InSAR资料约束下震源参数的PSO混合算法反演策略

A novel hybrid PSO/simplex algorithm for determining earthquake source parameters using InSAR data

本文分析了InSAR资料用于震源参数反演中的参数特点,提炼了适合震源反演问题的POS技术路线.InSAR资料约束下的有限断层参数反演问题中,不同参数对目标函数的敏感度存在明显差异,而且断层的面积与滑动量间存在一定的折中关系.为此,使用局部PSO算法机制进行全局搜索,利用一维参数迭代过程中分布函数描述局部极小,并将自动识别出局部极值作为Simplex算法的初始模型作更高精度搜索.新的震源参数反演策略在均一滑动矩形断层参数反演中,较少参数约束下即可确保获得较高的成功率的效果.本文将该算法成功应用于三种不同类型的地震类型:(1)2003年伊朗Bam地震(走滑型),(2)1998年张北-尚义地震(倾滑型),和(3)模拟的正断层兼右旋走滑事件.所得结果均表明该策略的实用性和可靠性.

The paper presents a Paticles Swarm Optimization （PSO） and Simplex integrated approach to determine source parameters using InSAR data. In earthquake source parameter inversion, thereare differences in the sensitivity of different parameters to the objective function and a trade-of/between the fault area and slip. We proposed that： （1） a local PSO algorithm is employed to perform a global search, （2） a 1-D Probability Desity Function （PDF） is utilized to describe the local minimum in the full parameters space, which is automatically recognized as the initial model in the Simplex algorithm inversion. The PSO/Simplex integrated approach has been successfully applied to three different earthquakes： the 2003 Barn （Iran） earthquake （strike-slip）, the 1998 Zhangbei （China） earthquake （dip-slip）, and a simulated event with a normal fault with right-lateral slips. All the case studies sugguest the robustness and reliability of the integrated approach.