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131.
Modelling peak accelerations from earthquakes 总被引:1,自引:0,他引:1
This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
132.
《中国科学D辑(英文版)》2006,(Z2)
As well known, the methods of remote sensing and Bowen Ratio for retrieving surface flux are based on energy balance closure; however, in most cases, surface energy observed in experiment is lack of closure. There are two main causes for this: one is from the errors of the observation devices and the differences of their observational scale; the other lies in the effect of horizontal advection on the surface flux measurement. Therefore, it is very important to estimate the effects of horizontal advection quantitatively. Based on the local advection theory and the surface experiment, a model has been proposed for correcting the effect of horizontal advection on surface flux measurement, in which the relationship between the fetch of the measurement and pixel size for remote sensed data was considered. By means of numerical simulations, the sensitivities of the main parameters in the model and the scaling problems of horizontal advection were analyzed. At last, by using the observational data acquired in agricultural field with relatively homogeneous surface, the model was validated. 相似文献
133.
134.
水压致裂地应力测试方法在云南大理-丽江铁路隧道工程中的应用 总被引:6,自引:1,他引:6
利用水压致裂地应力测试方法对实际工程区进行了地应力测量,确定了工程区隧道围岩现今的地壳应力状态,即原地应力的大小和方向.根据地应力分布特征,分析了隧道开挖过程中发生岩爆等地质灾害的可能性.地应力测量数据的分析结果可作为隧道衬砌的设计、断面的选择及轴线方位的确定的科学依据. 相似文献
135.
对水平定向钻进(HDD)用钻杆的工作状况及主要失效形式进行了分析,对整体锻造钻杆和摩擦焊焊接钻杆进行了比较,对提高HDD钻杆质量的方法进行了探讨,并对使用中应注意的问题提出了一些建议。 相似文献
136.
圆柱状构件广泛存在于古建筑仿真中,为了提高古建筑深度图像圆柱拟合的精度,针对古建筑仿真3维建模的特点,提出基于高斯图获取圆柱拟合参数初始值,然后利用圆柱距离函数参数化法进行非线性最小二乘拟合的圆柱拟合方法。实验证明,该方法不仅具有较高的精度,而且拟合结果稳定可靠。 相似文献
137.
Kai-Wu Li 《地震学报(英文版)》1998,11(5):637-644
Studies by many scientists show that Hebei, China is an area with strong correlation between the tidal force and the occurrences
of major earthquakes, the Xingtai earthquake of 1966, the Hejian earthquake of 1967 and the Tangshan earthquake of 1976 were
triggered by the tidal force, in this paper the study on the common characteristics of their occurrence times confirms these
facts. The computed times of maximum horizontal of the semi diurnal solid tide tidal force show that the occurrence times
of the above mentioned earthquakes were close to the times of maximum horizontal tidal force of the semi diurnal solid tide
at new moon or full moon. The Longyao earthquake of M=6.8, the Ningjin earthquake of M=7.2 and the Hejian earthquake of M=6.3 occurred tens of minutes after the maximum horizontal tidal force of the semi diurnal solid tides, and the Tangshan earthquake
of M=7.8 occurred 16 minutes before the maximum horizontal tidal force. The tidal forces were directed to the west. This is their
temporal characteristic. It is generally accepted that the 1969 Bohai earthquake of M=7.4 and the 1975 Haicheng earthquake were not triggered by the tidal force. These events did not show such characteristics.
The temporal characteristics of the earthquakes indicate that the occurrences of these events were not random, but were controlled
by the tidal force from the sun and the moon, and triggered by the tidal force. These facts agree with the triggering mechanism
of the tidal force, are evidences of earthquakes triggered by tidal force. 相似文献
138.
华北地区GPS监测网建设,地壳水平运动与应力场及地震活动性的关系 总被引:17,自引:1,他引:16
简要地介绍了华北地区、特别是首都圈GPS地震监测网的布设、观测、数据处理方法案和监测精度等,较详细地分析了地壳水平形变与构造运动、应力场变化以及地震活动的性的关系。 相似文献
139.
Preliminary results of measuring the crustal deformation in Qinghai-Xizang area using GPS technique 总被引:5,自引:0,他引:5
GPS repetition measurement tbta in Qinghai-Xizatlg (Tibetan) area in 1992 and 1994 have been used to determine the change
rates of seven bascline vectors of Lhasa-Wenquan, etc. It is the first time to obtain the direct observation results of the
large-scale crustal horizontal motions in this area. Thesc preliminary results also for the first time provide the direct
observation evidence for some important geophysical and geological viewpoints, such as the northward gradual reduce of the
effect of the northward push-pressing to Eurasian continent by Indian Plate in the Qinghai-Xizang area, having a southward
strike slip movement of the Chuan-Dian diamond block, etc. 相似文献
140.