2005年前东北地区地震趋势预测   总被引：2，自引：3，他引：2  

于龙伟  卢群 《东北地震研究》1993,(1)

从地震活动时间序列的自然节律和地震天文周期等方面,对2005年以前东北地区浅震和深震的趋势,作了分析和预测。经χ~2检验可知。东北浅震受18.6年周的月球升交点运动和22年周的太阳黑子磁场交变影响较显著。综合预测,第五活跃期的时段为:1995年—2005年,在南、中北区内,都将发生5级以上地震。在未来活跃期内,发生7级地震的可能性很小,但发生两次以上6级强震的可能性较大,且可能在中区和南区发生。东北深震没有明显的自然周期和天文周期。综合预测,6级以上深震未来活动时段为:1996年—2008年。  相似文献   

用卫星资料估计降水方法的评述   总被引：2，自引：3，他引：2  

王健康 《气象》1993,19(5):3-8

  相似文献   

水文水资源系统贝叶斯分析现状与前景   总被引：17，自引：2，他引：17       下载免费PDF全文

黄传军  丁晶 《水科学进展》1994,5(3):242-247

简介了贝叶斯分析的基本原理,综述了它在水文水资源系统中考虑不确定性和风险的特点及其在径流预报、洪水分析与地区综合、水资源规划与管理等问题中的应用,并分析了其发展前景,着重指出将灰色先验分布、模糊似然函数在贝叶斯定理框架中耦合的综合途径.  相似文献   

Estimation of Earthquake Hazard Parameters Based on the Unequal-Accuracy Catalog     

Sbao Huicheng  Chen Dangmin  Zhang ChunshengSeismological Bureau of Shaanxi Province  Xi'an  China 《中国地震研究》1994,(4)

In this paper,the maximum likelihood estimation of earthquake hazard parameters(β,Mmax)is extended to those data including incomplete and uncertain parts.We calculated earthquake hazard parameters of the Fenwei seismic belt,and the border area between Shaanxi,Sichuan,Hubei and Henan Provinces.The result is comparatively stable and gives an objective evaluation of earthquake hazard.  相似文献   

Estimation of the Mesozoic geological time scale     

Frederik P. Agterberg 《Mathematical Geology》1994,26(7):857-876

Geological time scales are constructed by combining the stratigraphic record with radiometric dates and their standard deviations. The stratigraphic record encompasses litho-, bio-, chrono-, and magnetostratigraphy. The statistical methods employed should embody concepts and data available for the systems considered. Recently, in order to estimate the ages of 31 Mesozoic stage boundaries, use was made of a database with chronostratigraphic classifications for 340 dates, biostratigraphic data including ammonite subzones, and information on seafloor spreading. This paper is primarily concerned with the propagation of errors through the successive steps of the data analysis. The following stepwise approach was taken for combining the different types of data: (1) maximum likelihood estimation with windows set around prior stage boundary estimates, (2) averaging of estimates with variable precision including magnetochronologic data, and (3) calibration by means of cubic smoothing splines assuming equal duration of ammonite subzones. The end product is a time-scale in which the stage boundary ages are accompanied by approximate 95 per cent confidence intervals.  相似文献   

地下水动态观测网优化设计研究   总被引：4，自引：0，他引：4  

仵彦卿 《地质灾害与环境保护》1994,5(3):56-64

本文采用状态空间分析法,通过对地下水流系统输入变量、输出变量及地下水动态测量值的研究,提出了地下水流系统确定一随机性数值模型。运用该模型的模拟解,进行地下水动态观测网优化设计。该方法把地下水动态观测网密度、位置及观测频率优化与地下水流系统结合起来研究。为了克服该模型计算量大的缺陷,本文提出了一种改进算法,使这一观测网优化方法适于在微机上实现,减少了计算工作量。该方法曾用于陕西某地区地下水位动态观测网的优化设计,取得了显著经济效益。  相似文献   

地理数据线性回归中的稳健估计方法     

吴健平  张立 《干旱区地理》1994,17(1):83-88

在线性回归中，常用最小二乘估计求线性方程的回归系数。但最小二乘估计受异常值影响较大，当样本数据存在异常值时，估计出的回归系数会产生较大偏差。稳健估计是最小二乘估计的改进，能在不排除异常数据的情况下，达到减弱异常数据对结果的影响。利用稳健估计提出黄土地区沟谷密度与侵蚀量的回归方程，并和最小二乘估计得到的回归方程比较，前者具有更回归效果。  相似文献   

地质统计学与分形理论的某些结合应用   总被引：6，自引：0，他引：6  

王仁铎 《地质科技情报》1993,12(3):93-97

概述了早期的结合应用有分维的计算、地质曲面模拟;近期的有空间估值、储层非均质性模拟、构造人工中间测线、分形谱及其参数等方面的结合应用。  相似文献   

Adaptive adjustment of channel geometry     

R. J. Bennett 《地球表面变化过程与地形》1976,1(2):131-150

This paper constructs a model of channel geometry composed of three subsections: a steady-state submodel, a gradedstate submodel, and a stochastic error submodel. With the aid of this representation of the morphology of channels, the at-a-point changes in geometry can be reproduced by a simple recursive equation of autoregressive, moving-average form which is derived from methods used in the statistical analysis of time series. A set of height loss data for three Japanese rivers derived from Yatsu's (1955) paper is used to determine the effect of bed material changes on adaptations within the graded-state submodel of the channel. The results of analyzing the autocorrelation function, spectrum, and adaptive parameter shifts within this model can be used to infer that significant changes in the amplitude of height change variation, and a shift to higher frequency oscillations of bed forms are associated with the shift in bed material conditions.  相似文献   

Seismic hazard estimate for a low seismicity region — Example of Bohemia     

Zdeňka Schenková  Vladimír Schenk  Vít Kárník 《Pure and Applied Geophysics》1981,119(5):1077-1092

The contribution reviews basic concepts of earthquake hazard assessment for sites of nuclear power plants. Taking into account the delineation of earthquake source regions, intensity-frequency relations, upper intensity thresholdsI _max and intensity attenuation curves, we determine the seismic hazard for a site in south Bohemia and calculated the quantities defining the seismic hazard, i.e. return period in years, probability of exceedance for different intensities and different periods of interest. The adopted procedure has some limitations due to the poor definition of seismogenic zones (boundaries,N(I),I _max) and lack of strong motion observations in Central Europe.Communication presented at the XVII General Assembly of the European Seismological Commission in Budapest, 21–29 August 1980.  相似文献