显然不是指数分布(永远年轻的现象).
Let x be the energy released and f(x) be the density fucntion. It should follow these propertyies,
(1) Integral from 0 to infinity is 1: S(f(x)dx=1
(2) f(x)>0
(3) f(x)=0 if x<=0
(4) (f(2x)/f(x)=1/4
Exponetian distribution f(x)=1/lamdaexp(-x/lamda)
does not mee these propertyies because
(f(2x)/f(x) is not a constant.
"震级发生的频率不是正态分布,但也不是毫无规律,而是震级越
高,则发生的频率越低。而且,它遵循一条简单的原则——幂律:一次地
震释放的能量每增加一倍,发生的频率就减少为四分之一"。