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2010年2月27日智利MW8.8地震的多频率反投影结果揭示出此次地震是由具有不同滑动特征的子事件组成的。震中以南的子事件以低频(0.05～0.1Hz)释放能量,意味着滑动缓慢,且破裂速度约为0.8km/s。震中以北的2个子事件则显示出以高频(1～5Hz)释放能量的特征。其中第一个子事件似乎触发了北边第2段的滑动,并且释放了较高振幅的能量,传播速度也快,约为2.9km/s。除了这些破裂的细节之外,还观测到如下现象:在破裂前沿,高频能量释放之后紧接着产生了低频能量释放。这一发现表明:大震对应的破裂过程蕴含着断层的动态弱化,因此,它们的破裂特性并非简单地与小地震的特性相关。这些明显的滑动特点表明:有必要对宽频域各种数据进行研究,以便全面评估巨大地震的破裂过程及相关灾害。
The multi-frequency backprojection of the Chilean Mw8.8 earthquake on February 27, 2010 revealed that the earthquake consisted of sub-events with different slip characteristics. The sub-event south of the epicenter releases energy at low frequencies (0.05-0.1 Hz), meaning sluggish sliding with a rupture rate of about 0.8 km / s. The two sub-events to the north of the epicenter show features that release energy at high frequencies (1-5 Hz). One of the first sub-events appeared to trigger the sliding of the second-stage north and the release of higher-amplitude energy at a faster spread of about 2.9 km / s. In addition to the details of these ruptures, the following phenomena were also observed: at the rupture front, the release of low-frequency energy ensues immediately after the release of high-frequency energy. This finding shows that the fracture process corresponding to large earthquakes contains the dynamic weakening of faults, and therefore their rupture characteristics are not simply related to the characteristics of small earthquakes. These clear sliding features indicate that it is necessary to study various data in the wide frequency domain in order to fully evaluate the rupture process and related disasters of a huge earthquake.