地震的震级

简要介绍了地方性震级Mi、体波震级mb、面波震级Ms和矩震级Mw的定义及其测定方法，分析了它们的优点和缺点，并对震级饱和效应及其产生的原因作了介绍和解释。文章指出，矩震级是一个表征地震绝对大小的量，它与地震震源的物理过程直接关联，不会饱和；与传统上使用的其他震级标度相比，矩震级具有明显的优点，是当今国际地震学界推荐优先使用的震级标度。

Earthquake magnitude

In this paper,the definitions and the measurement methods of local magnitude M L ,body wave magnitude m b ,surface wave magnitude M S and moment magnitude M W are introduced and the advantagesas well as the disadvantages of these magnitude scales are analyzed.The effect of magnitude saturation is presented and explained.As an absolute measure of earthquake size,moment magnitude is directly related to physical process earthquake source and does not suffer from saturation.It is pointed out that the moment magnitude is superior to other traditional magnitude scales and is presently adopted as a prior magnitude scale to all others.