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911.
1 Introduction Earthquake disaster investigations show that numerous strong earthquakes were caused by remobilization of active faults. Major casualties and severe damage to buildings as well as signi?cant economic losses resulted from the ground motions of strongearthquakescausedbyactivefaultslocatedbeneath urban areas. Recently, the potential hazard prediction of and its mitigation against active faults located beneath urban areas have become an important research topic for seismologists and… 相似文献
912.
在研究多个工程场地钻孔资料的基础上,选取和构造了若干典型场地剖面,利用目前工程上广泛应用的场地地震反应分析的一维等效线性化波动方法,计算了各剖面在不同基底地震动输入的反应谱值及地表加速度峰值,分析了覆盖层厚度对反应谱峰值及峰值周期、地表加速度峰值和放大倍数的影响,得出了一些有意义的结论。 相似文献
913.
长周期地震动三维有限元数值模拟方法 总被引:1,自引:0,他引:1
采用数值方法对长周期地震动进行模拟已成为当前强地面运动预测的研究方向之一。本文提出了一种有限元并行计算的高效地震动数值模拟方法,可以同时考虑震源、传播途径和场地条件对地震动的影响,并根据昆明地区未来可能发生的设定地震对昆明市的影响地震动进行了预测。这一方法可以应用于国内已探测的发震活断层进行地震危害性评价工作。 相似文献
914.
Periodic changes in Universal Time and polar motion have been derived from a numerical ocean model for a number of small partial tides. Combined with the results reported earlier our model now includes the 34 most important constituents of degree 2 (measured by the amplitude of the tidal potential). The results show that the terms neglected in all existing models amount to 80 μs in UT1 and to 0.3 mas in polar motion. 相似文献
915.
916.
ZHANG Jianqing ZHANG Chunsen HE Shaojun 《地球空间信息科学学报》2006,9(1):32-37
Introduction Amongexistingvisionmoniteringandtheesti mationof3Dmotion,nearlyallinvestigations aremoniteringandtracingthemotionobject basedonsinglesequenceimages.Themotionin formationbyanalyzingthesinglesequenceima gesisrelative,whichincludesascaleoffactor… 相似文献
917.
DIFFERENCES BETWEEN DRY AND WET SUMMER IN THE VERTICAL MOTION ON NORTH SIDE OF QINGHAI-XIZANG PLATEAU AND THE THERMAL IMPACT OF PLATEAU*
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To better analyse and understand the causes of Northwest China(NW China) arid climate formation,firstly the dry and wet standards were chosen and the yearly dry and wet grades on the north side of Qinghai-Xizang Plateau(hereafter NSQXP) in summers were classified utilizing the rainfall data of five stations over the area in June-August of 1952-1990.Then the differences between the vertical motion over the Qinghai-Xizang Plateau(QXP) and NSQXP in dry and wet summers were comparatively analyzed using the ECMWF's gridded data of June-August of 1979-1986.Finally the connection between the QXP surface thermal condition and the dry and wet summers on the NSQXP was discussed as well.The main results are the following:(1)the dry and wet standards taking the rainfall standard deviation as criterion are suitable for the arid climate area;(2)the QXP may be,to some extent responsible for the environment background of Middle Asia,NW China and North China arid climate areas;(3)there are the striking differences between the dominant vertical motion over the QXP and NSQXP in the dry and wet summers of NSQXP:(4)the QXP surface thermal condition is to a great extent,responsible for the year-to-year variation of NW China arid climate as well. 相似文献
918.
南京河西地区设计地震动研究 总被引:7,自引:3,他引:4
本文根据南京及周围地区的地震环境,采用概率法对南京河西地区某高层公寓工程场址进行了地震危险性分析,采用等效线性化模型考虑场地土的非线性特性的影响,并用一维波动模型进行了场址土层地震反应和场地地震动效应分析,给出了50年超越概率63%,10%和3%的场址基岩和地表的水平向加速度反应谱值加速度。 相似文献
919.
IINTRODUCTIONItisveryoftentoobservegravelpericlesinformofimbricateclustersonmountainousriverbeds.Theparticleassemblagesareonaveragethreetosixparticlesinlengthandformassingle,highlyimbricatedlongitUdinalthreads.Theyneednotconsistofthelargestmaterialonthebed,eventhoughthisispredominantlythecase(DeJongandErgenzinger,1995).Theyaredifferentiatedintermsofshape,numberandarrangementofparticles,butmostlythelengthandthewidthoftheparticlesareafewtimesofthethickness.Willettsetal.(1982)investigatedt… 相似文献
920.
Osamu Kinoshita 《Island Arc》1999,8(2):181-189
A migration model of magmatism based on the granite ages in Southwest Japan is proposed to explain the ridge subduction beneath the Eurasia continent as the cause of the along-arc and across-arc youngings of the granite ages and the very high activity of the magmatism in the Cretaceous. For the construction of the magmatic model, the localities of the granite age samples are denoted by the cartesian coordinates X and Y, which are measured along and normal to the Median Tectonic Line (MTL), respectively, and their ages are set corresponding to the coordinate Z vertical to the X–Y plane. The age trend is then formulated by a regression plane of Z on X and Y, which inclines in both directions along and normal to the MTL, and approximates the ages with the very high multiple correlation coefficient 0.91. Evaluating the magmatic trend by such a method, various characteristics of the activities can be taken easily; for example, the isochronous line of the magmatism, which is an intersection of the regression plane and an arbitrary horizontal plane, is found to extend landward obliquely across the continental margin. The migrating rate of the isochronous line along the MTL is also taken to be 2.8 cm/year as a reciprocal of the inclination of the along-arc younging. The isochronous line is speculated to be the out-cropped manifestation of the subcrustal linear heat source. Such a migrating linear heat source is probably due to the subduction of an active ridge, the Kula (or Izanagi)–Pacific ridge in the Cretaceous. The migration model of magmatism harmonizes very well with the plates and the ridge motions in the East Asia area during the late Mesozoic. The ridge subduction is one of the important phenomena that explain the unusually active arc magmatism and the migrating slab window; it is important to grasp dynamically the geological messages issued from the system. 相似文献