基于MGR模型修正我国大陆中强以上地震的震级-频度关系和确定震级极限值

Modification of magnitude-frequency relation and magnitude limit determination based on MGR model for moderate-strong earthquakes in Chinese mainland

从理论上推导了修正的古登堡-里克特模型的震级上限的确定方法,应用常用的两种模型对我国分区域进行了震级-频度关系的修正和震级极限值的确定.结果表明,我国大陆存在非线性的震级-频度关系,传统的NGR模型不能反映非线性的震级-频度关系,而MGR模型能反映适合非线性和线性的震级-频度关系,因此MGR模型适合我国各研究区中强以上地震的震级-频度关系.当震级-频度关系为非线性时,用MGR模型确定的震级极限值较准确.

In this paper the method of determining upper magnitude limit following modified Gutenberg-Richter model is derived.Based on two commonly used models the modified magnitude-frequency relations and upper magnitude limits for various regions of Chinese mainland are determined.The result shows that there are nonlinear magnitude-frequency relations for earthquakes in Chinese mainland and the traditional normal G-R model can not reflect nonlinear feature of actual magnitude-frequency relations.While MGR model is suitable for expressing both linear and nonlinear magnitude-frequency relations,and is more suitable for dealing with moderate-strong earthquakes in various regions of Chinese mainland.When the magnitude-frequency relation is nonlinear,the upper magnitude limit determined by using MGR model is more reasonable.