random fabrics in garnet with or without strong shape preferred orientations (SPOs). Dislocation creep is likely to be responsible for the observed omphacite fabrics that vary with geometry and orientation of finite strain ellipsoid. Weak garnet LPOs suggest that garnet did not accommodate plastic strain or was not deformed by dislocation creep with a dominant slip system. The calculated seismic properties of eclogites and their component minerals show a strong correlation with their LPOs. Seismic anisotropies are mostly induced by omphacite component in fresh eclogites and by amphibole component in retrograded eclogites, respectively. Retrogression of omphaeite to amphibole and quartz will increase seismic anisotropies but decreases seismic velocities of eclogite. Garnet component increases the seismic velocities but decreases seismic anisotropies of eciogite. Comparison of the calculated and the measured seismic properties of eclogites suggests that both methods resolve comparable results with some discrepancies. Compositional layering can play a very important role in determining the seismic properties of eclogites in addition to LPO. 展开更多
关键词 ECLOGITE LPO RETROGRESSION seismic property deformation mechanism.
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Properties of three seismic events in September 2017 in the northern Korean Peninsula from moment tensor inversion 被引量:6
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作者 Libo Han Zhongliang Wu +1 位作者 Changsheng Jiang Jie Liu 《Science Bulletin》 SCIE EI CAS CSCD 2017年第23期1569-1571,共3页
In September 2017 three noticeable seismic events occurred in the northern Korean Peninsula (Fig. 1; Table 1). Democratic People's Republic of Korea (DPRK) authorities announced that the first M6.3 event on Septe... In September 2017 three noticeable seismic events occurred in the northern Korean Peninsula (Fig. 1; Table 1). Democratic People's Republic of Korea (DPRK) authorities announced that the first M6.3 event on September 3rd was a "successfully conducted hydrogen-bomb test". The M4.6 event, some 8 min followed, was regarded as an implosion. 展开更多
关键词 Properties of three seismic moment tensor inversion
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Rock physical characteristics of deep dolomite under complex geological conditions:A case study of 4th Member of Sinian Dengying Formation in the Sichuan Basin,China
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作者 Chuang Li Shu-Xin Pan +4 位作者 Hong-Bin Wang Ji-Xin Deng Jian-Guo Zhao Zhi Li Yu Zhang 《Petroleum Science》 SCIE EI CAS 2024年第4期2370-2382,共13页
The deep-ultra deep carbonate reservoir in China,commonly subjected to modification of multi-stage diagenesis,has extremely high heterogeneity.Conventional rock physics analysis cannot accurately identify the elastic ... The deep-ultra deep carbonate reservoir in China,commonly subjected to modification of multi-stage diagenesis,has extremely high heterogeneity.Conventional rock physics analysis cannot accurately identify the elastic responses of reservoir.Here,the rock physics properties of the dolomite from the 4th Member of the Sinian Dengying Formation are experimentally measured,and the change law of rock physics characteristics is investigated within the framework of the diagenetic processes by the analysis of the elastic and petrologic characteristics,pore structure,and sedimentary environments.The results show that the differentiated diagenesis results in different pore structure characteristics and microtexture characteristics of the rock.The microbial dolomite of the algal mound-grain beach facies is subjected to the contemporaneous microbial dolomitization and seepage-reflux dolomitization,penecontemporaneous selective dissolution,burial dolomitization,and hydrothermal dolomitization.The resultant crystalline dolomite is found with one main type of the dolomite crystal contact boundaries,and the dissolution pore is extensive development.The siliceous,muddy,and limy dolomite of the interbeach sea environment mainly experiences the weak capillary concentration dolomitization,intensive mechanical compaction-induced densification,and burial dolomitization.Such crystalline dolomite is observed with four types of contact boundaries,namely the dolomite contact,clay contact,quartz contact,and calcite contact boundaries,and porosity mostly attributed to residual primary inter-granular or crystalline pores.The samples with the same crystal boundary condition have consistent correlations between the compressional-and shear-wave velocities,and between the compressional-wave velocity and the velocity ratio.Additionally,the variation of the acoustic velocity with effective pressure and the intensity of pore-scale fluid-related dispersion are controlled by the differentiation of pore structure types of the samples.The varied effects of soft pores like micro-cracks on the compressional-and shearwave velocity causes considerable changes in the relationships between the compressional-and shearwave velocities,compressional-wave velocity and velocity ratio,and porosity and acoustic velocity.This research is an attempt to demonstrate a novel method for investigating the rock physics variation of rock during the geological process,and the obtained findings can provide the rock physics basis for seismic prediction of the characteristics of deep carbonate reservoirs. 展开更多
关键词 Deep-ultra deep carbonate reservoirs Rock physics properties Dolomite seismic elastic properties Micro-crack Pore structure types
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