【摘要】 基于首都圈地震台网2002—2005年的区域地震波形数据,采用剪切波分裂系统分析方法(SAM),计算得到首都圈东南部地区(38.5°N—39.85°N,115.5°E—118.5°E)24个台站的剪切波分裂参数.结果表明,首都圈东南部地区快剪切波平均偏振方向与区域最大主压应力方向相近,与华北地区GPS主压应变测量结果一致;但首都圈东南部盆地地区的剪切波分裂观测结果与首都圈西北部的隆起—盆地构造结合区的观测结果不同.这说明了不同的构造对观测结果具有一定的影响.研究还表明,台站附近的断层分布状态对观测结果影响很大,复杂的断层分布会加剧剪切波分裂测量结果的离散程度.本研究区域南部台站与北部台站的快剪切波偏振方向存在较大差异,这可能与该区南北部的构造及应力环境存在较大差异有关.更多还原

【Abstract】 Shear-wave splitting parameters of 24 stations in southeastern Capital area (38.5°N--39.85°N, 115.5°E--118.5°E) are obtained with SAM(systematic analysis method of shear-wave splitting) based on the data from 2002 to 2005 of Capital Area Seismic Network (CASN). The results show that the average polarization of fast shear-wave in southeastern Capital area is consistent with regional maximum horizontal principal compressive stress in the area, and is also consistent with maximum horizontal principal compressive strain from GPS in Northern China. The average shear-wave splitting in southeastern Capital area (in basin) is different from that in northwestern Capital area where uplifts and basin exist, illustrating that different tectonics can show different shear-wave splitting results. Research also shows that the distribution of faults around stations can obviously affect the shear-wave splitting results, and complicated distribution of faults can result in much more scattering of shear-wave splitting. It is also shown that in the north and south of the interested area (southeastern Capital area), the polarizations of fast shear-wave are not very consistent, which may be related to differences in tectonic and stress for the two areas.更多还原