【摘要】 为克服InSAR观测汶川地震同震形变场的邻轨不连续问题,提出联合GPS观测值与邻轨平滑约束的同震位移校正方法,采用GPS观测形变去除PALSAR轨道误差引入的残留平地相位,基于形变平滑条件校正邻轨干涉相位的不连续性.ALOS/PALSAR干涉处理结果表明,校正后同震形变场的准确度与平滑性得以显著提高,InSAR高相干点残差达3.6cm,校正后精度提高约60%,低相干点精度提高约40%,校正后形变场的邻接平滑因子标准差减小约33%,验证了轨道误差校正与邻轨平滑约束方法的准确性与可靠性.进一步基于弹性半空间位错模型的断层滑移反演结果表明,断层滑移主要分布于映秀、北川和青川地区,集中于地壳深度0~16km范围,最大滑动量(位于北川县城)约为9.0m,GPS反演模型残差为5.5cm,InSAR反演模型残差达9.2cm,InSAR反演精度约有30%的显著提高,由模型反演计算得到的地震矩为8.0469×1020 N·m.更多还原

【Abstract】 In order to overcome the discontinuity of InSAR derived coseismic interferogram,a new method was proposed for the fringe correction with GPS observations and adjacent smoothening conditions.The GPS observations were employed to model the residual flat-earth phase and the interferometric fringes between adjacent orbits were smoothened with geometric constraints.The corrected coseismic deformation with ALOS/PALSAR images shows that theaccuracy and smoothness were significantly improved.The RMSE of InSAR high coherent area reaches 3.6cm with a 60% decrease,and that of low coherent area decreased by 40%.The smoothness factors are also improved by 33%.The correction results validated the feasibility and reliability of proposed method.The fault slip model was derived from the Okada dislocation model with InSAR and GPS deformation field.The results show that the main fault slip happened in 0~16km depth in the crust in Yingxiu,Beichuan and Qingchuan area.The maximum slip is about 9.0mlocated in Beichuan area.The inversion residuals of GPS and InSAR observations reach 5.5cm and 9.2cm respectively.The inversion accuracy of InSAR corrected deformation field was improved by 30%.The derived seismic moment from the refined fault slip model reaches 8.0469×1020 N·m.更多还原