【摘要】 通过研究近场强震动记录,发现汶川Ms8.0地震近场峰值加速度在空间上存在较明显的上盘效应和方向性效应,与汶川引起的地质灾害空间分布具有较好的一致性.但在所有强震仪所记录的汶川Ms8.0地震同震加速度记录积分所得地壳同震速度中,有的台站数据存在典型的线性偏移,有的台站数据除线性偏移外还存在明显的非线性偏移.采用非线性基线改正方法处理汶川Ms8.0强震同震记录,改正后所得同震位移明显要比线性基线改正更合乎实际情况.以强震动、GPS和InSAR同震位移处理结果做约束,反演了汶川Ms8.0地震同震位错分布,对于汶川Ms8.0地震主要同震破裂断裂(北川-映秀断裂),强震动反演结果不仅较好地刻画了汶川Ms8.0地震同震主断裂上地表破裂空间分布详细变化特征,同时也较好地反映北端破裂衰减情况,该结果表明:强震动资料可以为强震后的救援和灾害评估等工作提供具有参考价值的研究结果;另一方面,受数据数量的制约,用强震动改正后位移反演所得位错分布中仅汉旺断裂南段存在较为明显位错,强震仪布设时应更多地考虑是否相对均匀地分布在具有发震潜势的断裂周缘,以期更好地在震后应急救灾中发挥更好的作用.更多还原

【Abstract】 Based on the near-field strong-motion records,the distribution of peak acceleration near the Wenchuan Ms8.0earthquake exists obvious hanging wall and directivity effect,it is consistent with the distribution of geological hazard caused by Wenchuan earthquake.However,among the crustal co-seismic velocities which are achieved by integrating the acceleration of Wenchuan Ms8.0earthquake recorded by strong motion seismograph,there is a typical linear offset for some stations,and there are also obvious nonlinear offsets besides linear offset for some other stations.Using the approach of nonlinear baseline correction to process co-seismic records of Wenchuan Ms8.0earthquake,the co-seismic displacement corrected by the nonlinear approach obviously is in better agreement with actual situation than the linear baseline correction approach.As a constraint of displacement processing results of strong-motion,GPS and InSAR,this paper inverts the distribution of co-seismic dislocation of Wenchuan Ms8.0earthquake.For the main co-seismic rupture fault of Wenchuan Ms8.0earthquake(Beichuan-Yingxiu fault),the inversion result of strong-motion is not only nicely characterize the detailed variation of distribution of co-seismic surface rupture on the main fault,but also well reflect the rupture attenuation on northernmost fault.The results show that,strong-motion data could provide valuable results for post-seismic rescue and disaster assessment.In addition,due to data limitations,for the location distribution which inverted from displacement corrected by strong motion,only the southern section of Hanwang fault exists obvious dislocation.It reveals that we should emplace the strong motion seismographs relatively uniform around the potential seismogenic faults,in order to play a better role in the post-seismic emergency rescue.更多还原