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51.
Very little work has been done in generating alternatives to the Poisson process model. The work reported here deals with
alternatives to the Poisson process model for the earthquakes and checks them using empirical data and the statistical hypothesis
testing apparatus. The strategy used here for generating hypotheses is to compound the Poisson process. The parameter of the
Poisson process is replaced by a random variable having prescribed density function. The density functions used are gamma,
chi and extended (gamma/chi). The original distribution is then averaged out with respect to these density functions. For
the compound Poisson processes the waiting time distributions for the future events are derived. As the parameters for the
various statistical models for earthquake occurrences are not known, the problem is basically of composite hypothesis testing.
One way of designing a test is to estimate these parameters and use them as true values. Momentmatching is used here to estimate
the parameters. The results of hypothesis testing using data from Hindukush and North East India are presented. 相似文献
52.
Mohammad Ashtari Jafari 《Natural Hazards》2007,42(1):237-252
The Bayesian probability estimation seems to have efficiencies that make it suitable for calculating different parameters
of seismicity. Generally this method is able to combine prior information on seismicity while at the same time including statistical
uncertainty associated with the estimation of the parameters used to quantify seismicity, in addition to the probabilistic
uncertainties associated with the inherent randomness of earthquake occurrence. In this article a time-independent Bayesian
approach, which yields the probability that a certain cut-off magnitude will be exceeded at certain time intervals is examined
for the region of Alborz, Iran, in order to consider the following consequences for the city of Tehran. This area is located
within the Alpine-Himalayan active mountain belt. Many active faults affect the Alborz, most of which are parallel to the
range and accommodate the present day oblique convergence across it. Tehran, the capital of Iran, with millions of inhabitants
is located near the foothills of the southern Central Alborz. This region has been affected several times by historical and
recent earthquakes that confirm the importance of seismic hazard assessment through it. As the first step in this study an
updated earthquake catalog is compiled for the Alborz. Then, by assuming a Poisson distribution for the number of earthquakes
which occur at a certain time interval, the probabilistic earthquake occurrence is computed by the Bayesian approach. The
highest probabilities are found for zone AA and the lowest probabilities for zones KD and CA, meanwhile the overall probability
is high. 相似文献
53.
Application of bivariate extreme value distribution to flood frequency analysis: a case study of Northwestern Mexico 总被引:1,自引:0,他引:1
Carlos Escalante-Sandoval 《Natural Hazards》2007,42(1):37-46
In Mexico, poverty has forced people to live almost on the water of rivers. This situation along with the occurrence of floods
is a serious problem for the local governments. In order to protect their lives and goods, it is very important to account
with a mathematical tool that may reduce the uncertainties in computing the design events for different return periods.
In this paper, the Logistic model for bivariate extreme value distribution with Weibull-2 and Mixed Weibull marginals is proposed
for the case of flood frequency analysis. A procedure to estimate their parameters based on the maximum likelihood method
is developed. A region in Northwestern Mexico with 16 gauging stations has been selected to apply the model and regional at-site
quantiles were estimated. A significant improvement occurs, measured through the use of a goodness-of-fit test, when parameters
are estimated using the bivariate distribution instead of its univariate counterpart. Results suggest that it is very important
to consider the Mixed Weibull distribution and its bivariate option when analyzing floods generated by a␣mixture of two populations. 相似文献
54.
55.
56.
通过对非洲、澳大利亚、南美洲彼此之间的大陆架边界线相似的概率分析,指出巧合是不可能的,地球在过去几十亿年间一定发生了大规模的膨胀。 相似文献
57.
本文提出了考虑各潜在震源相互耦合的等效物理模型,系统地建立了通过拟合各潜在震源地震序列来确定不同时间段内活断层形速率的方法,给出了预报各潜在震源未来一定年限内发生震级在不同震级段的概率模型。 相似文献
58.
以东经108°线为界,把中国大陆分为东、西两部,东部取震级M≥6的地震、西部取M≥7的地震为强地震.利用有史以来全部地震资料,针对不同情况和不同时期,系统地研究了相继两次强地震之间的时间间隔,目的在于讨论一次强地震发生之后,下一次强地震何时发生.在所有情况下地震间隔数目都随时间间隔值的增大呈明显的趋势性减小.给出了8种情况下的间隔数目统计和相应的模拟函数,以及间隔值的经验概率和相应的函数模拟概率.由此可估计时间间隔为某个值的概率,也可估计时间间隔处于某个区间的概率.反之,对于给定的概率,可估计时间间隔的值或它所处的区间. 相似文献
59.
Oliver Wild Oliver V. Rattigan Roderic L. Jones John A. Pyle R. Anthony Cox 《Journal of Atmospheric Chemistry》1996,25(2):167-199
The Cambridge 2-D Eulerian model has been used to study the potential atmospheric distributions and lifetimes of a number of CFC replacement compounds and their degradation products. The study has focused on HFC 134a and HCFCs 123, 141b and 142b and the major products formed by their atmospheric degradation. The loss of these compounds and their products by hydroxyl radical attack, photolysis and in-cloud hydrolysis have been investigated. The study has shown that HCFCs 141b and 142b have sufficiently long lifetimes to enter the stratosphere in significant quantities, where degradation leads to an increase in the total stratospheric chlorine concentration. The study has also highlighted areas where further experimental work would be valuable, in particular characterisation of the product channels for the degradation reactions and determination of the removal rates of the products in the aqueous phase. 相似文献
60.
Zipf's Law is a mathematical expression of the relationship between size and rank orders of some discrete phenomena. We have used this relationship to predict the undiscovered viable copper reserves for the Zambian Copperbelt. This prediction has been reinforced by canvassing geological opinion. As two semi-numerate exploration geologists, we naively risk predicting the undiscovered gold resources of the West Australian shield.This paper was presented at Symposium 116.3, Quantitative Strategy for Exploration, held as part of the 25th International Geological Congress, Sydney, Australia, August 1976. 相似文献