Low friction along the high slip patch of the 2011 Mw 9.0 Tohoku-Oki earthquake required from the wedge structure and extensional splay faults
Low friction along the high slip patch of the 2011 Mw 9.0 Tohoku-Oki earthquake required from the wedge structure and extensional splay faults
复制标题
DOI：
10.1002/grl.50682
复制
发表时间：
2013-08-28
影响因子：
5.2
通讯作者：
Pons, A.
中科院分区：
文献类型：
--
作者：
Cubas, N.;Avouac, J. P.;Pons, A.
我们分析了2011年东北冲地震期间大规模浅层滑动和前弧内向陆正断层激活所需的力学性质。我们发现，形态和内部结构的前弧密切遵循预测的临界库仑楔在水平压缩，这意味着一个高的内部孔隙压力比（λ =0.7+0.14/-0.48）和低的有效基底摩擦（mu（ef）（B）（f）=0.14+0.18/-0.04）。然后，我们表明，激活的正断层需要一个较低的有效基底摩擦下的外楔比下的内楔（亩（外）0.015），可能是由于瞬态动力学弱化与地震破裂。弧前正断层可以被认为是非常有效的动态削弱沿着的大逆冲断层的证据，并具有高海啸的潜在代表。
We analyze the mechanical properties needed to account for the large shallow slip during the 2011 Tohoku-Oki earthquake and the activation of landward normal faulting within the forearc. We show that the morphology and internal structure of the forearc follows closely the prediction of the critical Coulomb wedge in horizontal compression, implying a high internal pore pressure ratio (lambda=0.7+0.14/-0.48) and a low effective basal friction (mu(ef)(b) (f)=0.14+0.18/-0.04). We then show that the activation of the normal fault requires a lower effective basal friction beneath the outer wedge than beneath the inner wedge (mu(outer)0.015), possibly due to transient dynamic weakening associated to the seismic rupture. Forearc normal faults could be considered as evidence for very efficient dynamic weakening along the megathrust and typify megathrust with high tsunamigenic potential.