强震前b值的变化特征

Variation characteristics of b value before strong earthquakes

b值的变化可以反映地震的活动性,是地震的预测预报研究的重要参数之一。利用最小二乘法和最大似然法对中国大陆强地震前b值的变化特征进行研究分析。结果表明,大震发生前,b值存在异常变化并有一定相似性,变化过程和应力积累过程吻合,与震源机制关系无明显联系;在研究b值随时间变化时,极大似然法相对受限小,能更好地反映强震前后b值的变化特征。

The change of b value can reflect the activity of earthquakes,and is one of the important parameters in earthquake prediction research.In this paper,the least square method and the maximum likelihood method are used to study the variation characteristics of b value before strong earthquakes in China's Mainland.The results show that before the occurrence of a strong earthquake,there is an abnormal change in b value,and the changes have a certain similarity.The change process is consistent with the stress accumulation process,while it has no obvious relationship with the focal mechanism.When studying the b value change with time,the maximum likelihood method has relatively small restriction,and can better reflect the change characteristics of b value before and after strong earthquakes.