由于岗布尔(Gunbel)第三极值分布模型的独特优点(例如其震级上限∞等),地震专家把该模型应用到地震危险性研究。然而由于其复杂的非线性分布,以及地震数据的局限,极大地限制了在地震研究中的应用。为此,论述了以下两个方面的研究:挖掘拓宽和有效利用观测数据;确定初始参数以确保非线性拟合模型的收敛。该方法还能应用于弱震区地震发生规律的研究,为了阐述该方法的独特优点,对不同地震构造背景下的两组——中国东南的弱震区及希腊西部强震区地震数据进行了分析。研究证明对以上两个地震区的结果稳定且拟合误差小。
he Gumbel extreme model, especially the third distribution G(M) = exp[ - ( (ω-m)/(ω-μ)^1/λ] is used usually to earthquake risk research because of its prominent advantages, such as the upper bound to magnitude ω etc. Due to the complications of nonlinearity and the limitation of sparse observations, however, its importance has been largely underestimated. The methodology developed here concentrates on two aspects: exploring widening and adaptable use of the observations and finding the proper starting parameters to guarantee the convergence in the nonlinear fitting. Moreover, this new method makes it pos- sible to study the occurrence pattern of large earthquakes in low seismicity regions. In order to expound the distinctive advantage of this method, two data sets from different seismotectonic backgrounds, a low seismicity region from southeastern China and a high seismicity region from western Greece, are analysed. Both of these results are good and stable, as with low fitting errors.