Early Estimation of Strong Aftershock Duration Time     

Zhou Cuiying  Wang Hongwei  Wang Mei  and Zhang YuxiaSeismological Bureau of Shandong Province  Jinan  China Center for Analysis  Prediction  SSB  Beijing  China 《中国地震研究》1997,(4)

In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given.  相似文献   

Regionalization of unit hydrograph Parameters: 2. Uncertainty analysis     

K. -C. Yeh  J. -C. Yang  Y. -K. Tung 《Stochastic Environmental Research and Risk Assessment (SERRA)》1997,11(2):173-192

Hydrologic model parameters obtained from regional regression equations are subject to uncertainty. Consequently, hydrologic model outputs based on the stochastic parameters are random. This paper presents a systematic analysis of uncertainty associated with the two parameters, N and K, in Nash's IUH model from different regional regression equations. The uncertainty features associated with N and K are further incorporated to assess the uncertainty of the resulting IUH. Numerical results indicate that uncertainty of N and K from the regional regression equations are too significant to be ignored.  相似文献   

Regionalization of unit hydrograph Parameters: 2. Uncertainty analysis     

K. -C. Yeh  J. -C. Yang  Y. -K. Tung 《Stochastic Hydrology and Hydraulics》1997,11(2):173-192

Hydrologic model parameters obtained from regional regression equations are subject to uncertainty. Consequently, hydrologic model outputs based on the stochastic parameters are random. This paper presents a systematic analysis of uncertainty associated with the two parameters, N and K, in Nash's IUH model from different regional regression equations. The uncertainty features associated with N and K are further incorporated to assess the uncertainty of the resulting IUH. Numerical results indicate that uncertainty of N and K from the regional regression equations are too significant to be ignored.  相似文献   

建设用地地质灾害危险性评估中几个问题的思考   总被引：7，自引：3，他引：7  

金德山 《中国地质灾害与防治学报》2004,15(4):101-103

结合工作实践，就建设用地地质灾害危险性评估及其成果审查工作中经常遇到的5个问题——评估灾害类型的确定原则，评估区环境条件分析深度的把握，现状、预测及综合地质灾害危险性评估内容的侧重点，土地适宜性评价的依据以及优秀评估成果的判定标准，提出了个人的理解和认识。供从事类似工作的同志参考。  相似文献   

GOCE Gravity Field Processing Strategy     

Pail  R.  Plank  G. 《Studia Geophysica et Geodaetica》2004,48(2):289-309

A processing strategy and the corresponding software architecture for the processing of GOCE (Gravity field and steady-state Ocean Circulation Explorer) observables is presented and described, with the major objective to compute a high-accuracy, high-resolution spherical harmonic model of the Earth's gravity field. The combination of two numerical solution strategies, i.e. the rigorous solution of the corresponding large normal equation systems applying parallel processing (on a PC cluster) as the core solver, and the fast semianalytic approach as a quick-look gravity field analysis (QL-GFA) tool, is proposed. Such a method fusion benefits from the advantages of the individual components: the rigorous inversion of the system providing also the full variance-covariance information, and the quickness enabling the consecutive production of intermediate gravity field solutions, for the purpose to analyse partial and incomplete data sets and to derive a diagnosis of the performance of the GOCE measurement system. The functionality and operability of the individual components are demonstrated in the framework of a closed loop simulation, which is based on a realistic mission scenario both in terms of the orbit configuration and the coloured measuring noise. Special concern is given to the accuracy of the recovered coefficients, the numerical behaviour, the required computing time, and the particular role of the individual modules within the processing chain. In the case of the core solver, it is demonstrated that the assembling and rigorous solution of large normal equation systems can be handled by using Beowulf clusters within a reasonable computing time. The application of the quick-look tool to partial data sets with short-term data gaps is demonstrated on the basis of several case studies. Additionally, the spectral analysis of the residuals of the adjustment is presented as a valuable tool for the verification of the noise characteristics of the GOCE gradiometer.  相似文献   

