汶川强余震流动观测与典型余震记录分析

The mobile strong-motion observation and preliminary analysis of typical records for Wenchuan aftershocks

2008年5月12日汶川大地震发生后,我国大陆的固定强震动台网获得了大批的主震加速度记录,中国地震局同时迅速组织开展了余震强震动流动观测任务。通过结合汶川地震余震趋势及其空间分布特征,此次流动观测沿龙门山断裂附近布设了59台强震动仪器,观测期间发生了超过万余次的余震,并获得了3000多组3分量的强余震记录。本文选取了4次震级为6.0左右的较强余震中获取的强震动记录进行简要谱分析及衰减关系对比,旨在为进一步结合主震记录,研究近场地震动特性、地震动衰减规律等地震工程相关的科研工作提供宝贵的基础资料。最后本文针对此次流动观测部分记录出现的异常现象进行初步探讨,给出了两种解释原因。汶川地震的流动观测充分表明,在大地震发生后,及时有效地开展强震动流动观测是十分必要的。

During the Wenchuan earthquake on May 12, 2008, National Strong Motion Observation Network System （NSMONS） of China captured hundreds of strong-motion records, and in the period more than 10 thousands of aftershocks occurred. In this paper, the mobile strong-motion observation for the disastrous earthquake is intro- duced. Following the aftershock characteristics and the spatial distribution, 59 strong-motion instruments were installed along the Longmenshan Fault, and more than 3000 groups of 3-chs record have been accumulated. The strong - motion data for 4 aftershocks were collected and preliminary analysis was done, which will benefit the further research, such as the near-field strong-motion characteristic and attenuation relationship. Finally, the causes of abnormal waveform with respect to a few of records are explored preliminarily, and two possible explanations have been presented. This observation task shows that it is necessary to perform the mobile strong-motion observation after the destructive earthquake and the collected precious data could be applied to further research.