The dependence of response spectrum on the tectonic ambient shear stress field     

李保昆  陈培善  白彤霞 《地震学报(英文版)》2005,18(3):313-321

Introduction The acceleration response spectrum and peak ground acceleration are the necessary and im-portant parameters in earthquake-resistant design at present. They are still active research field. With the increase of digital high accurate strong motion observation data, especially the earth-quakes of Loma Prieta (M=7.0) in 1989; Landers (M=7.3) in 1992; Big Bear (M=6.4) in 1994 and Northridge (M=6.7) in 1994 in USA; Kozani (M=6.6) earthquake and afteshocks in 1995 in Greece; Dinar…  相似文献   

Study on comparison between absolute and relative input energy spectra and effects of ductility factor     

公茂盛  谢礼立 《地震学报(英文版)》2005,18(6):717-726

Introduction Estimation of an attenuation relationship for strong ground motion parameters has been an interesting research subject in the field of engineering seismology and has played a very important role in seismic safety evaluation, seismic zoning, seismic hazard evaluation of major constructions, etc. At present, the generally used parameters include peak acceleration, peak velocity and elastic response spectrum. Such parameters mentioned above are essentially independent of the duration…  相似文献   

Thermodynamic conditions of framework grain dissolution of clastic rocks and its application in Kela 2 gas field   总被引：2，自引：2，他引：2  

LAI Xingyun  YU Bingsong  CHEN Junyuan  CHEN Xiaolin  LIU Jianqing  MEI Mingxiang  JING Weiguang & CHENG Suhua School of Earth Sciences  Mineral Resources  China University of Geosciences  Beijing  China  Key Laboratory of Lithospheric Tectonics  Deep-level Process  Exploration of Ministry of Education  Beijing  China 《中国科学D辑(英文版)》2005,48(1):21-31

Feldspar and clastic debris are the most important constituent framework grains of sedimentary clastic rocks and their chemical dissolution plays an essential role in the formation and evolution of the secondary pore in the reservoir rocks. On the basis of thermodynamic phase equilibrium, this study investigates the chemical equilibrium relationships between fluid and various plagioclase and K-feldspar in diagenesis of the sediments, particularly, the impact of temperature and fluid compositions (pH, activity of K+, Na+, Ca2+ and so on) on precipitation and dissolution equilibria of feldspars. Feldspar is extremely easily dissolved in the acid pore water with a low salinity when temperature decreases. The dissolution of anorthite end-member of plagioclase is related to the Ca content of the mineral and the fluid, higher Ca either in the mineral or in the fluid, easier dissolution of the feldspar. Moreover, the dissolution of albite end-member of plagioclase is related to Na of both the mineral and fluid,  相似文献   

A precise monitoring of snow surface height in the region of Lambert Glacier basin-Amery Ice Shelf,East Antarctica   总被引：2，自引：0，他引：2  

I.Allison 《中国科学D辑(英文版)》2005,48(1):100-111

The net surface snow accumulation on the Antarctic ice sheet is determined by a combination of precipitation, sublimation and wind redistribution. We present a one-year record of hourly snow-height measurements at LGB69 (70°50'S, 77°04'E, 1850 m a.s.l.). east side of Lambert Glacier basin (LGB), and 4 year record at G3 (70°53'S, 69°52'E, 84 m a.s.l.), Amery Ice Shelf (AIS). The measurements were made with ultrasonic sensors mounted on automatic weather stations installed at two sites. The snow accumulation at LGB69 is approximately 70 cm. Throughout the winter, between April and September, there was little change in surface snow height (SSH) at the two sites. The negative SSH change is due to densification at LGB69, and is due to both ablation and densification at G3. The strongest accumulation at two sites occurred during the period between October and March (accounting for 101.6% at LGB69), with four episodic increasing events occurring during 2002 for LGB69, and eight events during 1999-2002 for G  相似文献   

Distribution of chlorophyll-a off the Changjiang River and its dynamic cause interpretation   总被引：1，自引：1，他引：1  

ZHU Jianrong State Key Laboratory of Estuarine  Coastal Research  East China Normal University  Shanghai  China 《中国科学D辑(英文版)》2005,48(7)

Red tide,also called harmful algal bloom interna-tionally,is a disaster abnormal phenomenon of oceanecology with an explosive breed or dense assemble ofone or several phytoplanktons in a specific ocean en-vironment condition,colors the seawater,influencesand harms ocean living things.The formation of redtide is controlled mainly by a complex interplay ofbiological,physical and chemical processes,but themost main cause influencing the occurrence of red tideis the seawater eutrophication,i.e.,the…  相似文献   

Cause of winter gravity wave spectrum saturation     

WU Yongfu & XU Jiyao Laboratory for Space Weather  Center for Space Science  Applied Research  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2005,48(10)

Gravity waves play a significant role in establishing the large-scale circulation and structure of the middle atmosphere. Through gravity wave saturation proc-esses, such motions are believed to cause turbulence, resulting in divergence of momentum flux and the diffusion of heat and constituents in the meso-sphere[1,2]. The mechanisms that contribute signifi-cantly to the gravity wave saturation are thought to be the dynamical and convective instabilities[3]. However, it is difficult to distin…  相似文献   

Geochemistry of ore-forming fluids and geological significance of the Kuoerzhenkuola gold field in Xinjiang, China     

SHEN Ping  SHEN Yuanchao  LIU Tiebing  LI Guangming & ZENG Qingdong Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2005,48(11)

The Kuoerzhenkuola gold field (including the Kuo- erzhenkuola and the Buerkesidai gold deposits), lo- cated 68 km east of Jimunai County in northern Xing- jiang, China, is an important component of the Sawuer gold belt which is the eastward extending part of the Zarma-Sawur gold-copper belt in Kazakhstan. Some studies are concerned with the geology of the gold ores[1―3], the associated volcanic rocks[4], radiogenic isotope[5―8], and the ore-forming environment[8]. Most researchers inferr…  相似文献   

Study on simulating strong ground motion by fractal stochastic method     

GUO Meng-qiu  WANG Bin  XU Zhao-yong 《地震学报(英文版)》2005,18(4):490-495

The time history of strong ground motion can be synthesized by empirical Green's function (EGF) method.Firstly a large seismic event is discretized into a series of subevents; secondly recordings of earthquakes with proper size and spatial distribution are chosen as time history (EGF) of those subevents; finally the EGFs are summated to get the time history of ground motion caused by the large event.  相似文献   

2-D crustal Poisson’s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region   总被引：1，自引：0，他引：1  

Liu Zhi  Zhang Xian-kang  Wang Fu-yun  Duan Yong-hong  Lai Xiao-ling 《地震学报(英文版)》2005,18(3):345-353

Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave along the profile L ₁ are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson’s ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method, and it is also very effective to determine Poisson’s ratio distribution of deep seismic sounding profile, especially useful for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson’s ratio body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson’s ratio is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature. There is a high Poisson’s ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot substance. The lower part with high Poisson’s ratio, which stretches downward to Moho, is possibly the extrusion way of hot substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination of 3D crustal structure and magnetotelluric survey in this region. Foundation item: Key Project from China Earthquake Administration and the Project (95-11-02-01) from Ministry of Science and Technology (2001DIA10003). Contribution No. RCEG200401, Geophysical Exploration Center, China Earthquake Administration.  相似文献   

Studies on wind environment around high buildings in urban areas     

LIU Huizhi  JIANG Yujun  LIANG Bin  ZHU Fengrong  ZHANG Boyin  SANG Jianguo 《中国科学D辑(英文版)》2005,48(Z2)

High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in Beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings.  相似文献