利用地震记录基线偏移估算同震地倾斜——以汶川地震为例

摘要

We illustrate the impact of ground tilt on baseline offset in an accelerogram and propose a method of estimation of co-seismic tilt based on acceleration record in the near-field of an earthquake. The method is applied to the records from 33 carefully selected stations in the 2008 Wenchuan earthquake, and the validity of the method is preliminarily confirmed. Our results show that large tilts in magnitude are obtained in near-fault or rupture-toward stations. No obvious characteristic is found in distribution of the tilt direction. The validity of the method needs further confirmation.%通过分析地倾斜对加速度记录基线偏移的影响,提出由近场强震加速度记录求取同震地倾斜的方法.应用汶川地震数据,初步确认了方法的正确性,得到汶川地震近场33个台站的同震地倾斜.结果表明,同震倾斜量较大的台站集中于断层周围以及破裂前方区域.倾斜方向上并未发现明显的空间规律性.该方法的有效性需要进一步研究.