强震动观测的应用   总被引：6，自引：0，他引：6  

李山有 《东北地震研究》2004,20(4):64-74

详细阐述了强震动观测的目的、意义和应用范围；分析了强震动观测与通常地震观测的区别；介绍了强震动观测的现状及发展前景。  相似文献   

地震动的空间变异性对多支承结构的影响   总被引：5，自引：0，他引：5  

王航  杨庆山 《世界地震工程》2004,20(1):54-69

导致地震动空间变异性的原因主要在于：几何不相关性效应、行波效应、局部场地条件效应。利用时程分析的方法分析了单跨框架结构和美国Las Vegas市区内某24跨立交桥的简化模型，对地震动空间变异性三个主要因素的单独影响、综合影响分别进行了系统分析。结果表明地震动的空间变异性改变了一致激励下结构的动力反应，并且引入了一致激励情况所不存在的拟静力反应，对结构的总反应具有很大的影响。与较激励的情况相比，结构的反应可能增大，也可能减小，这依赖于结构上截面位置、场地条件和所采用的地震动时程样本。  相似文献   

Geodetic Measurements of Crustal Deformation in the Western Mediterranean and Europe   总被引：15，自引：0，他引：15  

J.-M. Nocquet  E. Calais 《Pure and Applied Geophysics》2004,161(3):661-681

—Geodetic measurements of crustal deformation over large areas deforming at slow rates (<5 mm/yr over more than 1000 km), such as the Western Mediterranean and Western Europe, are still a challenge because (1) these rates are close to the current resolution of the geodetic techniques, (2) inaccuracies in the reference frame implementation may be on the same order as the tectonic velocities. We present a new velocity field for Western Europe and the Western Mediterranean derived from a rigorous combination of (1) a selection of sites from the ITRF2000 solution, (2) a subset of sites from the European Permanent GPS Network solution, (3) a solution of the French national geodetic permanent GPS network (RGP), and (4) a solution of a permanent GPS network in the western Alps (REGAL). The resulting velocity field describes horizontal crustal motion at 64 sites in Western Europe with an accuracy on the order of 1 mm/yr or better. Its analysis shows that Central Europe behaves rigidly at a 0.4 mm/yr level and can therefore be used to define a stable Europe reference frame. In that reference frame, we find that most of Europe, including areas west of the Rhine graben, the Iberian peninsula, the Ligurian basin and the Corsica-Sardinian block behaves rigidly at a 0.5 mm/yr level. In a second step, we map recently published geodetic results in the reference frame previously defined. Geodetic data confirm a counterclockwise rotation of the Adriatic microplate with respect to stable Europe, that appears to control the strain pattern along its boundaries. Active deformation in the Alps, Apennines, and Dinarides is probably driven by the independent motion of the Adriatic plate rather than by the Africa-Eurasia convergence. The analysis of a global GPS solution and recently published new estimates for the African plate kinematics indicate that the Africa-Eurasia plate motion may be significantly different from the NUVEL1A values. In particular, geodetic solutions show that the convergence rate between Africa and stable Europe may be 30–60% slower than the NUVEL1A prediction and rotated 10–30° counterclockwise in the Mediterranean.  相似文献   

一次沙尘暴过程锋生函数和地表热通量的数值诊断   总被引：7，自引：12，他引：7  

孙军  姚秀萍 《高原气象》2002,21(5):488-494

沙尘暴是我国西北地区春季常发生的一种灾害性天气现象。本文利用国家气象中心改进的PSU／NCAR的非静力中尺度模式MM5，对1995年5月16日我国西北地区发生的一次沙尘暴天气个例进行了锋生函数和地表热通量的诊断分析。结果表明，沙尘暴过程是冷锋在移至我国西北地区时产生的一种强烈锋生过程；地表感热通量明显大于地表潜热通量；有无地面热通量对比试验表明，热力因子在沙尘暴产生过程中具有重要作用。  相似文献   

Critical evaluation of strong motion in Kocaeli and Düzce (Turkey) earthquakes     

Eser Durukal   《Soil Dynamics and Earthquake Engineering》2002,22(7)

Turkey was struck by two major events on August 17th and November 12th, 1999. Named Kocaeli (M_w=7.4) and Düzce (M_w=7.2) earthquakes, respectively, the two earthquakes provided the most extensive strong ground motion data set ever recorded in Turkey. The strong motion stations operated by the General Directorate of Disaster Affairs, the Kandilli Observatory and Earthquake Research Institute of Bogazici University and Istanbul Technical University have produced at least 27 strong motion records for the Kocaeli earthquake within 200 km of the fault. Kocaeli earthquake has generated six motions within 20 km of the fault adding significantly to the near-field database of ground motions for M_w>=7.0 strike–slip earthquakes. The paper discusses available strong motion data, studies their attenuation characteristics, analyses time domain, as well as spectral properties such as spectral accelerations with special emphasis on fault normal and fault parallel components and the elastic attenuation parameter, kappa. A simulation of the Kocaeli earthquake using code FINSIM is also presented.  相似文献   

2001年昆仑山8.1级大震及其趋势研究   总被引：5，自引：0，他引：5  

门可佩 《地震》2002,22(3):39-44

通过对1996－2001年我国西部强震活动在时空上的有序特征及其与台湾强震之间关联性的研究，分析讨论了2001年昆仑山8．1级大震的重要意义。同时根据有序性分析对青藏块体北部地区未来7级强震趋势进行了预测。  相似文献   

Sealing law of far-field spectra based on observed parameters of the specific barrier model     

