Stress-driven fluid flow controls long-term megathrust strength and deep accretionary dynamics
Stress-driven fluid flow controls long-term megathrust strength and deep accretionary dynamics
复制标题
应力驱动的流体流动控制长期的巨型逆冲强度和深层增生动力学
作者：
A. Menant;S. Angiboust;T. Gerya
大逆冲地震带摩擦强度的非均质性对板块耦合和长期俯冲动力学具有重要的控制作用。然而，高摩擦段在空间和时间上的持久性和分布仍然没有得到很好的限制。在这里，我们表明，增生过程，如构造底沉积（即弧前区域以下物质的基底增生），可以作为表征俯冲界面长期摩擦分带的代理。我们进行了数值热力学实验，预测了构造应力变化对弧前深部流体输运的一级控制。因此，流体分布和有效应力之间的正反馈有利于界面摩擦特性在myr尺度上的稳定性，从而控制深部吸积动力学。我们提出，识别由数十Myr连续的海底事件造成的厚复式构造，可以跟踪表现出日益增加的摩擦行为的俯冲段。数值结果有助于确定世界范围内确认活动构造底板的特大逆冲地震带的长期水力学性质和耦合/解耦段的分布。
The heterogeneity of frictional strength along the megathrust earthquake zone critically controls plate coupling and long-term subduction dynamics. However, the persistence and distribution of high-friction segments through space and time remain poorly constrained. Here, we show that accretion processes, such as tectonic underplating (i.e., basal accretion of material below the fore-arc region), can be used as a proxy to characterize the long-term frictional zonation of the subduction interface. We carry out numerical thermo-mechanical experiments, which predict a first-order control of tectonic-stress variations on fluid transport in deep fore-arc regions. Accordingly, positive feedback between fluid distribution and effective stress favours the stability of the interface frictional properties at Myr-scale which, in turn, controls the deep accretionary dynamics. We propose that the recognition of thick duplex structures resulting from successive underplating events over tens of Myr, allows for tracking subduction segments exhibiting an increasing frictional behaviour. Our numerical results help ascertain the long-term hydro-mechanical properties and distribution of coupling/decoupling segments of megathrust earthquake zones worldwide where active tectonic underplating is recognized.
影响因子：
18.3
作者：
Moreno, M.;Li, S.;Oncken, O.
通讯作者：
Oncken, O.
影响因子：
3.7
作者：
C. Ranero;I. Grevemeyer;H. Sahling;U. Barckhausen;C. Hensen;K. Wallmann;W. Weinrebe;P. Vannucchi;R. Huene;K. Mcintosh
通讯作者：
C. Ranero;I. Grevemeyer;H. Sahling;U. Barckhausen;C. Hensen;K. Wallmann;W. Weinrebe;P. Vannucchi;R. Huene;K. Mcintosh