In the second step, short wavelength velocity variations are included into the model by conjugate gradient method, and waveform information in intercept time-slowness domain is used.

• 第二步，利用波形资料用共轭梯度法求得速度的短波长扰动分量。这样，最后反演得到的速度结构模型包含了长波长与短波长分量。