【摘要】 2008年5月12日,四川省汶川县发生M_S8.0地震.我们利用美国阿拉斯加区域台网的邵分宽频带地震台构成广义台阵,应用非平面波台阵技术——迁移叠加方法,获得了这次地震的高频(>0.1 Hz)能量辐射源随时间和空间变化的图像.图像表明,这次地震破裂从震中开始向北东方向扩展约300 km,震源过程至少长达90 s,平均破裂速度为3.4 km/s;整个过程可分为两大阶段,前段持续时间50s,破裂长度约110 km,破裂传播的平均速度为2.2km/s,后段持续时间约40 s,长度约190 km,平均破裂速度为4.8 km/s.这意味着地震过程的后期似乎发生了超S波破裂,而且后段很可能为前段动态触发所致.更多还原

【Abstract】 On 12th of May, 2008, an M_S8. 0 earthquake occurred in Wenchuan county, Sichuan province of China. We configured a generalized array with the broadband seismic stations of the Alaska Regional Network,USA, and imaged the temporal and spatial variation of high-frequency (>0. 1 Hz) energy radiation sources by means of one of the non-plane wave array techniquesmigration stacking technique. The image shows that the earthquake faulting initiated at the instrumental epicenter and extended north-eastwards about 300 km, the whole rupture process lasted for at least 90s, and the average rupture speed was about 3. 4 km/s. The whole process may be divided into two major periods. The first period is 50 s and in this period the rupture propagated about 110 km, with an average rupture speed of 2. 2 km/s; the other period is 40 s and in this period the rupture propagated about 190 km, with an average speed of 4. 8 km/s. It seems that supershear rupture appeared in the later process of the earthquake, and the second segment might be dynamically trigged by the first one.更多还原