On the Incorporation of the Effect of Crustal Structure into Empirical Strong Ground Motion Estimation     

J. Douglas  P. Suhadolc  G. Costa 《Bulletin of Earthquake Engineering》2004,2(1):75-99

This article has two purposes. Firstly, a validation exercise of the modal summation technique for the computation of synthetic strong-motion records is performed for two regions of Europe (Umbria-Marche and south Iceland), using a variety of region specific crustal structure models, by comparing the predicted ground motion amplitudes with observed motions. It is found that the rate of decay of ground motions is well predicted by the theoretical decay curves but that the absolute size of the ground motions is underpredicted by the synthetic time-histories. This is thought to be due to the presence of low-velocity surface layers that amplify the ground motions but are not included in the crustal structure models used to compute the synthetic time-histories. Secondly, a new distance metric based on the computed theoretical decay curves is introduced which should have the ability to model the complex decay of strong ground motions. The ability of this new distance metric to reduce the associated scatter in empirically derived equations for the estimation of strong ground motions is tested. It is found that it does not lead to a reduction in the scatter but this is thought to be due to the use of crustal structure models that are not accurate or detailed enough for the regions studied. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Research on the effect estimation of seismic safety evaluation     

邹其嘉  陶裕禄 《地震学报(英文版)》2004,17(1):87-98

IntroductionItisdefinitelystipulatedintheLawofthePeople'sRepublicofChinaonProtectingagainstandMitigatingEarthquakeDisastersthattheseismicsafetyevaluationmustbemadeformajorprojects(includinglifelineprojects)and,accordingtotheresultsobtained,theseismicresistancerequirementsshouldbedetermined.Thenecessityofseismicsafetyevaluationhasbeenrecog-nizedgradually,butthetopicontheeffectofsafetyevaluationhasnotbeenreferredmuch.Gener-allyspeaking,althoughmostpeopleapprovethesocialeffectofsafetyevaluatio…  相似文献   

A new method for testing pile by sin- gle-impact energy and P-S curve     

许昭永  段永康  王彬  胡毅力  杨润海  许峻  赵晋明 《地震学报(英文版)》2004,17(Z1)

Introduction Through many year's practices by vast numbers of scientific and technological workers andefforts from all aspects, the dynamic testing method of high-low strain has formally entered intothe technical code of foundation pile test of construction at last (The Industry Standards of thePeople's Republic of China, 2003). The striking mode of the dynamic testing method of high strainis stipulated as hammer in the code, the striking of rocket can also be used. The latter is widely…  相似文献   

应用GMS5多通道云图估计降水技术的研究     

杨引明  姚祖庆 《气象》2004,30(11):8-13

对近两年来5～8月中国东部地区120多个测站雨量观测资料和对应4400多幅GMS-5四个通道云图的研究发现：红外亮温的时间、空间变率、红外和水汽通道亮温差等云图衍生资料对消除卷云，弥补夜间缺少可见光云图的不足起到明显作用。从而，应用双判据双重MOS多元回归法建立四通道云图因子、衍生因子与降水量之间的回归方程，进行6小时分级降水估计。为了进一步消除厚卷云和特殊地形的影响，提出使用逐日实时资料自动建立多元回归方程估计降水量，从而对双判据双重MOS多元回归法估计结果进行校正。上海中心气象台的业务使用表明，总体估计的准确率达70％左右。  相似文献   

阿克苏霜期规律初探   总被引：2，自引：0，他引：2  

陈颖  史红政 《沙漠与绿洲气象(新疆气象)》2004,27(2):16-17

通过分析1971～2000年阿克苏市初、终霜期及无霜期序列，初步探讨了它们的变化趋势、分布频率等气候特征，指出了初霜期推迟、终霜期提前、无霜期增长的变化趋势，而这种变化趋势与气候变暖理论相一致。  相似文献