接收函数反演上地幔速度结构和间断面的剥壳遗传算法

PEELING GENETIC ALGORITHM OF RECEIVER FUNCTIONS INVERSION FOR UPPER MANTLE STRUCTURE AND DISCONTINUITIES

探讨了使用台站接收函数反演得到上地幔速度结构和间断面深度的一种方法———剥壳遗传算法 .由地表至深部分成几个深度段 ,逐段反演速度结构 ,并在接收函数曲线上剥离浅处间断面的多次反射震相和反射转换震相对深部间断面的一次透射转换相的影响 .在每一深度段使用浮点编码、算术杂交和非均匀变异的遗传反演方法 ;在 10次独立反演后 ,依据适应度选出 5 0个优秀模型 ,对其加权平均得到该段的最终速度结构 .所形成的方法和程序 ,用iasp’91模型进行数值检验之后 ,又反演了海拉尔台的观测接收函数 ,给出台下深至 70 0km的速度结构和主要间断面埋藏深度及速度跃变量 .

To study the depths of seismic discontinuities in the upper mantle using the observed receiver function, this paper developed an inversion method of peeling genetic algorithm. The whole studied depth is divided into several sections from surface, and then inversion is made for each section. The effects of multiple reflected and reflect-transformed phases at the shallower discontinuities on the refract-transformed phase at the deeper one are peeled. Floating point coding, arithmetical crossover, and non-uniform mutation were used in the genetic algorithm in the inversion of each section. The method was checked using the model ispai'91 and applied to the inversion of velocity structure beneath HIA station.