Inversion of ocean-bottom seismometer （OBS） waveforms for oceanic crust structure： a synthetic study

作者：Xueyan Li,Yanbin Wang,Yongshun John Chen

摘要：The waveform inversion method is applied—using synthetic ocean-bottom seismometer(OBS) data—to study oceanic crust structure. A niching genetic algorithm(NGA) is used to implement the inversion for the thickness and P-wave velocity of each layer, and to update the model by minimizing the objective function, which consists of the misfit and cross-correlation of observed and synthetic waveforms. The influence of specific NGA method parameters is discussed, and suitable values are presented.The NGA method works well for various observation systems, such as those with irregular and sparse distribution of receivers as well as single receiver systems. A strategy is proposed to accelerate the convergence rate by a factor of five with no increase in computational complexity; this is achieved using a first inversion with several generations to impose a restriction on the preset range of each parameter and then conducting a second inversion with the new range. Despite the successes of this method,its usage is limited. A shallow water layer is not favored because the direct wave in water will suppress the useful reflection signals from the crust. A more precise calculation of the air-gun source signal should be considered in order to better simulate waveforms generated in realistic situations; further studies are required to investigate this issue.

发文机构：Department of Geophysics

关键词：海底地震仪地壳结构反演方法OBS波形海洋小生境遗传算法计算复杂度Waveform inversionOBSOceanic crustalstructureNiching genetic algorithm

分类号： P736.1[天文地球—海洋地质][天文地球—海洋科学]P315.2[天文地球—地震学][天文地球—固体地球物理学][天文地球—地球物理学]