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971.
山西交城断裂为太原盆地西界的主控边界断裂,断裂带附近历史上曾发生过6级地震.野外调查发现,沿交城断裂发现多处地裂缝.在交城县城北侧的坡底村-田家山村西一带地裂缝断续出露,裂缝与基岩隆起区与盆地倾斜平原的分界线的距离大约为200 m.  相似文献   
972.
Introduction The Great North China, located at longitude 106E to 124E and latitude 31N to 42N, in-cludes three secondary active tectonic blocks, Ordos, Yanshan and North China plain (Figure 1). The geological tectonics of these three secondary blocks is much different from each other. As a stable block with high rigidity, the Ordos block is mostly surrounded by down-faulted basins with an inactive interior since Cenozoic, although the fault zones along its boundary are strongly active wi…  相似文献   
973.
Introduction The Xiuyan earthquake(MS=5.4)on Nov.29,1999,occurred between Hushan town and Pi-anling town at the southeast end of the aftershocks of Haicheng earthquake(MS=7.3).These two earthquakes′sequences are highly similar in the way that the foreshocks are very frequent,focal mechanisms of the main shocks are about the same and fault strikes are approximately in the same direction.It is important to study these earthquakes for further research on seismogenesis to fore-cast earthquake…  相似文献   
974.
Introduction The anisotropy of the Earth crust medium is a common phenomenon(Crampin,1984).More and more observation materials and study results have proved that on most of the Earth′s upper crust is spread fluid-filled cracks and microcracks,which are aligned according to the contempo-rary stress-field.Such distributions of aligned cracks show effectively anisotropy to seismic wave and the phenomenon is called extensive-dilatancy anisotropy(EDA)(Crampin et al,1984).At the same time,it is …  相似文献   
975.
Introduction Ready and Renkin (1971) were the first to make the research on anisotropy problems in magnetotellurics (MT). The progress in the research is not evident because it is more complex and difficult than isotropic problems. Now, the one-dimensional (1D) anisotropy problems in MT have been well solved, while for the two-dimensional (2D) cases, the numerical solutions have only been obtained for some particular conditions (Ready and Renkin, 1975). As to the three-dimensional (3D) ani…  相似文献   
976.
Introduction Data mining (SHAO and YU, 2003) is a new kind of technique developed with database and artificial intelligence in recent years, which processes the data in the database to abstract the im- plied and pre-unknown, but potentially useful information and knowledge from large amounts of incomplete, noisy, blurring and stochastic data. For data mining, data purging is an important link beforehand that includes eliminating noise, making up lost domain, and deleting ineffective data, as…  相似文献   
977.
In the construction of Qinghai-Tibet railway,to avoid diseases caused by frost heave and thaw col-lapse of frozen ground,besides the normal bridges over the rivers,a lot of dry bridge structures have been built to replace subgrade in the regions of high tem-perature and high ice content frozen soil.So,the problems on forming mechanism of bearing capacity of pile foundation in cold regions already become one of hot spot problems in frozen soil engineering.Freezing force and frost heave force ar…  相似文献   
978.
Succeeding to multiply collisions of different blocks in Late Paleozoic[1―5], complex intracontinental structural deformation occurred in the Tianshan area during Mesozoic-Cenozoic[6―16], which controlled coeval basin-range evolution and resulted in intensive modi- fication and adjustment of the Paleozoic oil-gas reser- voirs[17―19]. The Kuqa Depression is a secendary struc- tural unit of the Tarim basin, in which Mesozoic- Ce- nozoic deposits occur in thickness of 6000―7000 m. The Kuq…  相似文献   
979.
1954年山丹7 1/4级地震概述   总被引:2,自引:0,他引:2  
1954年山丹7 1/4级地震的极震区烈度达X度,造成50人死亡,329人受伤,受灾面积4800 km2,山丹县城破坏最重.本文回顾、总结了山丹地震五十年的研究积累,重点论述了该地震的基本参数、震源机制、地震序列、地震烈度、地震破裂带、历史地震、震害及其损失等.  相似文献   
980.
Based on analysis of the air pollution observational data at 8 observation sites in Beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution emission inventory and improves the forecast level of air quality. Also this work employed a way of combining point and area forecasting, i.e. taking the products of CMAQ for a center site to forecast air pollution for other sites in vicinity with the scheme of model products "reanalysis" and average over the "area".  相似文献   
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