Apostolos S. Papageorgiou  Keiiti Aki 《Pure and Applied Geophysics》1985,123(3):353-374

A set of acceleration source spectra is constructed using the observed parameters of the specific barrier model of Papageorgiou and Aki. The spectra show a significant departure from the ²-model at the high frequency range. Specifically, the high frequency spectral amplitudes of seismic excitation are higher as compared to the level predicted by the ²-model. This is also supported by other observational evidence. The high frequency amplitudes of acceleration scale proportionally to the square root of the rupture areaS, to the rupture spreading velocityv, and to the local strain drop (/) (=strain drop in between barriers). The local strain drop in between barriers is not related in a simple way to the global strain drop, which is the strain drop estimated by assuming that it is uniform over the entire rupture area. Consequently, the similarity law does not apply. Using the source spectra which we constructed, we derive expressions for high frequency amplitudes of acceleration such asa _rms anda _max. Close to the fault both are independent of fault dimensions and scale as (/µ)(f)^1/2, while away from the fault plane they scale asW ^1/2(/µ)(f)^1/2, whereW is the width of the fault and f is the effective bandwidth of the spectra.  相似文献   

中国大陆共轭破裂强震     

冯希杰  苏刚 《内陆地震》1993,7(3):225-233

依据地震破裂、地震形变带、前震和余震分布,对中国大陆共轭破裂强震进行了初步研究。结果表明,强震共轭破裂现象较普遍,据资料至少有12个单强震、7个双主震和2个主震——强余震为共轭破裂强震。其共轭破裂特征在地震形变带展布、烈度等震线形态、前震和余震分布等方面表现明显。另外,共轭破裂强震具有共轭破裂面方位之一多为北北西向、双主震之间和主——强余震之间相隔时间为“7”和“9”的节律这2个主要的共同点。  相似文献   

Multibeam bathymetry and sidescan imaging of the Rivera Transform–Moctezuma Spreading Segment junction, northern East Pacific Rise: New constraints on Rivera–Pacific relative plate motion     

William L. Bandy  Franois Michaud  Jrme Dyment  Carlos A. Mortera-Gutirrez  Jacques Bourgois  Thierry Calmus  Marc Sosson  Jose Ortega-Ramirez  Jean-Yves Royer  Bernard Pontoise  Bertrand Sichler 《Tectonophysics》2008,454(1-4):70-85

To better understand the recent motion of the Pacific plate relative to the Rivera plate and to better define the limitations of the existing Rivera–Pacific plate motion models for accurately predicting this motion, total-field magnetic data, multibeam bathymetric data and sidescan sonar images were collected during the BART and FAMEX campaigns of the N/O L'Atalante conducted in April and May 2002 in the area surrounding the Moctezuma Spreading Segment of the East Pacific Rise, located offshore of Manzanillo, Mexico, at 106°16′W, between 17.8°N and 18.5°N. Among the main results are: (1) the principle transform displacement zone of the Rivera Transform is narrow and well defined east of 107o15′W and these azimuths should be used preferentially when deriving new plate motion models, and (2) spreading rates along the Moctezuma Spreading Segment should not be used in plate motion studies as either seafloor spreading has been accommodated at more than one location since the initiation of seafloor spreading in the area of the Moctezuma Spreading Segment, or this spreading center is not a Rivera–Pacific plate boundary as has been previously assumed. Comparison of observed transform azimuths with those predicted by the best-fit poles of six previous models of Rivera–Pacific relative motion indicate that, in the study area, a significant systematic bias is present in the predictions of Rivera–Pacific motion. Although the exact source of this bias remains unclear, this bias indicates the need to derive a new Rivera–Pacific relative plate motion model.  相似文献   

Apparent/spurious multifractality of data sampled from fractional Brownian/Lévy motions     

Shlomo P. Neuman 《水文研究》2010,24(15):2056-2067

Many earth and environmental variables appear to be self‐affine (monofractal) or multifractal with spatial (or temporal) increments having exceedance probability tails that decay as powers of − α where 1 < α ≤ 2. The literature considers self‐affine and multifractal modes of scaling to be fundamentally different, the first arising from additive and the second from multiplicative random fields or processes. We demonstrate theoretically that data having finite support, sampled across a finite domain from one or several realizations of an additive Gaussian field constituting fractional Brownian motion (fBm) characterized by α = 2, give rise to positive square (or absolute) increments which behave as if the field was multifractal when in fact it is monofractal. Sampling such data from additive fractional Lévy motions (fLm) with 1 < α < 2 causes them to exhibit spurious multifractality. Deviations from apparent multifractal behaviour at small and large lags are due to nonzero data support and finite domain size, unrelated to noise or undersampling (the causes cited for such deviations in the literature). Our analysis is based on a formal decomposition of anisotropic fLm (fBm when α = 2) into a continuous hierarchy of statistically independent and homogeneous random fields, or modes, which captures the above behaviour in terms of only E + 3 parameters where E is Euclidean dimension. Although the decomposition is consistent with a hydrologic rationale proposed by Neuman (2003), its mathematical validity is independent of such a rationale. Our results suggest that it may be worth checking how closely would variables considered in the literature to be multifractal (e.g. experimental and simulated turbulent velocities, some simulated porous flow velocities, landscape elevations, rain intensities, river network area and width functions, river flow series, soil water storage and physical properties) fit the simpler monofractal model considered in this paper (such an effort would require paying close attention to the support and sampling window scales of the data). Parsimony would suggest associating variables found to fit both models equally well with the latter. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献