A window into the complexity of the dynamic rupture of the 2011 Mw 9 Tohoku-Oki earthquake
A window into the complexity of the dynamic rupture of the 2011 Mw 9 Tohoku-Oki earthquake
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DOI：
10.1029/2011gl048118
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发表时间：
2011-08-24
影响因子：
5.2
通讯作者：
Ampuero, Jean-Paul
中科院分区：
文献类型：
--
作者：
Meng, Lingsen;Inbal, Asaf;Ampuero, Jean-Paul
2011 年 Mw 9 东北冲地震由 1000 多个近场台站和多个大孔径阵列记录，是迄今为止地震学史上记录最好的地震，为解决震源动力学的基本问题提供了独特的机会。在这里，我们根据 USarray 和欧洲网络的记录进行高分辨率阵列分析。两个阵列相互一致的结果揭示了具有前所未有的分辨率的破裂复杂性，涉及不同破裂速度的阶段和慢速阶段内的间歇性高频爆发，这表明空间异质材料特性。地震最初向下倾传播，有一个缓慢的起始阶段，随后以 3 公里/秒的速度持续传播。然后破裂速度减慢至 1.5 km/s，持续 60 秒。沿着这个缓慢且大致圆形的破裂前沿的下倾边缘，产生了丰富的爆发序列。在慢速阶段结束之前，极快的破裂前沿以约 5 公里/秒的速度向北分离。最后，破裂前沿以约 2.5 公里/秒的速度向南传播，持续 100 多公里。 K-net 和 KIK-net 记录的强运动数据证实了破裂过程的关键特征。缓慢破裂阶段内的高能高频辐射事件表明脆性-延性过渡区的斑驳图像，由延性基体内离散的脆性粗糙体组成。高频主要产生于受大地测量学约束的主滑移区的下倾边缘，这表明巨型逆冲断层的力学特性沿倾角发生变化，或其空间异质性影响上升时间。引用：Meng, L.、A. Inbal 和 J.-P。 Ampuero (2011)，了解 2011 年 Mw 9 Tohoku-Oki 地震动态破裂复杂性的窗口，地球物理学。资源。快报，38，L00G07，doi：10.1029/2011GL048118。
The 2011 Mw 9 Tohoku-Oki earthquake, recorded by over 1000 near-field stations and multiple large-aperture arrays, is by far the best recorded earthquake in the history of seismology and provides unique opportunities to address fundamental issues in earthquake source dynamics. Here we conduct a high resolution array analysis based on recordings from the USarray and the European network. The mutually consistent results from both arrays reveal rupture complexity with unprecedented resolution, involving phases of diverse rupture speed and intermittent high frequency bursts within slow speed phases, which suggests spatially heterogeneous material properties. The earthquake initially propagates down-dip, with a slow initiation phase followed by sustained propagation at speeds of 3 km/s. The rupture then slows down to 1.5 km/s for 60 seconds. A rich sequence of bursts is generated along the down-dip rim of this slow and roughly circular rupture front. Before the end of the slow phase an extremely fast rupture front detaches at about 5 km/s towards the North. Finally a rupture front propagates towards the south running at about 2.5 km/s for over 100 km. Key features of the rupture process are confirmed by the strong motion data recorded by K-net and KIK-net. The energetic high frequency radiation episodes within a slow rupture phase suggests a patchy image of the brittle-ductile transition zone, composed of discrete brittle asperities within a ductile matrix. The high frequency is generated mainly at the down-dip edge of the principal slip regions constrained by geodesy, suggesting a variation along dip of the mechanical properties of the mega thrust fault or their spatial heterogeneity that affects rise time. Citation: Meng, L., A. Inbal, and J.-P. Ampuero (2011), A window into the complexity of the dynamic rupture of the 2011 Mw 9 Tohoku-Oki earthquake, Geophys. Res. Lett., 38, L00G07, doi:10.1029/2011GL048118.