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遗传算法是近年来发展较快的一种求解非线性优化问题的有效方法。本文通过对遗传算法基本原理的介绍，对该方法的特点进行了分析。我们采用ＷＫＢＪ理论地震图作正演，遗传算法作反演，对用体波波形反演上地幔速度结构的方法进行了研究。在ＷＫＢＪ理论地震图的计算中，通过计算主要射线的平均吸收特征时间，考虑了衰减随距离的变化，通过对不同震源引入不同的虚拟界面，同时对多个地震的波形记录进行反演。探讨了观测误差对反演结果的影响。对理论记录的反演表明，用遗传算法研究上地幔速度结构具有较好的效果。
Genetic algorithm is an efficient method to solve nonlinear optimization problems, which develops rapidly in recent years. In this paper, we introduce the basic principle of genetic algorithm, and analyze the characteristics of this method. We use the WKBJ theoretical seismogram as forward modeling and genetic algorithm as the inversion method to study the method of inverting the velocity structure of the upper mantle using the body waveform. In the calculation of WKBJ theoretical seismograms, by taking into account the average absorption characteristic time of the main ray, the change of attenuation with distance is considered, different virtual interfaces are introduced into different seismic sources, and waveform records of multiple seismograms are inverted at the same time. The effect of observation error on the inversion results is discussed. The inversion of the theoretical records shows that using genetic algorithm to study the velocity structure of the upper mantle has a good effect.